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RAD107_wk10-12
| Question | Answer |
|---|---|
| With image intensification the light level is raised to ___________ vision. | photopic |
| The input phosphor converts _________ to _________. | x-rays; light |
| The output phosphor of the image intensifier is composed of ___________________. | zinc cadmium sulfide |
| Electrons hit the _______________ after exiting the anode. | output phosphor |
| The image intensifier improved fluoroscopy by increasing image _________________. | brightness |
| The ability of the eye to detect differences in brightness levels is termed ___________. | contrast perception |
| The number of light photons emitted within the image intensifier is ____________ to the amount of x-ray photons exiting the patient. | directly proportional |
| The kinetic energy of photoelectrons in the image intensifier is greatly increased by the __________ | potential difference across the tube |
| The _______________ is the product of the minification gain and the flux gain. | brightness gain |
| What is the milliamperage used during fluoroscopy? | 5 mA |
| The ratio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called _______ gain. | flux |
| Fluoroscopy was developed so that radiologists could view ______________ images. | dynamic |
| The ____________ in the image intensifier emits electrons when it is stimulated by light photons. | photocathode |
| X-rays that exit the patient and enter the image intensifier first interact with the _____ | input phosphor |
| Light produced at the output phosphor of the image intensifier has been increased __________ times in intensity. | 50 to 75 |
| Visual acuity in the eye is greatest at the ___________, where _____ are concentrated. | fovea centralis; cones |
| Image intensified fluoroscopy is performed at illumination levels similar to ________ | radiograph viewing |
| The _______ in the retina are stimulated by _______ light; the _______ are stimulated by _______ light | rods; low; cones; bright |
| The capability of an image intensifier to increase the illumination level of the image is called its _____________________. | brightness gain |
| An image intensifier tube is identified by the diameter of its ___________ | input phosphor |
| Television monitoring allows ________________ to be controlled electronically. | both brightness and contrast |
| Viewing the fluoroscopic image in magnification mode increases _________ | contrast resolution, spatial resolution, and patient dose |
| Automatic brightness control (ABC) maintains the brightness of the image by varying _________ | kVp and mA |
| Brightness gain is typically in the range of ________ | 5000 to 30,000 |
| Digital fluoroscopy with a charge-coupled device has lower _____________ and higher ______________ than conventional fluoroscopy. | patient dose; light sensitivity |
| The combination of temporal and energy subtraction techniques is called ______ | hybrid subtraction |
| In mask mode, the ________ image is shown on monitor B, and the ________ image is shown on monitor A. | mask; subtracted |
| Energy subtraction technique takes advantage of the difference in ______________ during contrast injection. | K-edge absorption |
| Digital fluoroscopy uses at least _____ monitor(s). | 2 |
| Digital fluoroscopy systems with hybrid capabilities use both _________________ | temporal and energy subtraction |
| The ______________ is responsible for supervising quality control. | chief radiologist |
| About 80% of breast cancer occurs in __________ tissue. | ductal |
| Soft tissue radiography requires special techniques because of the low ________ | subject contrast |
| Quality control procedures include measures of ____________ | display devices, repeat analysis and image receptor function |
| The purpose of a quality control program is to maintain the maximum ___________ with the minimum ________ | quality of mammograms; patient dose |
| The mammography quality control program is outlined by the __________ | Mammography Quality Standards Act |
| In soft tissue radiography, all of the tissues being imaged have similar ________ | effective atomic numbers, mass densities, and Compton interaction |
| When doing soft tissue radiography, the differential absorption between ________ and ______ must be enhanced. | muscle; fat |
| Every dedicated mammography unit is equipped with a __________ | low ratio grid |
| A diagnostic mammogram must be able to demonstrate microcalcifications less than _____ in size. | 500 μm |
| The principal drawback of the first-generation CT scanner was the ___________ | long scanning time |
| Each sweep of the source-detector around the body during CT is called a ______ | translation |
| Filtered back projection in CT refers to ________ | image reconstruction |
| The second-generation CT scanners had the disadvantage of increased __________ | beam scatter |
| Each CT projection is _________ | stored on the computer |
| The pixel size is reduced when the _______ size is increased and the _____________ size is fixed. | matrix; field of view |
| The cross-sectional anatomy is translated into ___________ during CT reconstruction. | a matrix of values |
| CT scanners operate on ________________ voltage generation. | high-frequency |
| The concentration of scintillation detectors affects the ___________ of the CT image. | spatial resolution |
| The new development in the fourth-generation CT scanner is the ________ | stationary detector assembly |
| Each CT projection records variations in __________________ | mass density and effective atomic number |
| The patient dose in CT is determined by the ________________ collimator. | prepatient |
| The first generation of computed tomography used ______ detector(s). | one |
| The third generation of CT scanners allowed for further reduction in ________ | scanning time and scattered radiation |
| Many CT x-ray tubes have the capacity for millions of _________ with each exam. | heat units |
| The time from the end of CT imaging to image appearance is called the ______ time. | reconstruction |
| What is the principal disadvantage of third-generation CT scanners? | Ring artifacts |
| The reduction in ____________ was the principal advantage of the second-generation CT scanners. | scanning time |
| Each pixel of information in the CT image contains numerical information in ___________ units. | Hounsfield |
| The __________ generation of CT scanners was the first to have the fan beam transect the entire patient at all times. | pitch |
| The degree of spatial resolution in any CT imaging system is limited to the size of the ________ | pixel |
| The CT scanner must be calibrated so that ____________ is at CT number zero. | water |
| CT imaging has excellent ______________ because of the narrow beam collimation. | contrast resolution |
| The time from the end of imaging to appearance of the image is known as _________ | reconstruction time |
| A high variation in pixel values in a homogeneous phantom is a measure of ________. | image noise |
| The x-ray source and the detector move ______________ for computed tomography. | synchronously |
| Reconstruction of any image at any z-axis projection is possible because of a mathematical process known as ________ | interpolation |
| A CT image is a ___________ or __________ image that is perpendicular to the long axis of the body. | transaxial; transverse |
| Image noise in CT scanning depends on ___________ | pixel size, detector efficiency, slice thickness (all of the options) |
| A technologist who passes the ARRT exam in cardiovascular and interventional radiography may add _____ after the RT (R). | (CV) |
| The most common risk for the angiography patient is ___________ | bleeding at the puncture site |
| The x-ray tube used for interventional radiologic procedures has a _________ | small target angle |
| The patient table is moved with a floor switch to maintain a _________ | sterile field |
| The focal spot used for magnification of small vessels cannot be larger than ____ mm | 0.3 |
| When imaging a flow of contrast from the abdomen to the feet, a ___________ is used. | stepping table |
| Serial radiography requires x-ray equipment with a ___________ | high power rating |
| The ___________ artery is the one most often accessed for arteriograms. | femoral |
| The use of ______________ reduces the risk of a drug reaction during angiographic procedures. | nonionic contrast |
| The size and construction of the _____________ determines the anode heat capacity. | anode disk |
| DRT data projections are expressed in which units? | Projections sampled per degree sweep |
| During digital radiographic tomosynthesis (DRT), what is the range of the sweep angle of the x-ray tube? | 10 to 50 degrees |
| Filtered backprojection is useful for ________________ because of the shorter reconstruction time. | screening examinations |
| Filtered back projection in DRT refers to ________ | image reconstruction |
| Blurred-ripple artifacts appear __________ | perpendicular to the x-ray tube sweep direction |
| Computer aided detection (CAD) is not an early application of artificial intelligence (AI) in DRT. (T/F) | False |
| Which of the following is an important sweep angle metric? | Scan time |
| What is the typical source to image receptor distance in DRT? | 60 to 100 cm |
| The first digital radiographic tomosynthesis (DRT) appeared in which modality? | Mammography |
| DMIST showed that contrast resolution is more important than spatial resolution for diagnostic efficacy. (T/F) | True |
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jetsetjes