Help
Options
Question
__________Provide constant OD regardless of tissue thickness, composition and exposure time.
ABC
Back up timer
Auto transformer
click to flip
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't know
Question
mR/mAs value must be within ___________________% between adjacent mA stations.
5%
10%
15%
20%
5%
10%
15%
20%
Remaining cards (203)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
MOCK EXAM
VARKEY FINAL
| Question | Answer |
|---|---|
| __________Provide constant OD regardless of tissue thickness, composition and exposure time. ABC Back up timer Auto transformer | AEC |
| mR/mAs value must be within ___________________% between adjacent mA stations. 5% 10% 15% 20% | 10% |
| Incomplete erasure of a previous image on a CR Imaging plate might cause __________ | Ghost image |
| Failure of electronic preprocessing can cause uninterpretable images due to the presence of _________on the image matrix | Dead Pixels |
| Which of the following artifact occurs when the grid lines are parallel to the laser lines in a computed radiography? | Moire |
| A mathematical process of assigning a digital value to a dead pixel based on recorded values of adjacent pixels is known as ________ | Interpolation |
| The effect of irregular pattern (variations in image brightness) can be minimized by: | Flat fielding |
| A software correction that is performed to equalize the response of each pixel to a uniform x-ray beam is known as___________ | Flat fielding |
| If the x-ray exposure field is not properly collimated, sized, and positioned, ___________errors may occur. | Exposure field recognition |
| The artifact shown on the figure provided is caused by: | Back scatter |
| The artifact shown on the figure provided is caused by: | Moire |
| Incorrectly oriented grid, with the grid lines parallel to the plate reader's scan lines will cause: | Moire |
| Electronic memory artifacts are cause by: | Too rapid exposure |
| The test pattern shown in this image is used for: | Evaluation of contrast resolution |
| If the viewer sees the reflection only at one point it is known as: | Specular Reflection |
| A mammographic examination performed on asymptomatic patient is known as: | Screening mammography |
| Thick dense breasts are imaged better with ______________ target filter combination. | Rh/Rh |
| A very small effective focal spot size of 0.3/0.1 is obtained by: | Angling the anode 23 degree Tilting the x-ray tube 6 degree. |
| What technique can be used to ensure that the breast tissue next to the chest wall is included in a mammographic image? | Tilting the x ray tube 6˚ |
| Why a compression technique is used in mammography? | Tissues nearer the chest wall are less likely to be underexposed. Tissues nearer the nipples are less likely to be overexposed. Reduced focal spot blur |
| The electronic noise in digital mammography can be reduced by ________________ . | Cooling the detector |
| Which of the following has the best spatial resolution? Digital mammogram Screen film mammogram CR mammogram | Screen film mammogram |
| A repeat rate of _________% is acceptable. | 2% |
| To get an accurate result from a repeat rate analysis, at least _________mammograms should be included in the analysis. | 250 |
| Which of the following trajectory will provide maximum blurring of the unwanted structures on a tomographic image? Elliptical Circular Spiral Linear | Spiral |
| The ___________ is a pivot point along the connecting rod between the x-ray tube and the film in a tomographic system. | Fulcrum |
| The larger the tomographic angle, the _____________ the tomographic layer is: | Thiner |
| If a radiograph of the femur measures 24cm and the magnification factor is 2, what is the actual size of the femur? | MF=Image Size/Object Size 12 |
| A radiograph of the chest is taken with patient positioned at a distance of 72 inches from the IR. The heart of the patient is approximately 4 inches from the image receptor. If the image of the heart measures 36 cm, what is the magnification factor? | MF=SID/SOD SOD=SID-OID. SOD=72-4. SOD=68 MF=72/68. MF=1.06 |
| What is the formula for the magnification factor using image and object size? | MF=Image Size/ Object Size |
| Molybdenum produces characteristic x-rays with energy of _______________ keV | 19 |
| The output phosphor of the image intensifier is composed of _____. | Zinc cadmium sulfide |
| The output phosphor of the image intensifier converts _____ to _____. | Electrons, light |
| The photocathode of the image intensifier convert _________ to _____________ | Light, electrons |
| Scattered radiation in the form of x-rays, electrons, and particularly light can reduce the contrast of image intensifier tubes through a process called: ________________ | Veiling glare |
| _____________________ is the reduction in brightness at the periphery of the image. | Vignetting |
| X-rays that exit the patient and enter the image intensifier first interact with the _____. | input phosphor |
| The input phosphor of the image intensifier is composed of _____. | cesium iodide |
| The input phosphor converts _____ to _____. | X-rays, light |
| The _____ in the image intensifier emits electrons when it is stimulated by light photons. | photocathode |
| The _____ in the retina are stimulated by _____ light | rods, low |
| Which of the following fluoroscopic mode will cause the highest patient dose? 25cm mode 17 cm mode 12cm mode | 12 cm mode |
| Which of the following is the photoconductive layer? Window Signal plate Target plate | Target plate |
| Which of the following material is used as a photoconductive layer? | Antimony trisulfide |
| In a 25cm/17cm/12cm image intensifier which mode will display maximum anatomy? | 25 cm |
| Which of the following fluoroscopic mode will demonstrate the highest spatial resolution? 25cm mode 17 cm mode 12cm mode | 12cm mode |
| In DF spatial resolution is limited by_________ | Pixel Size |
| Calculate the flux gain of an image intensifier that is equipped with a 25cm input phosphor and 5cm output phosphor. 5 25 125 None of the above | Flux gain = number of output light photons/ number of input x-ray photons None of the above |
| An image intensifier has a 12cm input phosphor and 4cm output phosphor. Approximately 50,000 light photons were produced at the output phosphor when the input phosphor received 100 x-ray photons from the patient. Calculate the total brightness gain. | Brightness gain= minification gain X flux gain Minification Gain= D1 squared/D2 squared D1 = Diameter of the input phosphor D2 = Diameter of the output phosphor Flux gain = number of output light photons/ number of input x-ray photons |
| An image intensifier has a 12cm input phosphor and 4cm output phosphor. Approximately 50,000 light photons were produced at the output phosphor when the input phosphor received 100 x-ray photons from the Pt. Calculate the total brightness gain. (Cont) | Mini Gain= (12/4)squared Mini Gain=9 Flux Gain= 50000/100 Flux Gain=500 Brightness G= 9x500 Brightness G= 4500 |
| In digital fluoroscopy, the spatial resolution is limited by: | Pixel size |
| The ___________ is the preferred site for an arterial puncture, because of its size and easily accessible location. | Femoral Artery |
| Guide wires are usually coated with a __________material so the catheter slides over the wire more easily. | Hydrophilic material |
| The ________ guide wire is designed for use in atherosclerotic vessels filled with plaque. | J.Tip |
| Catheter diameter is categorized in____________ | Fr |
| A left cerebral angiogram is performed with a 0.3-mm focal spot at 72 cm SID. The artery to be imaged is 10 cm from the image receptor. What is the the focal-spot blur? | FSB = Focal spot size (OID/SOD) FSB=0.3mm(10cm/62cm) FSB=0.048mm |
| What is thrombolysis? | Injecting drugs to dissolve dangerous clots in blood vessels |
| Viewing the fluoroscopic image in magnification mode increases _____. | Contrast resolution Spatial resolution patient dose |
| A charge-coupled device used in digital fluoroscopy provides high _____. | spatial resolution signal-to-noise ratio detective quantum efficiency |
| About 80% of breast cancer occurs in ________ tissue. | Ductal |
| The inventor of clinical computed tomography: | Hounsfield |
| Which of the following CT generation/s used rotate translate motion of the x-ray tube? First generation Fifth generation Third generation Fourth generation | First generation |
| Most of the CT scanners used today are ___________generation scanners. | Third generation |
| Which of the following lead to the development of helical/spiral scanning? | Slip ring |
| Which of the following Field of Views (FOV) will produce most magnified images? 42 FOV 25 FOV 21 FOV 15 FOV | 15 FOV (the smallest one) |
| A single picture element of the mage matrix is called a ___________ | pixel |
| Which of the following determines image contrast: Window width Window level | Window width |
| Which generation of CT scanner first used a fixed ring of detectors? | Fourth |
| The degree of attenuation values of each voxel is then converted into a numeric scale called: | CT Number |
| Which of the following CT number represent water? 0 +100 -100 +3000 | 0 |
| Air, which produces the least amount of attenuation has the value of: | -1000 |
| Window levels controls: | Image brightness |
| _________is a ratio reflecting the relationship between table speed and slice thickness. | Pitch |
| What is the pitch if the slice thickness selected is 10 cm and the table moves 10 cm during one rotation of the x-ray tube around the patient? | Pitch=length of table travel per rotation/slice thickness Pitch=10/10 Pitch=1 |
| The preliminary image of a CT scanner is called: | Scanogram Scout Topogram |
| Scan FOV can not be bigger than display FOV (reconstruction FOV): | False (Display (reconstruction) FOV has to be equal or smaller than Scan FOV) |
| The component of the CT computer system responsible for the data processing of image reconstruction is the: | array processor |
| The loss of anatomic information between contiguous sections due to inconsistent patient breathing is called: | misregistration |
| Which of the following terms is used to describe a set of rules for solving a mathematical problem? reconstruction algorithm function array | algorithm |
| Which of the following factors does not affect the dimensions of a voxel? slice thickness matrix size kernel display field of view | kernel |
| Which of the following types of gas is commonly used for gas ionization CT detectors? xenon cadmium tungstate helium nitrogen | xenon |
| What is the purpose of fluoroscopy? | To view dynamic anatomy |
| In a stationary fluoroscopic unit, where is the fluoroscopic x-ray tube located? | Under the table |
| What is the normal tube current during fluoroscopy? | 1 to 5 mA |
| What conversion occurs in the image at the input phosphor of an image intensifier tube? | x-ray into visible light |
| What conversion occurs in the image at the photocathode of an image intensifier tube? | light into electrons |
| What is photoemission? | The emission of electrons from the photocathode |
| What conversion occurs in the image at the output phosphor of an image intensifier tube? | Electrons are converted to visible light |
| At what stage of an image intensified fluoroscopy is the number of photons lowest? | Entering the input phosphor |
| Which comes first in image intensified Fluoroscopy? | Cesium Iodide screen (input phosphor) |
| Which comes last in image intensified fluoroscopy? | Zinc Cadmium Sulfide Screen (output phosphor) |
| What is the process called when an image intensifier tube makes a dim image brighter? | Brightness gain |
| Which of the following will affect the total brightness of an image intensification tube? Flux gain Minification gain Primary beam intensity All of the above | All of the above |
| The image intensifier's input phosphor differs from the output phosphor in what way? | Is much larger |
| The brightness level of the fluoroscopic image can vary with which of the following? mA Kvp Patient size All of the above | All of the above |
| Which of the following describes the fluoroscopic system designed to maintain constant image brightness? | Automatic brightness control ( ABC ) |
| Automatic brightness control (ABC) is designed to compensate for changes in which of the following? | Technique selection |
| What happens when a multi-focus image intensifier tube is operated in the magnification mode? | The electron focal point is closer to the input phosphor |
| When using a multi-focus image intensifier tube in the magnification mode | Resolution is improved |
| When using a 25/17/12 image intensifier tube, which of the following is true? Resolution is best in the 25 cm mode There are three different input phosphors Resolution is best in the 17 cm mode The field of view is largest in the 25 cm mode | The field of view is largest in the 25 cm mode |
| How is the electron beam in a television camera tube produced? | Thermionic emission |
| The electron beam in a television camera tube is controlled by which of the following? Steering coils Accelerator grids Control Grid All of the above | Steering coils Accelerator grids Control Grid All of the above |
| The target assembly of a television camera tube consists of which of the following? Window Singnal plate Target All of the above | All of the above |
| Which of the following is photoconductive? Window Signal plate Target plate Electron gun | target plate |
| Which component of the television monitor transfers the video signal into a visible image? | Fluorescent screen |
| Random background interference that is often referred to as "snow" on a television is called what ? | Noise |
| An image intensifier has a 12cm input phosphor and 4cm output phosphor. Approximately 50,000 light photons were produced at the output phosphor when the input phosphor received 100 x-ray photons from the patient. Calculate the total brightness gain. | 4500 |
| Viewing the fluoroscopic image in magnification mode increases _____. Contrast resolution Spatial resolution Patient dose All of the above | All of the above |
| During DF, the under-table x-ray tube actually operates in the ___________ | radiographic mode |
| In DF, the time required for the x-ray tube to be switched off is called ___________ | extinction time |
| In digital fluoroscopy, the fraction of time that the x-ray tube is energized is called: | duty cycle |
| The SNR of digital fluoroscopy is: | 1000:1 |
| The combination of temporal and energy subtraction techniques is called _____. | hybrid subtraction |
| The time it takes to turn on the digital fluoroscopy x-ray tube and reach the selected mA and kVp is the _____ time. | interrogation time |
| ______________ is useful for the placement of catheters and wires in complex and small vasculature. | Roadmapping |
| How magnified is the image of a 36/25/12 image intensifier in the 12cm mode compared with 36 cm mode? | 3 times |
| Which of the following produces a sharper image with fewer flickers? Progressive mode Interlaced mode | Progressive mode |
| A _____ is an example of an exposure artifact. | foreign object |
| A quality assurance program monitors _____. | people |
| A quality control program is for _____. Digital image processors CT scanners x-ray tubes all of the above | all of the above |
| Medical facilities have quality control programs in place in order to _____. have JAHCO approval and accreditation ensure quality patient care receive payment from insurance carriers do all of the above | do all of the above |
| Most quality control testing on radiographic equipment is done _____. | annually |
| All general purpose radiographic units must have a minimum of _____ mm Al filtration. | 2.5 |
| The collimator must be accurately aligned to within ±_____% of the SID. | 2 |
| It is acceptable to perform a(n) _____ test instead of measuring the focal spot size. | line pair |
| The measured kVp should be within ±_____% of the kVp indicated on the console. | 10 |
| Comparing the mR output at 50 mA @ 0.2 sec, 100 mA @ 0.1 sec, and 200 mA @ 0.05 sec is part of a test for _____. | linearity |
| Misalignment must not exceed ____% of SID. | 2 |
| Quality control testing procedures should be performed on _____ basis. a daily and weekly a monthly an annual all of the above | all of the above |
| A positive beam limitation (PBL) device is involved in? | Collimation |
| The three classifications of digital imaging artifacts are _____. | image receptor, software, and object |
| A ghost image can occur in digital imaging because of _____. | incomplete erasure |
| _____ is done during preprocessing to correct for an irregular pattern over the image. | flatfielding |
| The software correction that equalizes the response of each pixel to a uniform exposure of x-rays is called _____. | flatfielding |
| Computer aided diagnoses (CAD) requires the use of _____. | uncompressed images |
| A graph of the frequency of occurrence versus digital value intervals is called a(n) _____. | histogram |
| Creating distinctly collimated margins on all 4 sides of a DR image is important in preventing _____ errors. | histogram analysis |
| A mathematical process of assigning a digital value to a dead pixel based on recorded values of adjacent pixels is known as ________ | interpolation |
| Which of the following artifact occurs when the grid lines are parallel to the laser lines in a computed radiography? Ghosting Quantum mottle Quantum noise Moiré | moire |
| Failure of electronic preprocessing can cause uninterpretable images due to the presence of _________on the image matrix | Dead pixels |
| If the x-ray exposure field is not properly collimated, sized, and positioned, ___________errors may occur. | Exposure field recognition |
| A black line across the digital image is caused by: | Back scatter |
| Extraneous line pattern in a digital image is caused by: | Noise in the plate reader electronics |
| _____________is an artifact that is caused by frequency harmonics | moire |
| Incorrectly oriented grid, with the grid lines parallel to the plate reader's scan lines will cause: | Moire artifact |
| Electronic memory artifacts are cause by: | Too rapid exposures |
| Breast compression has the advantage of lowering. patient dose. motion blur. superimpositions. All of the above. | All of the above |
| Breast compression increases. contrast resolution. spatial resolution. patient dose. Both a and b | Both a and b. |
| Screening mammography requires ___ view(s) of each breast, whereas diagnostic mammography requires _________ views. | two, two or more |
| During tomography the x-ray tube and image receptor move around an imaginary pivot point called the __________. | fulcrum |
| The tomographic angle determines the | slice thickness |
| As the tomographic angle ________ the tomographic section __________________. | increases, becomes thinner |
| Which of the following structures are most blurred in a tomographic image? Structures just above the fulcrum Structures just below the fulcrum Structures farthest from the fulcrum Structures at the level of the fulcrum | Structures farthest from the fulcrum |
| The thickness of the tomographic layer is affected by ___________ of the tube. | tomographic angle |
| If the image size of an object is 3 cm and the magnification factor is 1.5, then what is the actual object size? | 2.0 cm |
| The radiologist has requested that the images for a cerebral angiogram be magnified 100%. Where would you set the SOD of the head if the SID is set at 20 inches? | 10 inches |
| What is the true size of a lesion if its magnified image measures 3 cm and the magnification factor is 1.5? | 2.0 cm |
| It is essential that a ______________________ be used in magnification radiography to preserve image detail. | small focal spot |
| Molybdenum produces characteristic x-rays with energy of _______________ keV | 19 |
| Rhodium produces characteristic x-rays with energy of ___________ keV | 23 |
| Mammography uses an anode angle of _____degree. | 23 |
| Mammography uses a tube tilt of ___________degree | 6 |
| In mammography, the total beam filtration should not be less than ____ mm of Al equivalent. | 0.5mm |
| Which of the following target material is the best for performing mammography of a patient with thick dense breast tissue? | Rhodium |
| Most mammographic system now has a moving grid with a ratio of ________. | 5:1 |
| The electronic noise in digital mammography can be reduced by: | Cooling the detector |
| A minimum of __________ mammograms must be included in a repeat analysis? ` | 250 |
| Tomographic angle and slice thickness are: | Indirectly proportional |
| A panoramic tomogram is used to radiograph the following structures: | mandible |
| Where is the AEC located in a mammography unit? | Underneath the image receptor |
| A magnified radiography of the sella turcica is taken at 100 cm SID with the object positioned 25 cm from the image receptor. If the image of the sella turcica measures 16 mm, what is its actual size? | 12 |
| The accuracy of collimation at a 72-inch SID must be: | ±1.44 inches |
| If the viewer sees the reflection only at one point it is known as: | Specular reflection |
| An SMPTE pattern is used for measurement of: | Resolution of the display system |
| Pincushion and barrel-like distortions can be identified using which of the following test patterns. TG 18 QC TG 18 AD TG 18 CT | TG 18 QC |
| The ___________ is the preferred site for an arterial puncture, because of its size and easily accessible location. | Femoral artery |
| Guide wires are usually coated with a __________material so the catheter slides over the wire more easily. | Hydrophilic material |
| The ________ guide wire is designed for use in atherosclerotic vessels filled with plaque. | J. Tip |
| Catheter diameter is categorized in____________ | Fr |
| What is thrombolysis? | Injecting drugs to dissolve dangerous clots in blood vessels |
| The inventor of clinical computed tomography: ` | Hounsfield |
| Which of the following CT generation/s used rotate translate motion of the x-ray tube? First generation Fifth generation Third generation Fourth generation | First generation |
| Most of the CT scanners used today are ___________generation scanners. | 3rd |
| Which of the following lead to the development of helical/spiral scanning? | slip ring |
| Which of the following Field of Views (FOV) will produce most magnified images? 42 FOV 25 FOV 21 FOV 15 FOV | 15 FOV |
| A single picture element of the mage matrix is called a ___________ | pixel |
| Which of the following determines image contrast: Window width Window level | WW |
| Which generation of CT scanner first used a fixed ring of detectors? | 4th |
| The body plane that divides the body into equal left and right body section is called: | Mid-sagittal |
| The body plane that divides the body into anterior and posterior sections is called: | coronal |
| CT numbers are usually provided in the form of: | Hounsfield units (CT Units) |
| The CT "window" controls the ____________ of the CT image as it appears to the viewer. | contrast and brightness |
| Before a CT image can be reconstructed by a computer, the transmission signal produced by the detectors must be converted into numerical information by a(n): | analog-to-digital converter (ADC) |
| Which of the following archival media is capable of storing the largest number of CT images? | PACS |
| The continuous gantry rotation required by helical CT acquisition is made possible by the application of: | slip-rings |
| Pixels representing tissues with average attenuation coefficients greater than that of water have which of the following types of values? | positive |
| Fourth-generation CT scanners use a __________ tube-detector configuration. | rotate-stationary |
| Which of the following statements regarding pre-detector collimation of the CT x-ray beam is true? | Pre-detector collimation removes scatter radiation before it reaches the detectors. |
| When an operator reduces the scan field of view for a particular body part, which of the following technical changes occurs? The displayed image appears larger. Spatial resolution increases. The displayed image appears smaller. | The displayed image appears smaller. |
| First-generation CT scanners used a method of data acquisition based on a __________ principle. | translate-rotate |
| First-generation CT scanners possess which of the following characteristics? | pencil-thin x-ray beam |
| The reduction in intensity of an x-ray beam as it interacts with matter is called: | attenuation |
| Pixels whose average attenuation coefficients are less than the coefficient of water have which of the following types of CT number values? | negative |
| Which of the following actions would serve to magnify the CT image on the display monitor? decrease matrix size increase scan field of view decrease display field of view increase display field of view | decrease display field of view |
Created by:
JenGlez