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RadRes Fluoro

RadRes Preparation for Fluoro/Radiography Supervisor/Op Exam for Residents

QuestionAnswer
Long term effects of radiation exposure (such as cancer, etc.) are called: ...genetic effects? ...somatic effects? ...acute effects? ...teratogenic effects? somatic effects
One (1) electrostatic unit (esu) of charge due to the ionization of 0.001293 gram of air by radiation would be equal to 1 Roentgen. In Appendix 1. This is the old definition of charges liberated in air; SI definition is 2.58 x 10-4 C/kg air.
What is the maximum allowable exposure rate of a fluoroscopic beam which is used on a typical patient during routine fluoroscopy? The "typical" patient maximum allowable exposure rate is 5 R/min, although 10 R/min is allowable for larger than "typical" sized patients with units having ABC control.
T/F? Leakage radiation is an important factor when calculating shielding for primary barriers. False. Leakage is from the x-ray housing, has nothing to do with primary barrier (the detector/image-intensifier).
Which is NOT true? (…filtration does not affect beam quality of 125 keV photons? ...filtration does not affect HVL for x-rays? ...amount of filtration which reduces the intensity of radiation by 1/2 is known as HVL? ...filtration reduces beam intensity?) "does not affect HVL" is false. Filtration will increase the HVL (half value layer) by preferentially removing low energy photons in the output spectrum.
Which is NOT required on mobile fluoro equipment? ...image intensifier? ...automatic brightness control? ... device to prevent operation at source-to-skin distance of <12 in? ... device to prevent oper'n when beam is not intercepted by primary barrier? Automatic Brightness Control is not required, but everything else listed is.
What is the minimum target-to-table distance allowed for under table fluoroscopic units? 12 inches
For a fluoroscopic system with ABC and 9 inch image intensifier, changing from 9 inch mode to 6 inch mode will: ...increase minification again? ...increase size of radiation field where it enters the patient? ...decr resolution? ...incr patient exposure? "increase pt exposure": When going from a large field of view (FOV) to a small FOV, a decrease in brightness gain occurs in the II; compensation is obtained by increasing the exposure to the detector (and thus the patient).
The maximum allowable exposure to a person in a controlled area is: ...100 mR/week? ...0.01 R/week? ...1 R? ...10 mR? 100 mR/week. Not specifically covered; however, a controlled area allows 5 R/year, thus ~ 100 mR/week.
In cine-fluoroscopy, maximum magnification is achieved by: ...total overframing? ...mean diameter framing? ...exact framing? ...maximum horizontal framing? total overframing. See pg 31 Fluoro. Framing refers to the manner in which the round image is projected onto the rectangular area of the 35 mm film.
The overall statistical quality of an image intensified fluoroscopic system is determined by the ____. quantum mottle (or statistical noise, or signal to noise ratio)
Which is TRUE about "use factor"?: ...use factor is r/t time ppl spend in area? ...use factor for secondary barriers is always 1? ...use factor for primary barriers is always 1? ...use factor is not considered at all when calculating primary barriers? use factor for sec barriers always 1. USE FACTOR is fr of time radiat'n will be on barrier. Primary radn: depends on time beam is on given wall w/o other barrier (such as II), <<1. Secondary radn: (leakage/scatter) radn always hitting walls.
Which exposure rate for an overtable fluoro unit is acceptable? ...4.5 R/min at 30 cm above table top using 9 inch Lucite? ...4.5 R/min at 30 cm above tabletop using 9 inch water? ...4.5 R/min at 30 cm from the image intensifier using 7-7/8 inches Lucite? 4.5 R/min at 30 cm from image intensifier using 7-7/8 inches Lucite. Must be <5 R/min. In OVERTABLE fluoro unit, exposure is measured at 30 cm from the II when possible. A phantom that simulates a typical patient attenuation is 7-7/8" Lucite or 9" water.
Which is NOT required on undertable fluoro equipment? ...shut off when beam is not intercepted by primary barrier? ...collimators to restrict size of useful beam to < size of primary barrier? ...cumulative timer 5 min? ...0.5 mm shield for bucky slot? 0.5 mm lead shielding device for the bucky slot. A Bucky slot cover is a protective device to shield the user from scattered radiation when the undertable cassette is not used. It must have at least 0.25 mm Pb thickness (i.e., 0.5 mm is not required).
What is the maximum permissible amount of leakage radiation from a diagnostic-type x-ray tube housing? Leakage radiation must be less than 100 mR/hr at 1 meter from the tube.
Image intensified fluoroscopy allows the physician to use which of the following visual characteristics which was unusable with conventional fluoroscopy? ...scotopic vision? ...acuity? ...photopic vision? ...integration time. Photopic vision is used with image intensified fluoroscopy.
Protective aprons worn by personnel during a fluoroscopic examination where the minimum exposure rate is 5 mR/hr MUST contain the equivalent of what thickness of lead? 0.25mm is minimum lead thickness in protective aprons for all cases.
Of the following whole body occupational doses, which must be reported to regulatory agencies within 30 days? ...monthly dose of 450 mrem? ...quarterly dose of 1350 mrem? ...quarterly dose of 1200 mrem? ...yearly dose of 5 rem? quarterly whole body dose of 1350 mrem. A quarterly dose of 1350 mrem exceeds the provisions of 1250 mrem/quarter and therefore must be reported within 30 days.
What is the approximate magnitude of scatter at tableside (1-3 feet from the table) during fluoroscopy? ...50-500 mR/hr? ...50-500 mR/min? ...500-1,000 mR/hr? ...5-50 mR/hr? 50-500 mR/hr. Iso lines in Fluoro appendix show 500 mR/hr at 1 ft to 1 m from pt. Rule of thumb states 0.1 % of entrance exposure is scattered at 1 meter distance.
The statistical fluctuation for a beam of photons with 10,000 photons per square mm is ±100 (±1%). What is the statistical fluctuation for a beam of photons with 2500 photons per square mm? ...± 50? ...± 1 percent? ...± 25? ...± 10 percent? ± 50. Fluctuation about a mean number of detected photons (N) is standard deviation (SD), or sigma, which is sqrt(number of photons, or N). The % noise (% SD) is equal to sqrt(number of photons) / number of photons, or sigma/N, or SD/N.
If at 2 feet from a radiation source the exposure rate is 200 mR/hr and you remain at this location for 15 minutes, your exposure is 50 mR. What is your exposure if you stand 4 feet from the source for 12 minutes? 10 mR. At 2 feet, exposure is 50 mR in 15 minutes, or 200 mR/hr. At 4 feet, distance is doubled so exposure will be ¼ of exposure at 2 feet, therefore 50 mR/hr. For 12 minutes of exposure time, the total exposure will be 50 mR/hr * (12/60), or 10 mR.
The integration time for the human eye is: ...20 milliseconds? ...0.2 seconds? ...2.0 seconds? ...50 milliseconds? 0.2 seconds (200 milliseconds). This is why a dynamic imaging display looks less "noisy", because the eye/brain system is averaging approximately 5 frames.
If the exposure rate of 3 feet from a patient undergoing fluoroscopy at 100 kVp and 2 mA is 300 mR/hr, what is the exposure rate if the mA is increased to 3 mA? 450 mR/hr. Current (mA) output is directly related to exposure for fluoroscopic (continuous) radiation. 3/2 x 300
What is the minimum filtration requirement for fluoroscopic equipment? 2.5 mm aluminum total
The maximum allowable whole body occupational dose is ? ...500 mrem/year? ...1250 mrem/quarter? ...7.5 rem/quarter? ...400 mrem/month? 1250 mrem/quarter, or 1.25 rem/quarter, or (as stated in the syllabus and lawbooks) 5 rem/yr.
Which of the following best represents the reduction in radiation intensity for a beam of photons passing through 10 half-value layers of shielding? ...1/1000? ...1/500? ...1/2000? ...1/100? 1/1000. Roughly to (1/2)^10, which equals 1/(2*2*2*2*2*2*2*2*2*2), or 1/1024. This precisely equals 0.0009765625, but that’s not a given answer. The value 0.001, or 1/1000, approximates (best represents) 1/1024.
The recommended dose to a fetus during pregnancy for an occupational worker is: ...0.5 rem per quarter? ...0.05 rem per month? ...500 mrem per gestational period? ...5 mrem per month during gestational period? 500 mrem per gestational period. Same as 0.5 rem, or 5 mSv
The maximum permissible exposure rate to a person in an uncontrolled area is: ...0.1 R? ...100 mR/week? ...10 mR/week? ...1 mR/week? source says "10 mR/week. Uncontrolled area has general public limits which are 1/10 of controlled area (e.g., 500 mR/yr or roughly 10 mR/wk)." check this, as limit should be .1 rem/yr.
Radiation effects due to a 1000 rem whole body dose can probably NOT be reduced by: ...using a low dose rate? ...fractionating the dose? ...using neutrons instead of x-rays? ...none of the above? using neutrons instead of x-rays. The relative biological effectiveness of neutrons is much greater than x-rays (high "quality factor")
In an image intensifier, brightness gain results from: ...minification gain and contrast ratio? ...quantum sink and contrast ratio? ...flux gain and contrast ratio? ...flux gain and minification gain? flux gain and minification gain. Flux gain (electronic gain) is the gain related to the acceleration of electrons in the II. Minification gain is related to the large input phosphor "minified" to the small output.
In an image intensifier, x-ray photons are converted to photo-electrons by the: ...input phosphor? ...anode? ...photocathode? ...output phosphor? photocathode. Photo (light) cathode (source of electrons).
The ratio between the vertical resolution of a television monitor and the number of horizontal scan lines is called the ___. Kell factor
For a diagnostic x-ray system, which of the following is directly proportional to the exposure delivered to the patient? ...kVp? ...milliamperage? ...filtration? ...target-to-patient distance? milliamperage. Exposure is directly proportional to mA. It is proportional to (kVp)^2 and (distance)^2. It is exponentially related to filtration.
The major advantage of video discs over video tape is: ...better image quality with less patient exposure? ...better ability to record motion? ...random access of images? ...less physical wear? random access to images
For a fluoro system with undertable tube and ABC, moving II away from patient will: ...reduce image size of anatomic structure? ...increase size of radiation field at table top? ...reduce amount of scattered radiation into room? ...increase patient dose? increase patient dose. Inverse square law: the image will be magnified, field size at the table top will be reduced to ensure that only the input phosphor is irradiated, thereby concentrating the dose to a smaller area on the skin.
What is the maximum recommended exposure for x-ray film which is to be stored for 1 month (4 weeks)? ...0.02 mR/week? ...0.05 mR/week? ...0.2 mR/week? ...0.5 mR/week? This needs an answer. Suspect the lowest given exposure.
Which is TRUE re: shielding requirements for leakage radiation? ...max permissible leakage is 0.01 R/hr at 1 m? max contin mA must be calc'd from tube rating chart? barrier reqmts for leakage radn equal to reqs for scatter? "use" factor is calculated? the maximum continuous mA must be calculated from the tube rating chart.
A television monitor can only display 30 frames per second. Flicker is avoided in television systems by using: ...the correct bandpass? ...more scan lines per frame? ...interlaced scanning fields? ...nothing; flicker is not noticeable at 30 frames/sec? interlaced scanning fields. Interlaced scanning allows ½ of total image (odd lines or even lines) to be displayed in ½ the time (then remaining odd/even lines displayed also in ½ the time), allowing a field rate of 60/sec at frame rate of 30/sec.
If we have an f/2.8 lens and wish to change to a lens which is twice as fast (passes twice as much light), which lens would you choose? ...f/1.4? ...f/4.0? ...f/5.6? ...f/2.0? f/2.0. f/# = focal length/lens diameter, r/t lens speed or light collection efficiency. As lens diam incr, collection effic incr (i.e., lens is faster, f/# "series" incr by a factor of 2 each f/stop, related by sqr of f/#s: (2.8/2.0)^2 roughly 2x faster).
The ratio of brightness between two adjoining areas of a fluoroscopic image is called: ...contrast? ...flux gain? ...vignetting? ...brightness gain? contrast is the ratio of the intensity of one area to another adjoining area.
For a video signal, which portion of the signal is responsible for "white?" ...highest signa? lowest signal? background signal? highest signal on the curve
The biggest advantage in using a television system to view image intensified fluoroscopy rather than direct viewing is that television systems have: ...better resolution? ...less lag? ...less distortion? ...better contrast? better contrast. The television system offers the ability to vary contrast through brightness/contrast adjustment.
You are fluoroscoping a patient using 80 kVp technique. At this kVp, the intensity of the x-ray beam where it enters the patient should not exceed how many roentgens per minute for each milliampere (mA) of current? 2.2 R/min. Approximately 2 R/mA continuous at 80 kVp at the tabletop.
Image intensifier brightness can degrade up to 10% per year. Because of this degradation, a periodic check of brightness can be made by measuring: ...conversion factor? ...aspect ratio? ...contrast ratio? ...Kell factor? contrast ratio
The unit of absorbed dose is the __. rad
The central portion of an image intensifier possesses the greatest: ...distortion? ...brightness? ...magnification? ...aberration? brightness. The center area of the image has the greatest brightness and resolution. The fall-off of brightness at the edges of the field is known as vignetting. The least distortion (geometric) is also at the center.
The reduced brightness at the periphery of a fluoroscopic image as compared to the center of the image is called: ...aberration? ...refraction? ...vignetting? ...lag? vignetting. The center area of the image has the greatest brightness and resolution. The fall-off of brightness at the edges of the field is known as vignetting. The least distortion (geometric) is also at the center.
The use of an auxiliary aperture (iris diaphragm) has the following beneficial effect(s) on an Image: ...improved contrast? ...improved resolution? ...decreased spherical aberration? ...all of the above? all of the above. The aperture will help decrease scattered light in the lens, reduce aberrations by using only the central portion (also increase resolution). The down side is reduced lens speed and therefore increased patient dose.
The number of horizontal scan lines for a 19 inch television monitor compared to a 12 inch monitor will: ...depend on the Kell factor? ...increase proportionately? ...remain the same? ...depend on the make and model of the monitor? remain the same. The number of monitor scan lines is unchanged relative to the size of the monitor.
If the exposure area is doubled by opening the collimators, the patient dose and scatter to the operator will ___. double. The area irradiated is doubled, increasing the scattering cross section and doubling the integral patient dose (although the dose to any one point in the tissue will not be increased by a factor of two, but will incr d/t incr scatter).
The input phosphor of an image intensifier is composed of ___. cesium iodide
The inherent spatial resolution of a 9 inch diameter input image intensifier is approximately ___ lp/mm. 3.5 line pairs per mm
When switching from the mag mode (4.5 inch FOY) to the standard mode (9 inch FOV) with a system employing Automatic Brightness Control with mA control, the tabletop exposure will ___ by a factor of ___ times. decrease, four (half the size in two dimensions, length and width)
The typical input phosphor exposure for a 35 mm cineradiographic study using a 9 inch input phosphor diameter is approximately: ...5 R/min? ...15 mR/frame? ...100 microR/frame? ...15 microR/frame? ...1.5 microR/frame? 15 microR/frame.
The minification gain achieved by an image intensifier with a 12 inch input phosphor and a 1 inch output phosphor is ___. 144 (i.e., 12 x 12)
For "special activation" fluoroscopy, the maximum tabletop exposure permitted by the state of California Title 17 Radiation Control Regulations is ___. 20 R/min (pg 35, fluoro syllabus)
When measuring entrance exposure for portable C-arm, the ionization chamber should be positioned: ...At x-ray tube output port? 60 cm away from input phosphor? 30 cm away from the input phosphor? At the input phosphor? Depending on the SID of the C-arm? 30 cm away from the input phosphor.
A 100 mm photospot camera in the 9 inch mode of operation delivers approximately ___ microR/frame to the input phosphor. 100 microR/frame (why? I can't find this.)
The typical resolution delivered by a 525 line closed circuit television camera for a 9 inch FOV image display is ___ lp/mm. 1.0 lp/mm vertical resolution, because 525 / (9 in * 25 mm) = 2.33 lines per mm (roughly 1 lp/mm). However, ntrinsic resolution of output phosphor is 3.5 lp/mm (roughly 4).
Conversion factor is a measurement of what? image intensifier input exposure to output light gain
The purpose of the photocathode structure in the image intensifier is to ___. convert light into electrons
For a fluoroscopy system having automatic brightness control with manual kV and variable rnA, when the kV is set to a higher value, patient dose __ increases or decreases? __ and image contrast __ increases or decreases? __ . decreases, decreases
The component in the optical coupling distributor that controls the exposure incident at the input phosphor for cine or photospot film imaging is the ___ . aperture
The component in the fluoroscopy imaging chain that creates the most "image lag" is the _____. television camera
The maximum tabletop exposure allowed for a fluoroscopy system in the State of California using Automatic Brightness Control for a "standard adult" attenuator is ____. 5 R/min
Compared to a standard vidicon TV camera target, the lead oxide (Plumbicon) TV target generally has __more or less?__ lag and displays __more or less?__ image noise. less, more
Overall brightness gain of image intensifier is best described as: ...Flux gain + Minification gain? ...Flux gain divided by Minification gain? ...Flux gain x Minification gain? ...(Flux gain x Minification gain) divided by photocathode work function? Flux gain x Minification gain.
To preserve image contrast and brightness in a fluoroscopic study when panning from a thin to a thick part of the body, the automatic exposure control system should __ Increase/Maintain/Decrease?__ the kV and __ Increase/Maintain?Decrease?__ the mA. maintain, increase
For a conventional undertable x-ray tube fluoroscopy unit, the approximate tabletop exposure rate at 80 kVp is ___ R/min per mA of tube current. (0.5, 1, 2, 5, or 10?) 2 R/min per mA of current
Interlaced scanning of the TV target provides a field rate of ___ Hz and a frame rate of ___ Hz. 60, 30
For a standard interlaced TV monitor, the number of horizontal lines used in creating the TV frame is ____. 262. Interlaced creates each frame with half of the total number of lines, doubling the field rate (actual frame rate stays the same) and reducing flicker. The total number of horizontal lines on a TV image is 525. Half of 525 is 262.
A spacer attached to the x-ray tube on a portable C-arm fluoroscope must limit the minimum xray source to patient distance to ___ inches, according to Title 17 California Radiation Control Regulations. 12 inches
Scattered radiation unattenuated from the patient at a 1 meter distance during a fluoroscopy examination with a tabletop exposure of 4 R/min is approximately ___. (0.1, 0.4, 1.0, 4, or 10 mR/min?) 4 mR/min (about 1/100 of the table top exposure from primary beam)
A cumulative timer measuring fluoro "on" time must provide an audible signal every ____. (What time interval?) 5 minutes
Vignetting is best defined as: ...Geometric distortion at edges of the image? ...Image brightness loss at edges of image? ...Contrast ratio of central part ofthe image? ...Lag occurring in TV camera and causing smearing? ...Graininess across the image? Image brightness loss at edges of image.
The percentage of primary radiation transmitted through the abdomen of an average adult during a fluoroscopy procedure is ___. (1, 10 25, 50, or 80%?) 1%
For a fluoro system using Automatic Brightness Control, as image intensifier is moved closer to the patient, the displayed field of view on the monitor __increases/stays same/decreases?__ and the tabletop exposure _increases/stays same/decreases?_. increases, decreases
A "whole body dose" is considered the dose received by: ...the arms above the elbow? ...the head? ...the trunk? ...the legs above the knees? ...all of the above? all of the above.
The film badge (pick 1): ...provides protection from radiation? identifies medical personnel working with radiation? records exposure to ionizing radiation that has occurred? audibly indicates the presence of x-rays? accurately measures exposure rate? records the exposure to ionizing radiation that has occurred.
The protective curtain used on a fluoroscopy unit must have a minimum of ____ mm lead equivalent thickness. 0.25 mm lead
For room shielding, need to consider secondary radiation sources because: ...only low mA are used? drape attenuates scattered x-rays? output limit of x-ray tube from tube heat? the II serves as primary barrier? the image intensifier and housing serve as a primary barrier.
"Bucky Slot Cover" is: ... protective barrier against scattered radiation? anti-scatter grid that oscillates during x-ray exposure? protects dead-man switch? prevents exposure of film in spot-film carrier during fluoro? door access to undertable tube? a protective radiation barrier to attenuate scattered radiation.
The typical percentage of scattered radiation exposure transmitted through a lead apron is ___. 3%
The "latent period" with respect to biological effects of ionizing radiation is ___. the time between the exposure and the expression of biological damage.
The most radioresistant cells of those listed below are ___. ...gastrointestinal tissues? ...brain tissues? ...fetal tissues? ...red bone marrow tissues? ...spleen tissues? brain tissues.
One minute of fluoroscopy on a typical adult delivers at the tabletop approximately ___ times the exposure due to natural background radiation in one year. 20 times
Somatic dose indicators include all of the following EXCEPT: ...injuries to superficial tissues? ...injury to fetus during gestation? ...cancer? ... genetic changes in future generations? ...impaired fertility, life-span shortening, & cataract formation? injuries expressed as genetic changes in future generations.
The most radio-sensitive period during gestation of the fetus is ___. (weeks 0-2, weeks 2-6), second trimester, third trimester, just before birth?) the first two weeks
All of following will decr exposure EXCEPT: ...minimize “on” time? ...using "last-frame-hold”? ...keeping patient-detector distance as large as allowable? ...collimating beam to smallest field size practicable? ...using highest kVp and lowest mA possible? keeping the patient-detector distance as large as allowable.
For the highest visual acuity, the __rods/cones/pupils__ of the eyes are used with a __dim/bright__ image display. cones, bright
The supervisor/operator of a fluoroscopy unit with automatic brightness control must test the system a minimum of each ____ with a standardized phantom, and record the __ and __ in a log book. week, mA and kV
The total amount of filtration in an x-ray tube used for fluoroscopy purposes must be a minimum of ____. 2.5 mm Al or equivalent (question source says 2.0 mm aluminum, which is wrong. See fluoro page 93)
When moving one-half the distance closer to the source of radiation, the incident exposure __increases/decreases?__ by a factor of __how many?__ times. increases, 4
A dose of 1 mGy is equivalent to ___ mrad. 100 mrad (remember: 1 Gy = 100 rads, page 79 fluoro)
The approximate exposure rate due to scatter 1 meter from the tabletop is (0.2 mR/min, 2 mR/min, 2 R/min, 2 mR/hour, or 20 mR/hour?) 2 mR/min. Most closely approximates 100 mR/hr (see pg 116 of fluoro).
To preserve image resolution, the most important aspect of cine-angiography listed below for imaging of the coronary arteries is: …focal spot size? …8:1 anti-scatter grid? …magnification mode of the II? …short exposure pulse width with high mA? short exposure pulse width with high mA
Quantum sink of tuned fluoroscopy system is: ...# x-ray photons absorbed by II input phosphor? loss of contrast from veiling glare within II? lens coupling of output phosphor & loss of light? human eye capture of light from monitor? noise from TV system? number of x-ray photons absorbed by the image intensifier input phosphor
All items below are part of the x-ray tube except: ...rotating anode? ...focusing cup? ...photocathode? ...evacuated envelope? ...tungsten filament? photocathode.
The component in the image intensifier that changes the field of view from standard mode to magnification mode is the: electrostatic lenses
A CA certified supervisor of fluoro (choose any/all): ... responsible for individuals operating equipment? ensures that system is working within safe limits? comply with CA Regulations? ascertain that all working with system possess valid permits? all of the above
Biological effects of radiation are known to be influenced by all EXCEPT: ...type of radiation and dose rate? ...size of cells in tissue exposed? ...total dose received by tissue? ...type of cells in tissue exposed? size of the cells in the tissue exposed
As the kilovoltage peak (kVp) is increased and the milliampere seconds (mAs) is correspondingly decreased, what happens to patient skin exposure? patient skin exposure decreases
The greatest contribution of unnecessary radiation exposure to the patient comes from the x-ray operator's failure to: collimate the x-ray beam to the area of clinical interest only
All of following must be posted in x-ray areas EXCEPT: ...each x-ray supervisor/operator permit? each technologist certificate and fluoroscopy permit? Rad Health Dept form RH-2364, "Notice to Employees."? each physician's license for the healing arts? each physician's license for the healing arts
During a 2-minute (fluoroscopy exposure time) routine upper GI series examination, a typical x-ray exposure to the patient is: Choices are 0.5 roentgens, 1.0 roentgens, 6.0 roentgens, or 30.0 roentgens. 6.0 roentgens (based on table top exposure of 2.2 R/min per mA at 80 kVp, 2 minutes, and typical current range of 1-5 mA, which leads to range 4.4-22.0 Roentgen)
CA Radiation Control Regulations define “dose” as radiation absorbed per mass. Whole-body dose includes which of following (choose any/all that apply): Head and trunk? Gonads? Hand and Feet? Ocular lens? Blood-forming organs? Whole body? all but hands and feet (below elbows and below knees)
A film badge report expresses an individual's radiation dose equivalent in what units? rems (although question source says "rads," but that is absorbed dose, not dose equivalent. The numbers end up being equivalent, though, for x-rays where QF=1.)
CA Radiation Control Regs require that individual radiation monitoring records be preserved by employer after termination of employment of a technologist or x-ray technician for how long? …at least 1 year? at least 3 yrs? at least 7 yrs? indefinitely? indefinitely
A certain x-ray tube at a given kilovolt peak (kVp) delivers 4 milliroentgens (mR) per one milliampere-second (mAs) at 40 inches distance. At 80 inches distance, the radiation output from the x-ray tube (in mR/mAs) will be: (choices are 16, 8, 2, or 1) 1. Double the distance, cut exposure to ¼. ¼ of 4 mR/mAs is 1 mR/mAs.
If you convert 12 milliroentgens (mR) to roentgens (R), you will have: 0.012 roentgens (Don't overthink it.)
All of the following influence the tabletop exposure rate except: ...filtration? ...kilovolt peak (kVp) used? ...target-to-panel distance? ...light in the fluoroscopy room? light in the fluoroscopy room
A protective curtain should be interposed between the operator and the patient because scattered radiation exposure at 1 foot from the patient could be as high as: 500 milliroentgens (mR) per hour (see pg 116 fluoro)
What is a "dead-man" switch? one that stops when the pressure on it is released
Choose any/all that apply: usage of "boost" position or high-level fluoro: I. increases tube current and potential > normal limits. II. automatically raises table. III. continuous manual activation is required. IV. continuous audible signal is required. I, III, and IV only. Boosts current & potential, continuous manual activation and audible signal are required (does not raise table)
When a C-arm is used for AP chest view, in which direction is the most scatter? (answers might include ...45 degrees from primary beam? 90 degrees from primary beam?135 degrees from primary beam? 180 degrees from primary beam?) 135 degrees from primary beam (see page 116 fluoro). Not sure where 180 degrees fits in, but it isn't mentioned in the syllabus and in theory should be less based on compton scatter rules.
Which method of gonadal shielding is best for use during fluoroscopy? shaped, contact shielding
What is a typical setting for milliamperage (mA) during spot filming? …2? …5? …10? 150? 150. 100-150 mA during spot filming, but only 1-5 mA during fluoro.
The California Radiation Control Regulations require that tube potential (kVp) and current (mA) be monitored how often? daily (ABC checked weekly)
For mobile (C-arm) fluoroscopy equipment, inherent provisions must ensure a minimum source-to-skin distance of ____. 12 inches (30 cm)
The California Radiation Control Regulations require that the minimum lead equivalence of gonadal shielding must be: 0.5 mm lead (twice that of aprons, curtains, and the Bucky slot cover, which all need minimum 0.25 mm lead). See pg 88 fluoro, note at bottom.
What is the purpose of synchronization in CINE? to operate the camera shutters at the same frequency as x-ray pulses and thus decrease patient dose
The recognition or integration time of the human eye is the time it takes for recognition of an image. How long is this time? 0.2 sec
Which (pick any/all) of the following factors result in a brighter image being produced at the output phosphor of an image intensifier? …fluorescent material? …tungsten filament (cathode) ? …flux gain? …minification? flux gain and minification
The best description of virtual image is: ...image created by actual intersection of light rays? ...image on cine film? ...television image? ...image that cannot be projected and exists only for computational purposes? television image (see fluoro page 127 under Angular Magnification)
What is the number of horizontal lines on a standard TV monitor? 525
When switching from a 15 inch to a 19 inch TV screen, does the number of horizontal lines change? no
The mA setting for fluoroscopy is typically less than: 5 mA
Doubling the exposure time of the patient does what to the total exposure to the patient? Doubling exposure time doubles total exposure.
CA Radiation Control Regs require a cumulative manual-reset timer activated by exposure switch that produces an audible signal and temporarily interrupts x-ray beam when fluoro time has exceeded a predetermined time limit of no more than how long? 5 minutes
Post-1974 fluoro equipment EQUIPPED WITH automatic exposure controls (AEC) shall not be operable at any combination of tube potential and current which will result in skin exposure rate from primary/useful beam in excess of ___ roentgens/minute. 10.0 R/min. Page 40 fluoro, bottom paragraph.
Post-1974 fluoro equipment WITHOUT automatic exposure controls (AEC) shall not be operable at any combination of tube potential and current which will result in skin exposure rate from primary/useful beam in excess of ___ roentgens/minute. 5.0 R/min. Page 41 fluoro, top paragraph.
Genetic dose refers to: effects exhibited in future offspring of persons who have been irradiated
National Council on Radiation Protect'n and Measurements (NCRP) in their report Medical Exposure of Pregnant and Potentially Pregnant Women states that risk to the embryo/fetus is significantly increased above control levels only at doses above ____ rad. 15 rad
The largest percentage of exposure to the population from man-made radiation comes from which source? medical
During fluoroscopy procedures utilizing television (vidicon) cameras, why does blurring or lag of the image occur as the camera is moved during the procedure? It takes a certain amount of time for the image to build up and decay on the vidicon target.
During fluoro, the Bucky tray is moved to the end of the exam table, leaving an opening in the side of the table approximately 2 inches wide at gonadal level, which must be automatically covered with at least what thickness of lead (or equiv)? 0.25 mm lead
All of the following affect patient exposure except: ...three-phase generators? ...collimation? ...target-to-panel distance? ...exposure time? three-phase generators don't affect patient dose, but they have advantages of relatively high mA available, high effective kV, and near constant potential
A "high radiation" area is any area, accessible to individuals, in which there exists radiation at such levels that an individual could receive in anyone hour a dose to the whole body in excess of how much? 100 millirems, same as 0.1 rem (this is for “high radiation” area. Bonus: what is a “radiation area” limit? 1/20 of this.)
The SI unit which is analogous to the rem is the ___. Sievert
Define half value layer (HVL). thickness of a specified substance which reduces the exposure rate of the primary beam by one-half (NOT “the patient thickness where one-half of the primary beam has been absorbed”)
A cardiac catheterization examination with 10 minutes of fluoro and 1 minute of cine will deliver an approximate entrance skin exposure of _______ Roentgen. (1, 5, 100, 2000?) 100 R. Assume 5 R/min for fluoro and 50 R/min for cine.
What is the approximate dose a patient would receive during 5 minutes of fluoroscopy? ...1-3 rads? ...10-30 rads? ...40-60 rads? ...>60 rads? 10-30 rads. Remember <5 mA for standard fluoro (usually lower, 1-3 mA), and 2.2 R/min tabletop exposure per mA at 80 kVp, and rads and Roentgens values roughly equivalent for x-rays.
If an upper GI examination of a pregnant patient resulted in a total skin exposure of 5 roentgens, what is the approximate dose to the fetus? ...10 millirads? ...100 millirads? ...1,000 millirads? ...10,000 millirads? 1,000 millirads, or 1 rad. Assume HVL=5 cm in tissue, fetus roughly 10-15 cm deep. 5 R after 2-3 half-value layers ==> 2.5, 1.25, 0.6125 rads ==> closest values is 1. Roentgen roughly equivalent to rad for x-rays as far as VALUES are concerned.
During a CINE exam in which 35 mm film and a frame rate of 30 frames/second are utilized, what is the approximate skin exposure rate? ...1 roentgen/minute? ...2-5 roentgens/minute? ...5-10 roentgens/minute? ...10-20 roentgens/minute. 2-5 R/min. (Why? Not clear.)
What is the approximate dose to a patient's gonads resulting from a barium enema exam? ...10 millirads? ...100 millirads? ...500 millirads? ...1,000 millirads? 1,000 millirads. Same as 1 rad. (Why? Sketchy questions.)
What is vignetting? decrease in light intensity at the periphery of an image (NOT “the brightness ratio of the periphery to the center of the output intensifying screen”)
If a protective apron of 0.25 mm lead is worn, what is the typical exposure REDUCTION beneath the apron? 97%
The best protective eyewear for the operator to utilize during fluoroscopy is: ...polaroid sunglasses? ...lead glass contact lenses? ...lead glass eyeglasses? ...wraparound (side panel) lead glass eyeglasses? wraparound (side panel) lead glass eyeglasses
What is the definition of a filter? “a material placed in the useful (primary) x-ray beam to absorb preferentially the less penetrating radiations”
A strong correlation exists between the incidence of leukemia and the mean radiation dose received by the _____. …gonads? …thyroid? …bone marrow? …skin? bone marrow
Stray x-radiation which comes from the x-ray tube housing is called: leakage radiation
All of the following are types of personnel monitoring devices except: …geiger counters? …pocket ion chambers? …thermoluminescent dosimeters (TLDs)? …film badge? geiger counters
The “useful” or “primary” beam is defined as: radiation which passes through the x-ray tube window, aperture, cone or other collimating device
All fluoro and x-ray tubes must have “diagnostic-type tube housing,” meaning the housing must limit leakage radiation at a distance of 1 meter from the target to no more than: 100 milliroentgens (mR) in 1 hour (roughly equivalent to 100 mrad/hr for x-rays)
For both fluoroscopic and radiographic mobile equipment, inherent provisions must be made so that the equipment cannot be operated at less than ___ source-skin distance. [6 inches (15 cm)? 12 inches (30 cm)? 18 inches (46 cm)? or 24 inches (61 cm)?] 12 inches or 30 cm source-skin distance.
An instrument used to measure film density is a _____. densitometer
An instrument used to expose film to precisely controlled steps of increasing light intensity is a ____. sensitometer
A device which is made up of different density filters shaped in a step-like form where each step or filter differs in density by the square of the root of 2 is called a _____ . step-wedge (or penetrometer)
Skin entrance dose of a CXR is ___. 20 mrads (0.02 rad)
Best gonad shielding for upright XR shaped contact shield with support
Spidering artifact on a developed film caused by ____ . Static electricity
Automatic Brightness Control is QC’d how often? How long must the QC logs be kept? weekly (page 69 fluoro). Keep logs for 3 years.
What is the term for a graph of film photographic density against logarithm of radiation exposure or dose? Characteristic curve, also known as an H & D curve.
Which cell type is most sensitive to radiation? lymphocytes
What is increased density seen on unexposed film due to? base + fog. Optical density of film due to its base density plus any action of the developer on unexposed silver halide crystals. Can be measured by passing unexposed film through the processing cycle and measuring optical density with densitometer.
What are some causes of different artifacts on x-ray films? poor screen contact, light leak in the darkroom, static electricity, chemical artifact, storage fog, etc.
Grid increases or decreases patient dose? increases patient dose (stops some of the useful xrays)
Deliberately subjecting person to primary radiation for the purpose of teaching is allowed when? only with an order and if it is indicated
If an operator had 500 mrem reading on his badge in one month what does that mean? …Bad x-ray practice? …wrong location? …inaccurate reading? Bad x-ray practice. This will lead to an annual dose of 6 rem if continued.
Somatic indicators include what? Any biologic radiation effects not having to do with genetic indicators (effects on reproductive cells passed through to progeny)
Time it takes for the eye to recognize an image is defined as integration time
What is meant by whole body dose? everything except below knees, and distal to elbows
True or False: ALARA is based on the principle that no radiation dose is safe. true
X-rays passing through cell does everything EXCEPT: …damage cell irreversibly? …damage cell but able to be repaired/reversed? …interact but cause no damage? …pass through cell unaffected? all of these
Contrast media works by ___. …compton scatter? …photoelectric effect? …attenuation? photoelectric effect
The main reason for using gonad shielding is... reduce birth defects, genetic effects of radiation (which can be passed through multiple generations if mild enough not to be selected out). pg 50 radiogr
How should you handle film? …holding at an angle? …clean hands? …at the corner? all of the above
Which of the following (air, bone, fat, water) attenuates by photoelectric effect the most? bone
True of false: Smaller field size causes increased scatter radiation. False. It decreases exposure, thus decreasing scatter radiation.
What causes film fogging? Old or contaminated processing solutions, exposure to chemical fumes, faulty darkroom safelight, and/or scatter radiation.
What causes the most retakes? error in exposure factors cause 50% of retakes, (next is positioning errors, for 25% of retakes). pg 32 radiogr
Where does one properly put the caliper to measure thickness? at the center of the proposed beam
What conditions are films best stored in? …vertically or flat? …room temp? …humidity? vertically, temperature 60-70 degr F (15-21 degr C), humidity 40-60% to avoid static or sticking, free from chemical fumes and radiation
True or False: Film speed does not influence patient exposure. Focal spot size does not influence patient exposure. False (film speed DOES influence pt exposure), and True (I think, but could not find reference). Focal spot size affects image resolution. However, focal spot to film distance definitely affects pt exposure. pg 30 radiogr.
Which is responsible for density on unexposed film? choices include base + fog, fog, etc. base + fog. Base, you can't do anything about (unexposed film isn't perfectly clear). Fog, you can.
photoelectric effect and compton scatter (pg 27 of syllabus) Know it.
What are the four factors that determine the quantity of scatter radiation? Kilovoltage (kVp), Part thickness, Field size/area exposed, Tissue density. (pg 28 radiogr)
Most common reason for retakes is ___. errors in exposure factors are #1, then positioning errors. pg.32
Biological effects of radiation (Which is NOT true? can pass through cell, kill the cell, damage the cell but can be repaired, cause permanent damage, never passes through cell without causing damage) "never passes through cell without causing damage" is NOT true. If some x-rays didn't pass through unaffected, radiology would only consist of MRI and U/S.
True/False: Infertility is a long-term effect of radiation exposure. False. See pg 48 for more.
Know which cells are most affected by radiation -lymphocytes v granulocytes v stomach v brain v myeloblasts... (myeloblasts vs lymphocytes?) lymphocytes. See pg 47. The term "myeloblast" does not appear anywhere in either syllabus. Never mind the logic that would indicate that myeloblasts are more susceptible than mature lymphocytes.
Best way to reduce operator exposure to primary beam is (wear apron vs stand behind primary barrier vs collimate) Collimate? NOT "stand behind primary barrier." Look for "Keep your fingers out of the beam."
With film badge, why do they use different density filters? to allow calculation of exposure regardless of energy or type radiation. pg 56 radiogr
What to do if patient receives 6 rems of radiation within a 24 hr period? Contact State within 24 hours by telephone and “prompt” written confirmation. pg 68
What to do if employee has badge showing 150 mrem exposure for a month? choices are poor operator and supervisor practice vs. inaccurate reading vs improper placement on body vs ...? Keep employee aware, but 150 mrem/mo (or .15 rem/mo) is within 5 rem/yr WB dose equivalent if continued for 12 months. (would be 1.8 rem)
What to do if employee has badge showing 500 mrem exposure for a month? choices are poor operator and supervisor practice vs. inaccurate reading vs improper placement on body vs ...? Inform employee and make necessary changes in practices. This is on track to surpass 5 rem/year. (would be 6 rem over 12 months)
QC requirements: Which of these require daily QC? Sensitometer, densitometer, tank, developer, fixer, etc all of above. pg 96 radiogr
What is the name for the device that automatically terminates exposure when the required film density has been achieved, by measuring the amount of radiation which has reached the film? phototimer
What is the definition of attenuation? scatter + absorbed radiation. pg 115
What is the difference between "base density" vs. "base + fog." Base+Fog: optical density of film due to its base density PLUS any action of the developer on the unexposed silver halide crystals. Measured with unexposed film through processing cycle and measuring optical density with a densitometer. See pg 116 radiogr
What is the organ weighting factor for gonads? 0.25 for gonads. see pg 131 radiogr, pg 152 fluoro
How does chemical artifact appear on the film? (dark spots, bright spots, bright streaks?) Light/bright spots are from from developer solution or cigarette ashes. See page 19 radiogr
When should the badge be worn? (all the time, all the time at work, only when x-raying) must be worn only when on the job, and the equipment (device) should be stored in a safe place at the X-ray facility. pg 55 radiogr
When the tech is a patient, should the badge be worn? No. Take it off and store away from exposure for the exam as a patient.
What is the % absorption of 0.25 mm Pb apron (i.e., what fraction of incident radiation is absorbed)? 97% for 0.25 mm Pb; at 0.5 mm Pb, goes up to 99%
Whole body dose includes all except (head, gonads, trunk, below elbows and knees, above elbows and knees) below elbows and knees
What is remnant radiation? non-interacting and small-angle scattered photons which carries the x ray image (post-patient radiation that hits the detector, makes image). pg 13 fluoro.
Biological effects from radiation follows a ____ model. (nonlinear nonthreshold, linear threshold, linear nonthreshold, nonlinear threshold) linear nonthreshold. pg 62 fluoro
Which of the following is a unit of dose equivalent? (rad, rem, gray, erg) rem
What is the lead curtain for? protect imager from scattered radiation from the patient
Which of the following is the reason why 18 inches is better than 12 inches for the TPD (Target to Panel Distance)? (increased magnification, increased radiation dose, decreased radiation dose) decreased radiation dose. "For the same fluoroscopic screen brightness, patient dose can be reduced if the target to skin distance is increased" (pg 31 fluoro)
What is the best gonad shield for an upright KUB? Shaped contact shield within an athletic supporter
What is the minimum gonad shield required in California? 0.5 mm Pb equivalence
How thick must a Bucky Slot Cover be? 0.25 mm Pb equiv (Fluoro 43)
The lead curtain is for what? (protect patient, protect operator, prevent backscatter) protect operator
How are film badges read? (luminescence vs detection of ionizing radiation). Neither of these. Simple film, covered by various filters. Exposure pattern determines type of radiation. pg 72 fluoro
Which of the following is related to HVL? (Time, Distance, Shielding) shielding (not distance). Shielding is based on exponential attenuation. Distance is based on inverse square law.
Which does not cause fog (light, ionizing radiation, spoiled developer, sliding film against film or the cassette) sliding film against film or the cassette causes more localized artifact than fog. pg 95 Radiography
What happens when humidity is too low (below ideal 40-60% range)? Static electricity and spider artifact (Radiogr 95)
When should you QC processor with sensitometer/densitometer? daily before processing patient films. pg 96 radiogr
When is radiation being sent during an exam (when the deadman's switch is depressed, or when the deadman's switch is depressed and up to a minute afterwards?) only when the deadman's switch is depressed
What is the advantage of video disc recording? last frame hold (decreased patient dose up to 95% reported by manufacturers), random navigation
Details of x-ray focal spot, implications of small versus large. large focal spot reduces resolution, but size is limited by heat build up. Low mA fluoro can utilize a smaller focal spot.
Lower-end limiting factor for x-ray dosing? (IOW, why not use a lower radiation dose?) Quantum mottle (noise) is lower limiting factor.
How does cineradiography dose compare to fluoro? 10x the dose. See pg 12 fluoro.
What are the lead shielding values (thickness) for gonad shield? gloves? aprons? Bucky cover? drapes? All are 0.25 mm EXCEPT 2 things: gonad shield and gloves (both 0.5 mm)
horizontal resolution & bandwidth? #dots on each scan line. Bandwidth, a.k.a. bandpass, refers to total # cycles/sec for TV display, equal to product of # scan lines, frame rate, and the frequency rate. Usually matched to vertical resolution, which is # horizontal scan lines. pg 27 fluoro
Advantages of using higher kVp technique? more beam throughput, can therefore reduce mA for lower skin entrance dose. Disadvantage: lower contrast resolution.
What is a characteristic curve or H&D curve? type of input-output curve used to express the change in density with the change in radiation dose of the photographic or X-ray film, graphically demonstrates relationship between photographic density and radiation dose. pg 117 radiogr
know all the values when you have to report to Radiogic Health Branch at 24 hours or immediately? Report within 24 hrs: WB dose equiv >5 rem in 24hr period (or eye 15 rem, or skin
all dose limits for occupational and public? look up
Which are the most affected cells in bone marrow? lymphocytes
Know film badges, TLD's basics look up
Regarding the graphic on isoexposure curves? 500 mR/hr at 1 meter . page 116 in fluoro
results of chemical spills on films? look up
spidering artifact caused by? static electricity
In what conditions are films best stored? vertically, room temp 60-70 degr F, humidity 40-60%
How does focal spot influence rate of exposure? Focal spot has heel effect on primary beam. Anode side of beam has lower intensity d/t angled anode, shallower angle of xrays emanating from anode. Cathode side of beam is more intense. Use weaker heel (anode side) for thinner part of body.
how does film speed affect rate of exposure? faster film reduces amount of radiation needed.
when is it ok to expose a patient to xrays? (a. never b. wrong answer c. wrong answer. d. only when there is a medical indication and a doctors order only when there is a medical indication and a doctors order
The typical entrance skin exposure for a chest x-ray is closest to ____ mR. Choices are 1, 3, 5, 15, 150. 15 mR (use rule of 2s and 10s, ie, 20 mR for CXR, 200 mR for AXR or annual background, 2000 for CT or (per min) for fluoro, 20,000 per min for cine.
A chief advantage of a 3-phase or high frequency generator design is: (higher voltage ripple? ...higher effective kV? ...longer exposure times? ...smaller HVL for the same kV?) higher effective kV
The fetus of the “declared” pregnant radiation worker is allowed a dose of ___. 500 millirem throughout the pregnancy
ALARA stands for _____. as low as reasonably achievable
The three basic principles used in protecting oneself from radiation exposure are ____. time, distance, shielding
The typical half-value-layer (HVL) of an x-ray tube operated at 80 kVp is closest to____ mm Al. (choices are 0.5? …2.5? …5.0? …10.0? …20.0?) 2.5 mm Al stops about half the photons of 80 kVp x-rays. (preferentially the low energy photons, unlikely to pass through patient and provide diagnostic information)
The ALARA concept is based on the assumption that ___. (…only a large radiation dose can be harmful? …any radiation dose can have some adverse effect? …a little radiation dose can be beneficial? …there is a threshold dose for stochastic radiation events?) any radiation dose can have some adverse effect
A radiation worker is required to be monitored if ____. (…he/she operates mobile x-ray equipment? …he/she wants to be? …the annual radiation dose is likely to be greater than 10 millirem? …any radiation is present in the workplace?) he/she operates mobile x-ray equipment (the other mandatory group is anyone entering a "high radiation" area.
A 0.25 mm lead equivalent apron will reduce scattered x-rays by ____%. 90% was highest answer in practice question (sure it's not 97%?)
Anyone who must remain within 6 feet of patient or x-ray tube during radiographic exposure must ___. (…sign waiver? …wear radiation monitoring badge? …be protected by whole body apron of at least 0.25 mm lead equivalence? …stand behind another person?) be protected by a whole body apron of at least 0.25 mm lead equivalence
Mechanical restraining or supporting devices should ____. (…never be used? …be tested daily according to state regulations? …should be used instead of a human holder whenever possible? …be outlawed?) should be used instead of a human holder whenever possible
If x-rays are to be taken of a potentially pregnant patient, technologist should NOT __. (…ask patient of her prego status? …ask rad if procedure involves abdominal area? …shield pt's abd region with at least 0.25 mm lead before taking extremity film?) All of the above. Tech should NOT "perform the examination without regard to pregnancy."
Radiation is useful in medical diagnosis because ____. (…of its ability to cause biological damage? …of its ability to penetrate tissue? …lead walls can absorb it? …it is easy to get a radiation-use license?) of its ability to penetrate tissue
When operating mobile radiographic equipment, the x-ray equipment operator should stand ____. (…within touching distance of the patient? …adjacent to the x-ray device? …at least 6 feet from the patient? …behind the ICU nurse?) at least 6 feet from the patient
Which of the following is a measure of radiation dose in the human body? (…Curie? …Roentgen? …rem? …mR/hr?) rem
Radiation workers are allowed whole body radiation doses of _____ millirem/yr. 5000 millirem/yr (= 5 rem/yr)
Patient skin dose for a CT scan acquisition of the abdomen (single acquisition of 20 consecutive slices) is closest to ____ millirads. (3? …30? …300? …3000? …30000?) 3000 millirads (same as 3 rads, which is similar to 3 rem (30 mSv) given the quality factor of 1 for xray photons)
Filtration must be at least ____ mm Al equiv. at least 2.5 mm Al is required (should be 3.0 mm).
How much lead equiv barrier is required around the II enclosure? (primary barrier) 2 mm lead
Scatter at 1 foot from patient could be up to ____ mrad/hr. 500 mrad/hr. pg 69 fluoro
Routine fluoro must not exceed ____ R/minute, except when using ABC, using mag, or when recording where higher exposure rates are allowed. 5 R/min
Curtain/drape is --or is not?-- req’d on C-arm system? is NOT required on C-arm. Think IR procedures.
What happens at the input phosphor? xray converted to light photons (immediately captured by photocathode)
Photocathode does what? converts photons into electrons, which are sped up by the accelerating anode and focused by electrostatic lenses
What happens at the output phosphor? electrons converted to light photons, for direct view by eye (no longer allowable by law), by mirror, or video camera
Image magnification occurs how? in the II by the electrostatic lenses by higher voltage applied, causing crossover to occur closer to photocathode, so final image on output phosphor is magnified. Resolution may increase from 4 lp/mm to 6 lp/mm.
Higher f-number of lens means ____ . less light available to make an image (slower lens)
Video tape disadvantages/advantages? poorer image quality and fixed frame rate of 30 per sec, but instant replay available and exposure not increased.
1:8 grid is high ratio or low ratio? low ratio
Remnant radiation is ____ . low-angle scattered or noninteracting “post-patient” photons, roughly 1-5% of incident primary beam xrays, forms the image.
Minimum xray source-to-skin distance must be ____ . "Shall" be no less than 12 inches (30 cm). "Should" be 18 inches (45 cm).
High frequency and 3-phase x-ray source advantages (over single phase)? high effective kVp, higher mAs available, more constant voltage (less pulsatile).
Tungsten target is anode or cathode? target is anode. Cathode is electron source also made of tungsten coil, heated.
Aging of input and output phosphors can lead to up to ____% loss of brightness gain (flux gain * minification ) over the course of a year. 10% loss over a year. Check by checking conversion factor.
Light intensity at output phosphor in candelas (cd) divided by input exposure in mrad/sec gives you ____ . conversion factor
F-number is measure of ___ . aperture. Smaller aperture means higher f-number. Also related to lens diameter (analogous to aperture), and focal length (lower focal length ==> lower f-number). =focallength/diameter
(normal mode size)^2 / (mag mode size)^2 = ? relative increase in patient dose with mag c/t no mag
Contrast ratio ratio of brightness of full exposure to blocked exposure (behind lead disk). Usually 15:1 for most modern IIs.
Limiting resolution of a system is defined as ____ . the value in lp/mm at an MTF of 1. (Modulation Transfer Function)
Is cesium iodide better than zinc cadmium sulfide? for what? yes (for input phosphor, higher efficiency of x-ray capture/conversion)
What is the term for light scatter in the output window of the image intensifier and its effect on background signal and reduced image contrast? veiling glare
vertical resolution # horizontal lines across object or screen / (2*diameter of object or screen in mm)
Kell factor ratio of vertical resolution to number of scan lines.
typical Kell factor ~? 0.7, or 70% vertical resolution, equal to 367/525 lines
types of camera systems? vidicon (has lag), plumbicon (no lag, but more quantum mottle or noise because of less temporal averaging), image-orthicon (too expensive for wide use), and charge-coupled device (CCD, better, replacing old vidicons, solid state semicondctr, no lag).
video tape pros? no intermediate processing so available for instant replay, and no increase in radiation dose
video tape cons? relatively poor image quality c/t cine film, and fixed frame speed of 30 fr/min.
cine film comes in 35 mm and 16 mm. 35 is higher quality but more radiation needed. To what degree is cinefluorography higher in radiation dose to the patient and operator? 10x higher dose than regular fluoro.
cine framing frequency in range of 7.5, 15, 30, 90, 120, all divisions of 60. Faster framing used for pediatric coronary angio.
T/F: Radiation dose is directly proportional to framing frequency in cinefluorography True
Lower f-number means what? more light reaches imaging plane, faster lens, shorter focal length or distance b/t lense and film, larger diameter of lens. focal length / lens diameter (both in mm)
When diameter of circular fluoro image is smaller than smallest dimension of the film frame, this is called ____ . underframing
When diameter of circular fluoro image is same as smallest dimension of film frame, this is called ____ . exact framing (only 58% of cine film is used)
When diameter of circular fluoro image is larger than shortest dimension but not larger than diagonal measurement of film frame, this is call ____ . overframing (part of fluoro image is lost, must be collimated to eliminate unnecessary dose to patient)
When diameter of circular fluoro image is equal to or larger than diagonal measurement of the frame, this is called ____ . total overframing ==> more wasted fluoro image and dose to patient (unless collimated down)
Manufacturers report up to ____% reduction in dose using video disc recording during fluoro (due to image-hold capability). 95% reduction. Still, standard film-screen radiography offers better image quality at similar dose, and should be used in lieu of fluoro whenever possible.
Advantages of digital photospot imaging are ____ . instant playback of images, and possible subsequent image enlargement
Disadvantage of digital photospot imaging is ____ . lower resolution than film
Pulsed fluoro has what effect on radiation dose? reduces patient dose, with cost of lower temporal resolution.
High level (boost) fluoro 10 to 20 mA, up to 40 mA. Entrance dose is 2-10x higher than conventional fluoro, 10-50 rads/min at tabletop.
How much radiation does it take to cause erythema? several hundred rads
Since 1994, max allowable tabletop dose rate of ____ without using recording devices such as videotape. 20 rads/min
Boost fluoro requires _____. special activation with additional person, audible signal during use, no more than 20 rads/min unless recording
Collimation must be adjusted so that _____. unexposed border is visible when screen carriage is 14 inches above tabletop and collimators fully open. pg 38 fluoro
Define integral dose. product of energy absorbed (rad) and mass of tissue (gm), in gram rads. 1 gm rad equals 100 ergs.
Minimum filter 2.5 mm Al or equivalent. "Since normal voltages for average adult vary 80-120 kV, this requirement may be assumed met if HVL is not less than 3.0 mm Al." pg 39 fluoro
Intensity of xray beam at tabletop shold not exceed _____ rads/min for each mA of current at 80 kVp. 2.2 rads/min. pg 39 fluoro
Cumulative manual reset timer no more than 5 min, produces audible signal, interrupts x-ray beam
With ABC, operator must monitor current and potential every __interval?__ with phantom, keep a log __for how long?__. Health/medical physicist must monitor __how often?__ (or __how often?__ without ABC), and after repairs. weekly, 3 years, yearly, (3 years without ABC)
Cine exposure rates must be monitored by qualified person how often? yearly and after repairs. pg 41 fluoro
Photopic visual acuity is ____x greater/lower than scotopic visual acuity. 10x greater visual acuity for daylight vision over low light vision
Normal viewing distance for the eye? 12-15 inches
Upper limit of attenuation for tabletop (or cassette front panel) in mm Al equivalence? 1 mm Al equivalent
Shaped contact gonad shield 0.5 mm lead reduces dose ____%. 97% (remember, this is against the primary beam, which is high kV (effective), unlike scatter which is lower in kV (effective). That's why it still only attenuates 97%, similar to fractional attenation of 0.25 mm apron against scatter.
Photospot film camera recording requires _____ percent less radiation per image than regular spot filming. 20-50% less radiation
Brightness and contrast gain of image intensifier must be tested at least how often? at least annually
Law of Bergonie and Tribondeau w.r.t. children Children more sensitive because mitotic rate is higher, more cells in proliferative phase, more undifferentiated cells.
What cells are most radiosensitive? Lymphocytes (B cells and T cells) are affected most severely by radiation.
Which have high marrow dose?: CXR, BE, UGI, abdominal angio. BE, UGI, abdominal angio (all around 100x that of a CXR)
Spermatogonia (sperm precurors) are ________ radiosensitive. Mature spermatozoa are _______, so fertility ___is or is not___ impaired until several weeks later. Full fertility _____. severely, radioresistant, is not, usually returns
Oocytes in ovaries are __radiosensitive or radioresistant?__. radiosensitive. Radiation can cause lasting reduction in reproductive potential for young women.
Personnel dose equivalent monitoring must be recorded in rems or mrem, and recorded in ____, and preserved ____. rem/hr or mrem/hr; indefinitely. Most other records must be kept for 3 yrs.
Possibilities of radiation exposure to cell include (4): no interaction (pass-through), fatally damage cell, damage cell with full repair/reversal, damage cell with incomplete repair and perpetuation of damage to progeny
Observed changes in cells from radiation damage? chromosomal breaks, chromatin clumping, giant cell format'n, abnormal mitoses, incr cytoplasm granularity, nuclear disintegration, changes in motility or cytoplasmic activity, vacuolization, altered protoplasmic viscosity, changes in membrane permeability
Law of Bergonie and Tribondeau Radiosensitivity depends on # of undifferentiated cells, degree of mitotic activity, and length of time cells stay in active proliferation
Most sensitive cells lymphocytes or WBCs, then RBCs and granulocytes, then epithelium, then endothelium, then connective tissues, then bone cells, then nerve cells, then brain cells, then muscle cells (pg 64 fluoro)
Radiation induced cataracts can or cannot be differentiated from other types of cataracts? Radiation-induced cataracts CAN be differentiated from other types. But there are no other unique diseases associated with long term effects of radiation. (pg 64)
The most frequently occurring radiation-induced cancers are ____ . #1: female breast cancer. then thyroid (esp women and young kids), then leukemias/hemopoietic cancers, then lungs, GI, with bones at the bottom of the list. Pg 65 fluoro
Check ABC current and potential (mAs and kVp) how often? Keep log for how long? every week. 3 years.
TLD vs film badge? TLD is thermoluminescent dosimeter, lithium fluoride chip, not a permanent record, clears after “read out,” more accurate than film badges (9% error, vs 25% for film)
What is required for a monitored employee?: film badge? TLD? pocket ionization chamber? audible warning device? Film badge or TLD must be used. Others (pocket ionization chamber or audible warning device) may be used in addition.
Where can a personal dose monitor be used with respect to a lead apron? Film badge or TLD must be worn outside (on top of or above) the lead apron.
“Whole body dose” does NOT include what part(s)? arms distal to elbow, legs distal to knee
Maximum permissible dose equivalent (MPD) for occupational, per year? Total/whole body is 5 rem/yr (or 0.05 Sv, or 50 mSv, 50x the general population MPD), shallow-dose (skin/extremities) is 50 rem (or 0.5 Sv, or 500 mSv, 10x the total body MPD), and eye/lens dose is 15 rem (or 0.15 Sv, or 150 mSv, 3x the total body MPD).
Call State within 24 hrs and written notice promptly for what level of over-exposure? over annual the dose limit within a 24 hour period.
Call State immediately and written notice within 24 hrs for level of over-exposure? more than 10x the annual dose limit within a 24 hour period (a big, big deal)
Minors working in radiation area (such as a 16 yr old with parental permission and a summer job in a lab) have a different annual occupational dose limit. What is it? same as max allowable dose limit for a declared pregnant woman for entire pregnancy, i.e. 10% of the adult dose limits, i.e. 0.5 rem or 5 mSv for total body dose max (3x that for eye, and 10x for skin/extremities)
Hourly dose limit for general population (i.e., nonmonitored, assumed nonradiation area)? Hourly? No more than 2 mrem/hr (0.002 rem/hr, or 0.00002 mSv/hr). The annual projected dose limit is 1/50 of occupational annual dose limit, i.e., 0.1 rem/yr or 1 mSv/yr or 0.01 Sv/yr (all equivalent).
“Radiation area” dose equivalent limit? Remember 0.005 rem/hr. At 30 cm (1 ft), any dose above 0.005 rem/hr, or 5 mrem/hr, or 0.05 mSv/hr, or 0.00005 Sv/hr (all equivalent) deems the area a "radiation area."
“High radiation area” dose equivalent limit? Remember 0.1 rem/hr. "High radiation” has 20x higher exposure rate than “radiation” area, i.e., at 1 ft (30 cm), dose above 0.1 rem/hr, or 100 mrem/hr, or 1 mSv/hr, or .001 Sv/hr.
All aprons, drapes, curtains, Bucky Slot Cover, and other barriers against scattered radiation must be at least what thickness of lead (or equivalent)? 0.25 mm lead. What needs to be higher? Gonads and gloves.
Gonad shields and gloves (exposed or potentially exposed to primary beam) must be what thickness of lead (or equivalent)? 0.5 mm lead. Double that required by the feds. Pg 88 fluoro.
1 rem is how man mSv? 10 mSv is same as 1 rem
What is the maximum monitoring period (minimum frequency) for monitoring in California? CA does not set a min or max. Once per month is advised. Some do quarterly (such as?)
What kind of abnormally high reading does not need to be reported to CA Rad Hlth Branch? None. All overexposures must be reported, and are assumed to be result of poor working practices of supervisor and operator (bad).
Who must be monitored regardless of likely exposure? Anyone entering “high radiation area” and anyone using mobile xray equipment. All other monitoring reqs are based on supervisor’s consideration of risk to employee, with attn to USDHEW “Medical Radiation Information for Litigation”. Pg 75.
100 rems is how many Sv? 1 Sv is same as 100 mrem.
What does "dose rate" mean? rems/hr. What is “absorbed dose rate,” then? rad/hr
Occupational maximum permissible dose equivalent (MPD) for pregnant woman? 0.5 rem (5 mSv), beginning at time of WRITTEN declaration of pregnancy status, and for the entire course of pregnancy. No more than 1/10 of that in any one month (i.e., no more than 0.05 rem/month or 0.5 mSv/month)
Max dose to fetus/embryo for undeclared pregnancy? same as max dose for minor, and same as entire pregnancy dose for pregnant woman. Once declared, EMBRYO/FETAL dose cannot exceed 0.05 mrem (1/10th undeclared limit) for remainder of pregnancy
Best gonad shield for fluoro? Athletic support with a “shaped, contact” shield. Must be 0.5 mm lead for CA.
Primary (useful) beam exposure limits? Fluoro without AEC shall not exceed 5 rads/min except with "boost" activation. With AEC: may not exceed 10 rads/min except with boost. See pg 40. Pg 94 is confusing, but I think it means WITH AEC, up to 10. WITHOUT AEC, just 5.
When can radiation dose rate from primary beam exceed 10 rads/min? never for standard fluoroscopy. Boost can go up to 20 rads/min (manual activation, audible signal) if not recorded, even higher if recorded.
When can radiation dose rate from primary beam exceed 5 rads/min? Only with high level activation on systems with AEC (and high level activated, with continuous manual activation and audible sound)
Leakage radiation cannot exceed what level? 100 mrad/hr at 1 meter (for diagnostic housing)
Phantom for measuring exposure rate? must be 9 inches H2O or 7.9 inches Lucite to simulate patient
Protective lead aprons when? If one is likely to receive 5 mrads/hr or more.
Penetrometer is what? aluminum step-wedge
Highest exposure from scatter is from angle ____ degrees, zero being in line and direction of xray beam (post-patient). 135 degrees, higher than 120 degrees, all of which are much higher than 90, 60, 45, and 30 degrees. Exposure rate increases then as the primary beam is approached (not scatter anymore).
Lowest exposure from scatter is from angle ____ degrees, zero being in line and direction of xray beam (post-patient). 45 degrees (then 60, then 90). However, at 30 degrees, intensity goes up and sharply rises as you approach zero degrees (in line with primary beam, not scatter).
Dose to operator at 1 foot from patient is as high as ____ without protective curtains and Bucky slot cover. 500 mrad/hr
R is abbreviation for what unit? Roentgen (not rem, not rad). Measure of ionization (actually "charge liberation"), not of energy deposition.
What to do if (patient? worker?) receives 6 rems of radiation within a 24 hr period? contact state in 24 hours, prompt written confirmation, pg 68.
Most common reason for retake exposure control setting issues, positioning error, pg. 32
Biological effects of radiation? it can pass through cells, kill cell, damage the cell but cell can be repaired, cause permanent damage, pg 45.
Best way to reduce operator exposure to primary beam is ____ ? wear apron vs stand behind primary barrier
Why do film badges use different density filters? to allow differentiation of exposure to energy radiations, pg 56.
What to do if employee has badge showing 150 mrem exposure for a month? nothing. This is within projected limits of 5 rem/year
What to do if employee has badge showing 500 mrem exposure for a month? this is projected to put the employee at 6 rem for the year if it continues, which is above the 5 rem/year threshold for reporting to the State. (bad – tell employee and change situation/habits/practices)
scattered + absorbed equals ____. attenuation, pg 115.
Organ weighting factor for gonads (b/t 0 and 1, compared to other organs) 0.25. pg 131.
1 Gy is how many rad? 1 Gy equals 100 rads
For standard imaging procedures, beyond ______ feet, the amount of scattered radiation is roughly at background levels. 6 feet
Since the quality factor QF for x-rays (photons) is 1, therefore the rad and rem are _____. equivalent, when considering the biological risks of x-ray exposure. Also roughly equiv values to Roentgen?
If a fluoroscopic image is not bright enough for diagnostic purposes, will prolonged observation improve perception? No.
Is the size of the cells in tissue exposed known to be an influence of the biological effects of radiation? No
As the kVp is increased and mAs correspondingly decreases, what happens to the patient skin exposure? The patient skin exposure decreases.
The greatest contribution of unnecessary radiation exposure to the patient stems from the x-ray operator's failure to do what? Failure to collimate the x-ray beam to the area of clinical interest.
During fluoroscopy, which of the following is the highest source of scattered radiation? (Tube housing, tabletop, patient, or image intensifier?) The patient
Must each physician's license for the healing arts be posted in areas where x-ray machines are utilized? No
Modulation Transfer Function (MTF) measures what aspect of image quality? Resolution
Is the dose received by an occupational worker for his/her own medical or dental diagnosis defined as an occupational dose according to the California Radiation Control Regulations? No
When a multifocus image intensifier tube is operated in magnification mode, what happens to the voltage applied to the electrostatic lenses? Greater voltage is applied to electrostatic lenses, causing crossover to occur closer to the input phosphor/photocathode, leading to mag at the output phosphor.
What is the major source of secondary radiation in radiography? The patient's body.
What kind of barrier, if any, must be in all walls, floors and cielings exposed to the useful (primary) beam? A "primary barrier" is an appropriate barrier against the "primary beam." This should be the x-ray film/cassette, or the II.
What are two reasons why film badges are used by radiation workers? They are practical means of providing long term exposure records & they can measure the dose to the worker with reasonable accuracy.
What will moving the image intensifier away from the patient do in regards to patient dose in a fluoroscopy system equipped with ABS & the tube is fixed below the table? Moving II away from patient will increase patient dose.
Which of the following are features of fluoroscopic equipment designed to reduce radiation to the patient? ...collimation, protective lead curtain, dead-man switch? collimation & dead-man switch.
If the exposure area is doubled by opening the collimator, what will happen in regards dose amount to patient & exposure to the operator? It will double the patient dose & double the exposure to the operator.
Which of the following is not considered a safety feature of a fluoroscope? grid ratio of 16:1, dead-man switch, bucky slot cover, cumulative timer? A grid ratio of 16:1 is not considered a safety feature of a fluoroscope. (High ratio, if anything increases dose to patient, but grid has nothing to do with safety really.)
If the collimating cone/diaphragm of mobile fluroscope unit is removed while the unit is in operation, which of the following will occur..... An audible signal, red light glowing on control panel, production of x-rays prevented by interlock, nothing? The production of x-ray's will be prevented by an interlock if the collimating cone/diaphragm is removed while the unit is in operation.
If I am fluoroing a patient using 80 kVp, what should the intensity of the x-ray beam at the tabletop not exceed how many rad/minute for each mA of current? (...0.2, 1.0, 2.2, 5.0?) Tabletop dose of 2.2 rads/minute per mA of current should not be exceeded at 80 kVp.
The central portion of the output phosphor of the image intensifier possesses the greatest ____. (distortion, aberration, magnification, resolution?) greatest resolution is at the center
When using fluoroscopy, which of the following is directly proportional to the exposure delivered to the patient? (...kVp, mA, filter thickness, target to panel/tabletop distance?) mA (milliampere)
The dose rate at the tabletop during regular fluoroscopy cannot exceed how many rads/min? May not exceed 5 rads/minute. (regular mode, no AEC, no boost)
Is an automatic brightness control circuit required on a mobile fluoroscopic unit? No.
Is a device to to prevent operation at source to skin distance less then 12" required on a mobile fluoroscopic unit? Yes
Is a device to prevent operation when the x-ray beam is not intercepted by the primary beam required on a fluoroscopic unit? Yes
During a 2 minute (fluoro exposure time) routine UGI series, a typical x-ray exposure to the patient is how many Roentgens? 5.0 Roentgens
In what unit does the film badge report express an individual's radiation dose equivalent? rem
How long does the California Radiation Control regulations require that individual radiation monitoring records be preserved by the employer after termination of employment of a technologist or technician? indefinitely
What does Flux Gain define? Ratio of how many light photons are produced by each electron at the output phosphor, to the photons liberated by the x-rays interacting at the input phosphor.
Does light in the fluorscopy room influence the tabletop exposure rate? Does filtration? Does kVp? Does target to panel distance? No. Yes. Yes. Yes.
A protective curtain should be interposed between the operator & the patient because scattered radiation exposure at 1 foot from the patient can be as high as how many mrad/hour? 500 mrad/hour
What type of exposure switch is the one that stops when the pressure on it is released? Must a fluoroscopy machine this type of switch? A dead-man switch. Yes.
How many mm lead equivalent is required for protective aprons used during fluoroscopy according to California Radiation Control Regulations? 0.25 mm lead equivalent
Which of the following would cause greatest skin dose to the patient? (...short SID, long SID, Small Focal Spot, Highest practical kVp?) Short SID would cause the greatest skin dose to the patient.
What is the normal viewing distance for an image? 12"-15"
If the x-ray tube is moved rapidly during a fluroscopic exam, the image will blur. Which of the following is this a result of.... too low kVp, too low mA, camera tube lag, quantum mottle? Camera tube lag
What is the function of an Automatic Brightness Control Mechanism of an image intensified fluoroscope? To maintain a fixed dose rate to the image intensifier
What does the equation (normal mode size) squared/(magnification mode size)squared represent? Increase in patient dose in magnification mode
What is the correct position to wear a film badge during fluoroscopy? Above the apron at the collar level
If 1 rad = 100 ergs/gram, what is the dose if 3 grams of tissue absorbs 300 ergs of x-ray? 1 rad = 300 erg / 3 grams = 100 erg/gm
Is a continuous audible signal required during boost mode fluroscopy? Yes
Is continuous manual activation required for boost mode fluroscopy? Yes
Is the tube current and potential increased above normal limits in boost mode? Yes
Which of the following film sizes utilized by the spot filming camera result in the greatest dose to the patient..... 35mm, 70mm, 90 mm, 105mm? 105 mm
What is the technique called that's used to prevent the flicker effect during the viewing of the TV image? Interlaced scanning
Which of the following methods of gonadal shielding is best for use during fluoroscopy..... shaped contact shielding, shadow shielding, flat contact shielding? Shaped, contract shielding.
The source to skin distance for image intensification should not be less than how many inches of the following...... 5", 15", 18", 40"? Should not be less than 18"
What is a typical setting for mA of the following for spot filming..... 2, 5, 10, 150? 150 mA
California State Fluroscopy Syllabus requires that kVp (tube potential) and mA (current)be monitored how often? Daily
For mobile C-arm fluoroscopic equipment, inherent provisions must ensure a minimum source source to skin distance of how many inches? 12 inches
The California Radiation Control regulations require that the minimum lead equivalence of gonadal shielding must be what? 0.5 mm lead equivalent
What is Vignetting? A decrease in light intensity at the periphery of an image.
What is the maximum exposure a pregnant occupational worker may receive during a 9 month gestational period? 500 mrem
What units are used to measure resolving power? line pairs/mm
Which of the following characteristic describe contrast media.... Solid form, high atomic number, low atomic number, low toxicity? High atomic number and low toxicity
Which of the following are disadvantages of using a flat piece of lead for gonadal shielding..... Cannot be used for erect views, difficult to keep in place, is not very useful for fluoroscopy? All of them
What is the purpose of synchronization in CINE? To operate the camera shutters at the same frequency as x-ray pulses and thus decrease patient dose.
The recognition of integration time of the human eye is the time it takes for recognition of an image. How long is this time? 0.2 seconds
During fluoroscopy, which of the following is an acceptable position for the technologist to stand? (...In the room next to the patient? in the room next to the radiologist? in the room as far from the patient as practical? holding the patient?) In the room as far from the patient as practical.
Which of the following factors result in a brighter image being produced at the output phosphor of an II? (type of camera, tungsten filament (cathode), flux gain, minification gain?) Flux Gain & Minification gain are factors that result in a brighter image being produced at the output phosphor.
Which of the follwing is the best description of a virtual image? (image created by actual intersection of light rays, image on cine film, image seen on the monitor, image that cannot be seen an exists only for computational purposes?) The image seen on the monitor
When switching from a 15" to 19" TV screen does the number of horizontal lines change? No
Which of the following describes a closed circuit TV system..... broadcast through air waves, has all its signals carried through cables, has all its circuits on one line, produces no signal at all? A closed circuit TV system has all its signals carried through cables.
The rods of the eye are principally used for what type of vision? Dim light vision, or scotopic vision.
When does electronic intensification occur in the II? When the electrons are moved at high speed from the photocathode to the output phosphor.
A technologist will receive most of the occupational exposure from which types of the following radiation? (Primary, Scattered, Exit, Gamma?) A technologist will receive most of their occupational exposure from SCATTERED radiation.
California Radiation Control Regulations require the total filtration permanently fixed in the useful beam for fluoroscopy may not be less than what Al equivalent? May not be less that 2.5 mm Al equivalent.
The intensity of the x-ray beam at the tabletop during fluroscopy should not exceed how many Roentgen's/minute for each mA of operating tube current at 80 kVp? 2.2 Roentgen/minute
The mA setting for fluroscopy is typically less than what? 5 mA
What is the predetermined time limit that must not be exceeded for the cumulative manual reset timer? 5 minutes
Fluoro equipment manufactured after 8/1/74 equipped with AEC shall not operate at any combo of kVp and mA which will result in an exposure rate at the point where the center of the useful x-ray beam enters the patient in excess of ____. 10 rad/minute. pg 40, bottom paragraph
Fluoro equipment manufactured after 8/1/74 WITHOUT AEC and not using boost mode shall not operate at any combo of kVp and mA which will result in an exposure rate at the point where the center of the useful x-ray beam enters the patient in excess of ____. 5 rad/minute. pg 41, top paragraph
Which of the following will terminate fluroscopy after a preset period of time? (...phototimer, cumulative timer, cumulative dose timer, fluorescent timer?) cumulative timer
Genetic dose refers to what? The effects exhibited in future offspring of persons who have been irradiated.
What is the most conservative type of dose effect curve and also the curve upon which radiation protection guides and regulatory requirements are based is what? Linear Non-Threshold
Radiosensitivity of tissues depends on which of the following..... degree of mitotic activity, number of undifferentiated cells, length of time cells of tissue are in active proliferation, size of cells? The degree of mitotic activity, number of undifferentiated cells, length of time cells of tissue are in active proliferation (NOT size of cells)
How many rads of acute x-radiation in diagnostic energy range to the eyes will result in the formation of cataracts? Several hundred rads
Which of the following is a disadvantage of a thermoluminescent dosimeter (TLD)? (...Recharging is necessary, range of measurement is limited, not reusable, no permanent record is provided?) No permanent record is provided since dose is cancelled when TLD is read
X-ray photons during fluoro are primarily absorbed by which of the following? (...primary barrier, the patient, air, image intensifier?) The patient
Source to tabletop distance in fluoroscopy shall not be less than how many inches? 12 inches
Which of the following may perform fluoro if they possess a valid up to date certificate issued by the State? (...certified RT, limited permit technician, student of RT, licentiate of the healing arts (physician)?) a certified RT and a physician
When misdirected light photons reach the output phosphor, image density increases or decreases & image contrast increases or decreases? When misdirected light photons reach the output phosphor, image density INCREASES & image contrast DECREASES.
Why does the lag or blurring occur when utilizing a vidicon camera? It takes a certain amount of time for the image to build up and decay on the vidicon target.
What is the minimum lead equivalent that the opening for the bucky tray must be covered by? 0.25 mm lead equivalent
What term is a recommendation that is required to meet accepted standards? Shall
What term is a recommendation that is to be applied when practical? Should
Which of the following do not effect patient exposure... 3 phase generators, collimation, target to panel distance, exposure time? 3 phase generators
A high radiation area is any area accessible by individuals in which there exists any radiation an individual could receive in any 1 hour a dose to the whole body in excess of how many rem? 0.1 rem
A radiation area is any area accessible to personnel in which there exists radiation at such levels that a major portion of the body could receive in any 1 hour a dose in excess of how many rem? 0.005 rem
A controlled area is what? An area in which radiation safety rules are enforced.
Which of the following is record keeping not required for? (...results for each calibration survey & test, each reciept transfer & disposal of an x-ray machine, each RT who is hired by the hospital, radiation exposure monitoring of required individuals?) "Each RT who is hired by the hospital" is not required by the California Radiation Control Regulations record keeping.
The rad is a unit of what? Absorbed dose
The preferred fluoro technique utilizes what in regards to kVp & mA? high kVp, low mAs
the rem is a unit if what? radiation equivalent man, absorbed dose equivalent
The SI unit analogous to the rad is what? The Gray
The SI unit analagous to the rem is what? The Seivert
When electrons strike the target of an x-ray tube most of the energy is converted to what? Heat
The HVL is what? The thickness of a specified substance which reduces the intensity of the primary beam by one half
What is Vignetting? A decrease in brightness at the periphery of an image intensifier.
What is the approximate exposure in rads a patient would receive during 5 minutes of fluoroscopy? 10-30 rads
A protective drape, or sliding panel of a minimum thickness of what lead equivalent should be positioned between fluoroscopist and patient to absorb scattered radiation? 0.25 mm of lead
Should film badges be worn under the lead apron at gonadal level? No
If an occupational worker receives an exposure of 5 rems to the skin of the whole body must the State of California be notified? No
Which of the following types of cells is most sensitive to the effects of radiation? (...Muscle, brain, red bone marrow, skin?) red bone marrow
Which of the following has been called an occupational disease of radiologists? (...liver cancer, leukemia, tuberculosis, lymphoma?) Leukemia
Visual acuity is the ability to do what? To perceive fine detail
What is the grainy appearance in an image caused by statistical fluctuation of absorbed x-ray photons? Quantum mottle
What is the brightness ratio between two adjacent areas of a fluroscopy image? Image contrast
Automatic Brightness/Exposure Stabilization/Control is designed to compensate for changes in what? tissue density
Fluoroscopy normally utilizes a tube current in what mA range? 1-5 mA
If a protective apron of 0.25 mm of lead is worn, what is the typical exposure reduction? 0.97 (or 97%)
Which of the following is the best protective eyewear for the operator to utilize during fluoroscopy? (...polaroid glasses, lead glass contact lenses, eyeglasses, lead glass protective goggles and glasses?) Lead glass protective goggles and glasses.
What is the highest source of unnecessary radiation exposure to the patient? Improper collimation
Which of the following are true about fluoroscopic imaging? (...increasing kVp increases contrast, increasing mA reduces patient dose, reducing kVp increases patient dose, reducing mA increases contrast?) reducing kVp increases patient dose
A strong correlation exists between the incidence of leukemia and the mean radiation dose received by which of the following? (...gonads, thyroid, bone marrow, skin?) bone marrow
Stray radiation coming from the x-ray tube housing is called what? leakage radiation
Which of the following is not a personnel monitoring device? (...Geiger counter, pocket chamber or dosimeter, TLD, film badge?) Geiger counter
The most common material used in TLD is which of the following? (...Calcium Fluoride, Potassium Fluoridentrous Oxide, Lithium Fluoride, Nitrous Oxide?) Lithium Fluoride
The input phosphor of the modern image intensifier is made of which of the following? (...Zinc Cadmium Sulfide, Sodium Iodide, Cesium Iodide, Calcium Tungstate?) Cesium Iodide
What are the 3 basic principles which may be used singly, or in combination, to reduce exposure to x-rays? Time, Distance, Shielding
Utilizing the inverse square law, if distance is doubled from source of radiation, the exposure will be reduced to what fraction of the original dose? 1/4
Diagnostic type tube housing means that when tube is operated, leakage radiation at a distance of 1 meter from the target cannot exceed how many mrad? 100 mrad
For both fluoroscopic and radiographic mobile equipment, provisions must be made so that equipment may not be operated at less than what source to skin distance? May not be operated at less than 12" (30cm) source to skin distance
The resolution of the modern input phosphor of an II in non-magnification mode is what lp/mm? 4 line pair/mm
The output phosphor of most modern II is made of which of the following? (...Zinc Cadmium Sulfide, Cesium Iodide, Sodium Iodide, Calcium Tungstate?) Zinc Cadmium Sulfide
To keep the light output of the II constant, ABS compromises between which of the following? (...patient dose & image quality, contrast & resolution, vignetting & pincushion distortion, mag mode & non mag mode?) patient dose & image quality
Which following component of the II tube is responsible for focusing the electron field? (...input phosphor, photocathode, electrostatic lenses, glass envelope?) electrostatic lenses
The overall ability of an II to increase image illumination is called what? Brightness Gain
The ratio between a TV monitor's vertical resolution & total number of scan lines is called what? Kell factor
What is the number of horizontal lines on a standard fluoro TV monitor? 525
Which of the following is the ultimate limitation of image quality from an II? (...vignetting, tube lag, pincushion distortion, the number of x-ray photons absorbed by the system?) The number of x-ray photons absorbed by the system
Which of the following recording systems has the poorest resolution? (...CONE, VHS, Spot Filming, Videodisc Recording?) VHS recording system has the poorest resolution
High film badge readings are presumed to be caused by which of the following? (...Improper storage of film badge, Inaccurate processing when film is read by badge company, Heat exposure, Poor radiation practices by worker?) Poor radiation practices by the occupational worker.
Organ dose weighting factors? Gonads .25 (the one to remember). Others are breast .15, red marrow .12, lung .12, thyroid .03, bone surfaces .03, remainder .30 (made up of .06 each from 5 "remainder" organs), to equal total of 1.
National Council on Radiat'n Protection and Measurements (NCRP) in report Medical Exposure of Pregnant and Potentially Pregnant Women states risk to embryo/fetus is considered negligible at ____ rad or less when compared to the other risks of pregnancy. 5 rad
Rule of 2s and tens? (orders of magnitude for background vs different procedural radiation doses -- this is not in the syllabus but may be a useful tool) Background .2 rad/yr, CXR .02 rad, AXR .2 rad, CT 2 rads, fluoro 2 rads/min, cine 20 rads/min
Which radiography QC are daily? most automatic processor QC (especially densitometry/sensitometry, thermometer, tank levels, devlpr/fixer replen rate, develpr/wash temp, fixer, water filters, standby unit)
Which radiography QC are monthly? film/chemical storage, darkroom conditions (temp/hum/clean), builtin devlpr thermom accuracy
Which radiography QC are quarterly? retake analysis, silver recovery efficiency, water flow meter accuracy
Which radiography QC are semiannual? darkroom fog, fixer flow meter accuracy, fixer retention, light/xray field alignment, screen-film contact
Which radiography QC are annual? everything else (and anything involving a physicist)
Created by: dudall on 2012-07-01



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