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Fluoroscopy permit

QuestionAnswer
The principal purpose of image intensified fluoro compared to conventional radiography is that it allows for A) higher resolution B)lower patient dose C) real time viewing D) all of the above C
The time it takes for the human eye to adjust to the low light levels of conventional fluro is called Adaptation Time
The operating potential of most modern image intensifier tubes is approximately: 25 kV (pg. 17 - the potential maintained by the accelerating anode in the image intensifier)
The squared ratio of the input to output screen diameter in an image intensifier tube is termed: Minification ratio
When changing from a 9" input phosphor to a 6", you must increase your exposure factor by ___ times. 2.25 (9^2)/(6^2)
The normal mA used for image intensified fluoro is about: A. 1-5 mA B. 6-10 mA C. 25-100 mA D. 100-600 mA A
A standardized method of evaluating the light emission of an image intensifier is called: A) brightness gain B) relative aperture C) signal to noise ratio D) conversion factor D - conversion factor is used in the periodic check of brightness gain, since BG can deteriorate as much as 10% yearly due to the "aging" of the input and output screen phosphors. It's calculated as the [intensity of output phosphor] / input exposure rate
The brightness gain (image brightness) of an image intensifier can be increased by increasing the: A) exposure rate to the input screen B) minification ratio C) acceleration potential of the tube (kVp) D) all of the above D
The principle advantage of the smaller field of the dual field image intensifier is: A)improved image quality B) less minification gain C) lower patient dose D) all of the above A - there is MORE minification gain, and HIGHER patient dose with automatic brightness control to compensate for the decreased brightness
The part of the eyes that detect small object details are: A) phototopic (cone) vision B) scotopic (rod) vision A
During an image intensified fluoro study (manual mode), an increase in kilovoltage will A) lower penetration B) increase pt's dose C)improve image contrast D) decrease pt skin dose D
The increase in light production by an image intensifier resulting from the acceleration of the electrons across the tube is called: A)conversion gain B)minification gain C)electronic intensification D)Lambert gain C - conversion gain isn't a thing (conversion factor is), minification gain is the intensification from the same amount of electrons from the large input screen being squeezed onto the smaller output screen.
The brightness of an image intensified fluoro image is about ____ greater than a conventional fluoro screen image: A) 5-20 times B) 20-40 times C)50-200 times D) 5,000-20,000 times A
If a fluoro tube output is 300 mR at 2 mA, what would the output be at 3 mA? A) 100 mR B) 300 mR C) 450 mR D) 900 mR C - Output, or brightness, varies directly with the change in mA and roughly the square of the kVp.
The reduction of brightness at the periphery of an image intensifier is called: A) vignetting B) diminution C) lateral dispersion D) modulation transfer A
The reduction of field size in a dual field image intensifier is accomplished by: A) increasing the size of the input screen B) increasing electrostatic lens voltage C) decreasing size of the output screen D) decreasing the flux gain B
The point in the image intensifier where the electrons crossover is termed the: A)optical focal spot B) input focal spot C) electronic focal spot D) flux focal spot C
The greater brightness by an image intensifier is in large part due to the incr of electron energy which results from: A) high potential diff across the tube B) photo multiplier to increase signal strength C) grid-controlled x-ray tube D) all of the above A
If an image intensifier has an input screen that is 20 cm, and output screen that is 2 cm, the minification ratio would be… 100 times - (20)^2 / (2)^2
A dual field image intensifier tube with an auto brightness control is being used in the smaller mode. This will result in A) more magnification B) more contrast C ) less image noise D) all of the above D
The output screen is made of zinc cadmium sulfide. This substance serves to convert: A) x-rays into light B) electrons into x-rays C) electrons into light D) light into electrons C
A thin deposit of silver that coats the inside of the image intensifier and, when activated, serves to focus the electron stream is called… electrostatic lens
As magnification of an image increases, the: A) resolution increases B) contrast increases C) minification ratio decreases D) all of the above D
In order to accommodate human eye integration time, each frame of a television image must be presented in less than: A) .5 sec B) .1 sec C) .2 sec D) .9 sec C
If someone receives 100 mR at 1 foot from the fluoro table, what is the dose at 3 ft from the table? 11.1 mR - at 3x the distance, the amount of exposure is 1/(3^2)
Normal viewing distance for binocular vision 10-14 inches
A person standing 2 ft from the table for 15 min receives a dose of 50 mR. What is the dose if they were 4 ft away for 12 min. 10 mR - 50 mR/15 min * 1/(2^2) * 12 min
A certain x-ray tube, at some given kVp, delivers 100 mR at 3 feet distance. At 1 foot, the output in mR would measure… 900 mR - using the inverse square rule again
The part of the image intensifier that converts light to electrons is the… Photocathode
The diameter of the input phosphor to the diameter of the output phosphor is the formula for A) minification gain B) brightness gain C) flux gain Minification gain
Of the following imaging modalities, which has the best RESOLUTION? A) TV monitor B) cine film C) spot film radiograph D) video disc C
The operators radiation dose is proportional to: A) mA used B) patient's dose C) kVp used D) size of the field Patient's dose
The kVp is commonly referred to as the A) intensity B) quantity C) quality D) velocity quality
Ratio between the vertical resolution and horizontal resolution is calculated using… Kell Factor
The intensity measured at the table top at 80 kVp should not exceed ____ for each mA of operating current. A) 1.5 R/min B) 2.2 R/min C) 5 R/min D) 10 R/min B
The max exposure rate (where the useful beam enters pt) for fluoro equipment WITH automatic exposure rate controls 10 R/min
The max exposure rate (where the useful beam enters pt) for fluoro equipment WITHOUT automatic exposure rate controls 5 R/min
The Target-to-Panel Distance that is optimal is ___ inches, and may be no less than __ inches. optimum 18 inches, no less than 12 inches.
Increasing Target-to-Panel Distance [increases/decreases] the patient dose. decreases dose, due to loss of low energy X-rays and energy intensity as per the inverse square law.
The reason for personnel monitoring is to document that no one receives more than: A) 1/10 MPD B) MPD equivalent C) 1.25 per quarter D) 5000 mR B- MPD= Max Permissible Dose
Proper dark adaptation takes approx: A) 15 min B) 30 min C) 45 min D) 60 min 30 min
The maximum allowable tabletop dose rate with High Level (Boost) Fluoroscopy when acquiring images without recording 20 Rads/min
All are true about Boost Fluoro EXCEPT: A) increases patient dose above normal limits; B) continuous manual activation required; C) continuous audible signal required; D) all of the above D
Max Permissible Doses, per year, for: (1) Whole body [total effective dose equiv] (2) Lens of the eye [eye dose equiv] (3) Skin and extremities [shallow-dose equiv] (1) 5 rem, (2) 15 rem, (3) 50 rem
Radiation dose limits for members of the public (per year, and in any one hour) 0.1 rems/year, 0.002 rems (2 millirem) in any one hour
SI unit for absorbed dose Gray - 1 joule/kg
Special unit for absorbed dose Rad - corresponds to absorption of 100 ergs/gram
SI unit for dose equivalent Sievert
Special unit for dose equivalent Rem - unit devised to allow for the fact that the same absorbed dose in rads delivered by different kinds of radiation do not produce the same degree of biological effect.
What is the total dose received if the exposure rate is 25 mR/hr and you're exposed for 6 minutes? 2.5 mR
Which of the following will decrease patient exposure without decreasing brightness? A) increase target-to-panel distance B) increase kVp C) Decreasing the field size D) Increase distance from intensifier to the patient C
The aluminum equivalence of the table top may not exceed ___ mm at 100 kVp 1.0
The shaped contact gonadal shield used during fluoro must contain at least ___ mm lead equivalent 0.5
An area controlled by state regulation where radiation safety is used and enforced is called a: A) high radiation area B) controlled area C) skin D) gonads B - Controlled ARea
When the fluoroscopic x-ray is located above the table, the exposure rate is measured: A) 1 cm above the table with a 9" phantom; B) 30 cm above the table with a 9" or 7.9" phantom; C) 18" above the table with a 7.0" phantom B
Resolution is measured using a: A) line pair grid B) wire mesh tool C) star pattern D) wisconsin test cassette A - line pair grid
Which of the following serves as the PRIMARY BARRIER for a fluoro x-ray tube? A) leaded walls B) image intensifier C) patient D) tabletop B - image intensifier
Doubling your distance from a source of radiation results in a reduction of your dose to ___ of the original dose… 1/4
The best position for filming the Gallbladder is the upright: A) RPO, suspended resp. B) RPO, inspiration C) RPO, expiration, compression D) LPO, insp, comp C
Which of the following will most often obscure the GB? A) splenic flexure B) small bowel C) colonic gas D) stomach C - colonic gas
Both the bucky slot cover and the protective curtain of a fluoro unit must have a minimum lead equivalent of ___ mm. 0.25 mm
Function of an auto brightness control mechanism is to: A) maintain a fixed dose rate to the PATIENT, B) maintain fixed dose rate to the IMAGE INTENSIFIER, C) limit exposure time, D) prevent excess x-ray tube heating B
During a CINE exam with 35 mm film and frame rate of 30 frames/sec, what is the exposure rate to the skin? A)1000-5000 mR/min B)5000-10,000 mR/min C)10-20 R/min D)50-100 R/min A - 1-5 R/min
A fluoroscope using 2.8 mA emits 1.4 R/mA/min. What is the total exposure if 5 minutes of fluoro is used? 19.6R
At 1 ft from radiation source the exposure is 240 mR/hr. What would be your exposure if you moved 2 ft from source for 15 min? 15 mR
As the kVp is increased, and the mA's correspondingly decrease… A) image contrast increases B) image distortion increases C) patient skin exposure increases D) patient skin exposure decreases D - higher kVp is higher "quality" and will pass through the skin better
Greatest contribution of unnecessary radiation exposure to the patient comes from failure to: A) collimate x-ray beam to area of interest B) use proper gonadal shielding C) use fast screens and film D) use proper exposure factors A
You can reduce patients fluoro dose by A) moving the source further away B) moving the source closer C) decreasing kVp A
For a fluoro system with Auto Brightness Control, with x-ray tube fixed below the table, moving the image intensifier away from the pt will: A) reduce image size B) increase size of radiation field C) decrease patient dose D) increase patient dose D
Which is NOT required on mobile fluoro (C-arm)? A) image intensifier B) device to prevent operation when X-ray beam is not intercepted by the primary barrier C) automatic brightness control D) device to prevent operation at source-to-skin distance <12 in. C
Quantum mottle decreases the visible detectability of: A) low contrast objects B) high contrast objects C) spacial resolution D) subject contrast B
All of the following directly influence the table top exposure rate EXCEPT: A) filtration B) target-to-panel distance C) kVp used D) light in the fluoro room D
If 2 grams of tissue absorbs 200 ergs of x-ray, what is the exposure dose? 1 Rad
When a C-arm is used for chest x-ray, in which direction is there the most scatter, in relation to the primary beam? A) 45 deg B) 90 deg C) 135 deg D) 180 deg A
The typical mA setting when taking a spot film 150 mA
Which of the following is NOT regulated by state provisions for quality control checks: A) exposure rates B) kVp accuracy C) mA D) filtration D
What is the purpose of synchronization in Cine? To operate the camera shutter at the same frequency as X-ray pulses, thus decreasing patient dose
What is the integration time of the human eye (how long it takes for formation of an image)? 0.2 sec
All x-ray tubes must have diagnostic type tube housing, meaning the leakage radiation at 1 meter distance may not exceed ___mR/hr. A) 10 B) 25 C) 50 D) 100 100 mR/hr
What is the exposure reduction with an apron of 0.25 mm lead equivalent? A) 90% B) 95% C) 97.5% D) 99% 97.5%
State regulation requires all fluoro tubes to contain a minimum of ___mm Aluminum filtration. 2.5 mm aluminum equivalent
The aluminum equivalence of the table top may not exceed ___ mm at 100 kVp 1.0 mm
When filming in cineangiography, the max magnification is achieved with: A) max horizontal framing B) total overframing C) exact framing D) high resolution framing B - total overframing
Tabletop exposure rates must be measured by a physicist at least A) monthly B) yearly C) every 3 yrs D) every 5 yrs yearly
The image intensifier turns x-rays into ___, then into ___, then into ___ X-rays into light, then into electrons, then into light.
The output phosphor is composed of… zinc cadmium sulfate
The most conservative type of dose-effect curve, and the curve upon which radiation protection guides and regulations are based is the: A) linear non-threshold curve, B) linear threshold, C) non-linear non-threshold, D) non-linear threshold. A
If only one personnel monitoring device is worn, it must be located where? Outside lead, collar level
The main source of exposure for the fluoro operator comes from scattered radiation coming primarily from where? the patient
What is the approximate exposure a pt would receive during 5 min of fluoroscopy? 10-30 roentgens (2-6 R/min?)
If a pregnant patient received total skin exposure of 5 rads, what is approx dose to the fetus? 100 milliards (1/50th of entrance dose)
Regulations state that tube potential (kVp) and current (mA) shall be monitored how frequently? Daily (p. 105)
The max exposure a pregnant technologist may receive during her entire gestational period is: (A)100 mrem (B)250 mrem (C)500 mrem (D)5000 mrem 500 mrem
Max exposure a pregnant technologist may receive PER MONTH .05 rem or 50 mrem
Max exposure a pregnant technologist may receive for the rest of her pregnancy if she has already received 500 mrem exposure .05 rem or 50 mrem
A "high radiation" area is where you could receive in any one hour a whole body dose in excess of: (A)5 mrem/hr (B)50 mrem/hr (C)10 mrem/hr (D)100 mrem/hr 100 mrem/hr
During a 2 min routine Upper GI series, a typical x-ray exposure to the patient is: (A)0.5-1.0 R (B)1-3 R (C)6-10 R (D)30-50 R 6-10 R (3-5 R/min?)
Created by: 1300043