Deck 36: Designing for Radiation Protection

Question 1

The output intensities of reproduced exposures should not vary more than _____% from each other.

A) 5
B) 10
C) 15
D) 20

Answer 1

5

Question 2

The source-to-skin distance must be no less than _____ cm on stationary fluoroscopes.

A) 30
B) 38
C) 42
D) 48

Answer 2

38

Question 3

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

Answer 3

all heights

Question 4

Primary radiation is _____.

A) leakage radiation
B) the scattered beam
C) the useful beam
D) all of the above

Question 5

The leakage radiation limit for x-ray tubes is less than _____ mGy/hr at 1 meter from the tube housing.

A) 0.50
B) 1
C) 2
D) 3

Question 6

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%

Question 7

Measuring the relationship between the output intensities of adjacent mA stations is a test of _____.

A) HVL
B) beam limitation
C) reproducibility
D) linearity

Question 8

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

Question 9

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

Question 10

The x-ray control panel must show _____.

A) beam on time
B) mAs used
C) positive beam limitation
D) automatic exposure controls

Question 11

Positive beam limitation must be accurate to within _____% of the SID.

A) 10
B) 5
C) 2
D) 1

Question 12

The _____ is the primary protective barrier for the fluoroscopic x-ray tube.

A) ceiling
B) floor
C) image intensifier
D) table top

Question 13

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

Question 14

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

Question 15

The fluoroscopic exposure control switch is always a(n)_____ type.

A) rheostat
B) automatic
C) deadman
D) on-off

Question 16

A secondary barrier is designed to absorb _____ radiation

A) leakage
B) scattered
C) primary
D) both A and B

Question 17

The collimator light must be accurate to within _____% of the SID.

A) 10
B) 5
C) 2
D) 1

Question 18

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

Question 19

A controlled area is one occupied primarily by _____.

A) radiology personnel
B) patients
C) the general public
D) both A and B

Question 20

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

Question 21

Devices designed to measure total accumulated radiation intensity are called _____.

A) dosimeters
B) integrators
C) scintillation detectors
D) photo cathodes

Question 22

A Geiger-Muller counter is a(n)_____.

A) scintillation detector
B) optically stimulated dosimeter
C) gas-filled detector
D) thermoluminescent dosimeter

Question 23

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

Question 24

The advantage(s)of using thermoluminescent dosimeters is/are:
I. small size
II. immediate results
III. tissue equivalent response

A) I & II.
B) II only
C) II & III
D) I & III

Question 25

Gas-filled radiation detectors are based on the _____.

A) thermoluminescence of crystals
B) photoemission of electrons
C) ionization of gas
D) scintillation of phosphors