Chapter 36 Flashcards
Leakage radiation must be less then ____mR/hr at a distance of 1 m from the protective housing
100
The SID indicator must be accurate within __% of the indicated SID.
2
The x-ray beam and the light must beam must coincide within ___% of the SID
2
The PBL must be accurate to within ___ of the SID
2
The variation in x-ray intensity should not exceed ___%
5
The maximum acceptable variation in linearity is ___% from one mA station to an adjacent mA station.
10
The SSD must not be less than ___cm on stationary fluroscopes and not less then ___ cm on mobile fluroscope.
38, 30
___ time produces an audible signal when the fluroscopc time has exceeded 5 minutes
cumulative
What device is used to cover the opening on the side of a fluroscopic table when the bucky tray is moved out the way?
bucky slot cover
A ___ of at least 0.25mm Pb equivalent should be positioned between the fluroscopist and the patient
protective curtain
____ radiation is the useful beam.
primary
What are the two types of secondary radiation:
scatter and leakage
The intensity of scatter radiation 1 m from the patient is approximately __% of the intensity of the useful beam at the patient.
0.1
When PBL is activated, the collimators are automatically adjusted so that the radiation field matches the ____.
film size
What are the two type of filtration?
inherent and added
The glass envelope encasing the
x-ray tube, the insulating oil, and the glass window are examples of what type of filtration?
inherent
Inherent materials amounts to approximately __mm of aluminum equivalent.
0.5
A sheet of aluminum or its equivalent of appropriate thickness located outside the glass window of the tube housing above the collimator shutters are examples of what type of filtration?
added
Added filtration is __ mm of aluminum equivalent
1
The inherent and added filtration should combine to equal the required ___ of aluminum equivalent. (fixed tube, above 70kVp)
2.5
The variation in the x-ray intensity should not exceed _%
5
The maximum acceptable variation in linearity is __% from one mA station to an adjacent mA station
10
The x-ray control panel must show _____.
a. beam on time
b. mAs used
c. positive beam limitation
d. automatic exposure controls
A
What is the minimum requirement for filtration on x-ray equipment operating above 70 kVp?
a. 1.5 mm Al equivalent
b. 2.0 mm Al equivalent
c. 2.5 mm Al equivalent
d. 3.5 mm Al equivalent
c
- The output intensities of reproduced exposures should not vary more than _____% from each other.
a. 5
b. 10
c. 15
d. 20
A
- Measuring the relationship between the output intensities of adjacent mA stations is a test of _____.
a. HVL
b. beam limitation
c. reproducibility
d. linearity
D
- The source-to-skin distance must be no less than _____ cm on stationary fluoroscopes.
a. 30
b. 38
c. 42
d. 48
B
- The _____ is the primary protective barrier for the fluoroscopic x-ray tube.
a. ceiling
b. floor
c. image intensifier
d. table top
C
A fluoroscopy system with automatic collimation must provide an unexposed border around the image at _____ above the table top.
a. all heights
b. 35 cm
c. 25 cm
d. 18 cm
A
- The fluoroscopic exposure control switch is always a(n) _____ type.
a. rheostat
b. automatic
c. deadman
d. on-off
C
- The bucky slot opening in the side of the table must be automatically covered with _____ mm Pb during fluoroscopy.
a. 1.25
b. 1.0
c. 0.5
d. 0.25
D
- A cumulative timer is designed to _____ of fluoroscopy beam-on time.
a. make the radiologist aware
b. turn off the radiation every 5 minutes
c. prevent more than 10 minutes
d. shut down the system after 15 minutes
A
Primary radiation is _____.
a. leakage radiation
b. the scattered beam
c. the useful beam
d. all of the above
C
The intensity of scatter radiation 1 meter from the patient is approximately _____ of the intensity of the incident beam at the patient.
a. 0.01%
b. 0.1%
c. 10%
d. 50%
b
At the level of the tabletop, the intensity of the fluoroscopic beam should not exceed _____ for each mA of operation at 80 kVp.
a. .02 mGy/hr
b. 0.2 mGy/hr
c. 21 mGy/min
d. 0.21 mGy/min
C
- A controlled area is one occupied primarily by _____.
a. radiology personnel
b. patients
c. the general public
d. both A and B
D
- A secondary barrier is designed to absorb _____ radiation
a. leakage
b. scattered
c. primary
d. both A and B
D
- A quantity that reflects both dose and volume of tissue irradiated is the _____.
a. estimated skin exposure
b. dose area product
c. proportional region
d. Rem
B
- The design of an uncontrolled area in radiology is based on the NCRP recommended limit of _____ mGy/yr for the public.
a. 50
b. 10
c. 1
d. 0.5
C
- Devices designed to measure total accumulated radiation intensity are called _____.
a. dosimeters
b. integrators
c. scintillation detectors
d. photo cathodes
A
- Gas-filled radiation detectors are based on the _____.
a. thermoluminescence of crystals
b. photoemission of electrons
c. ionization of gas
d. scintillation of phosphors
C
- The _____ is used for precise calibration of the output intensity of diagnostic x-ray tubes.
a. G-M counter
b. ion chamber
c. scintillation detector
d. proportional counter
B
- A Geiger-Muller counter is a(n) _____.
a. scintillation detector
b. optically stimulated dosimeter
c. gas-filled detector
d. thermoluminescent dosimeter
C
Patient dose can be reduced by using\_\_\_ I. faster screen II. higher kvp III. increased distance a. I b. II only c. II & III d. I, II, and III
a
