| Question | Answer |
| Photoelectric emission: | is the emission of electrons from an illuminated surface |
| at what stage of image intensified fluoroscopy is the number of image-forming photons lowest? | entering the input phosphor |
| image intensifier brightness gain increases with increasing: | flux gain |
| when an image intensifier receives x-rays at the input phosphor what is emitted at the output phosphor? | visible light |
| which of the following is the input phosphor of image intensifiers? | cesium iodide |
| which of the following is the output phosphor of image intensifiers? | zinc cadmium sulfide |
| which of the following is the component of the image intensifier responsible for focusing the electron beam?` | electrostatic lens |
| The ability of an image intensifier to enhance image illumination is called: | brightness gain |
| the magnification gain of an image intensifier increases with increasing: | input phosphor size |
| which of the following is a representative brightness gain for an image intensifier? | 20,000 |
| if an image intensifier is described as a 25/12 tube, 25/12 refers to which of the following? | diameter of the input phosphor in centimeters |
| when a multi focus image intensifier is operated in the magnification mode: | the electron focal point is closer to the input phosphor |
| an image that displays vignetting: | is dim around the periphery |
| with a multi focus image intensifier in the magnification mode: | spatial resolution is improved |
| What is the photoemissive component of image intensified fluoroscopy? | electrons from light |
| which of the following is photoconductive? | target |
| what is the principal disadvantage of coupling the television camera to the image intensifier with the use of fiber optics? | photospot camera cannot be used |
| which of the following refers to the image intensifier input phosphor? | cesium iodide |
| which is a critical component in optically coupling an image intensifier with a photospot camera? | objective lens |
| what is the most important component of a television monitor? | cathode ray tube |
| vertical television resolution is limited principally by which of the following? | lines per frame |
| the electron beam in a television camera tube is produced by which of the following means? | thermionic emission |
| what is the camera tube most used in television fluoroscopy? | vidicon |
| place the following in proper sequence for image intensified fluoroscopy:
1. electric signal to light
2. electrons to light
3. light to electric signal
4. light to electrons
5. xray to light | 5,4,2,3,1 |
| which of the following applies to the output phosphor? | light emitted |
| the bucky slot covers of a fluoroscopic unit is a:
a. cassette holder
b. film changer
c. film support device
d. protective device | d. protective device |
| the ratio of the number of light photons at the output phosphor to the number of X-rays at the input phosphor is the:
a. brightness gain
b. illumination gain
c. flux gain | c. |
| _________ refers to the time delay of moving the II and seeing the new image on the monitor.
a. film delay
b. image lag
c. phosphorescence | b. |
| warping and distortion at outer region of II due to a repulsion of electrons and the curvature of the II is called a :
a. brightness gain
b. minification
c.electrostatic charge
d. pincushion artifact | d. pincushion artifact |
| The II input phosphor is made of:
a. NaI
b. ZnCdS
c. TLD
d. CsI | d. |
| the II output phosphor is made of:
a. NaI
b. ZnCdS
c. TLD
d. CsI | B |
| the brightness gain of an II tube does NOT depend on the:
a. patient dose
b. efficiency of the photocathode
c. voltage across the tube | A |
| Typical values for modern IIs do not include:
a. minification gains of 100
b. flux gains of 50
c. contrast ratios of 2:1
d. brightness gains of 5000 | C |
| If the entrance skin exposure rate of an II operated in the 30-cm mode is 1 R/min, the ESE rate in the 15-cm mode would be:
A. 1/4 R/min
B. 1/2 R/min
C. unchanged
D. 2 R/min
E. 4 R/min | E |
| if a 25-cm diameter II has a brightness gain of 5,000 then the flux gain is approximately:
a. 500
b. 50
c. 5 | B |
| changing the magnification mode of an image intensifier from 30cm to 15cm in fluoroscopy will normally increase:
a. entrance skin exposure
b. distortion
c. vignetting
d. image brightness | a |
| the reason for interlacing two fields to form one frame in a conventional TV system is to reduce the:
a. patient dose
b. motion artifacts
c. quantum mottle
d. flicker | d |
| Vertical resolution of a standard north american TV is:
a. >horizontal resolution
b. .7x60 fields per second
c. .7x262.5 line pairs | c |
| the horizontal resolution of a TV system is primarily determined by the:
a. image brightness
b. bandwidth
c. number of TV lines | b. |
| the vertical resolution of a TV system is primarily determined by the:
a. image brightness
b. bandwidth
c. number of TV lines | c |
| in 35-mm cardiac cine, for a constant film density, patient entrance skin exposure is reduced by increasing the:
a. acquisition frame rate
b. kV
c. mA
d. grid ratio | b. kV |
| The limiting spatial resolution in fluoroscopy can be improved by increasing the:
a. grid ratio
b. II input size
c. radiation dose level
d. kV
e. none of the above | e |
| T or F? fluoroscopic xray tubes are designed to operate for longer periods of time at much lower mA, as compared to a typical diagnostic tube | true |
| T or F? fluoroscopy doesn't require the use of a grid | false |
| T or F? angiographic xray tubes are different from general diagnostic imaging tubes in that the tubes must be able to withstand increased heat units while providing excellent detail | true |
| T or F? states are permitted to have a more strict regulatory requirement on X-ray equipment than the federal government requires | true |
| T or F? exceeding 10R/min is permitted by federal and state law in certain circumstances | true |
| t or f? for an image intensifier, the composition of the output phosphor is typically the same as the composition of the input phosphor | false |
| t or f? the typical kV range in a fluoroscopic tube as compared to a diagnostic tube, is similar | true |
| t or f? the fluoroscopic tube is typically below the patient's table | true |
| t or f? quantum mottle is a blotchy or grainy appearance caused by excessive radiation to create a uniform image | false, caused by not enough radiation |
| t or f? the patient's table is the greatest source of scatter in a fluoroscopic procedure | false, the patient is |
| The input screen absorbs ____ and emits ________. | xray photons, light photons |
| electrostatic lenses are used to accelerate and focus:
a. light photons
b. xray photons
c. electrons | c |
| the II output phosphor is made of :
a. NaI
b. TLD
c. ZnCdS | c |
| standard fluoroscopic mA range is commonly:
a. .5-5.0
b. 5-10
c. 10-100 | a |
| the photocathode absorbs ______ and emits ________. | light photons; electrons |
| the edge distortion problem in image intensification tubes is called:
A. magnification
b. minification
c. vignetting | c |
| for a stationary fluoro xray unit, the focal spot of the X-ray tube must be at least ____ away from the entrance point of the patient | 12" (30cm) |
| for a c-arm fluoro X-ray unit, the focal spot of the X-ray tube must be at least ____ away from the entrance point of the patient | 12" (30cm) |
| for lead aprons, the minimum allowed lead equivalency thickness required by law is _____mm | 0.25 mm |
| in fluoroscopy, when the image intensifier button is selected for magnification, the method by which magnification is accomplished is by: | moving the focal point of the electrons accelerated in the II away from the output phosphor |
| the purpose and function of an image intensifier as used in fluoro is to:
a. convert X-rays to electrons
b. act as a phosphor to expose film
c. convert one X-ray at the input into thousands of light photons at the output | c |
| this type of camera operated by recording a series of static images at high speed:
a. cine camera
b. cinema-type
c. photomulitplier
d. image intensifier | a |
| the input phosphor of an image intensifier is composed of _____ and the output phosphor is composed of ______.
a. CsI; CsI
b. CsI; ZnCdS
c. ZnCdS; Csl | b |
| ________ refers to the time delay of moving the II and seeing the new image on the monitor.
a. flicker
b. cine
c. lapse
d. lag | d |
| fluoroscopy is a _______ radiographic examination.
a. dynamic
b. screening
c. static
d. more than one of the above | a |
| fluoroscopy is mainly operated by the:
a. radiographer
b. radiologist
c. physicist | a |
