Chapter 35 Flashcards
Health physics is concerned with minimizing radiation dose to _____.
a. radiation physicists
b. radiation workers
c. the public
d. all of the above
d
The first radiation health physicists worked with _____.
a. the atom bomb
b. x-ray tubes
c. CT scanners
d. nuclear medicine
a
The three cardinal principals of radiation protection involve _____.
a. dose, shielding, and exposure
b. exposure, shielding, and ALARA
c. time, distance, and shielding
d. ALARA, time, and distance
c
Exposure is measured by multiplying _____ by _____.
a. shielding thickness, exposure time
b. exposure rate, exposure time
c. exposure rate, shielding thickness
d. exposure time, distance
b
If a technologist is exposed to 4 mGyt/hr for 45 minutes during a fluoroscopy exam, what will be her total exposure?
a. 1 mGyt
b. 2 mGyt
c. 3 mGyt
d. 4 mGyt
c
When using the inverse square law during fluoroscopy, the patient should be considered a(n) _____ source of radiation.
a. Area
b. Linear
c. Round
d. Point
d
If a technologist is receiving 2 mGyt/hr standing 1 foot from the patient during fluoroscopy, what is his rate of exposure when he steps back to a distance of 2 feet from the patient?
a. 0.50 mGyt/hr
b. 0.74 mGyt/hr
c. 1 mGyt/hr
d. 1.75 mGyt/hr
a
A tenth-value layer is equal to _____ half-value layers.
a. 1.2
b. 3.3
c. 5.5
d. 10.0
b
If the HVL in a radiology department is 0.25 mm Pb, then how thick should a shield be to reduce the technologists’ exposure to one fourth the incident scatter?
a. 0.125 mm Pb
b. 0.25 mm Pb
c. 0.5 mm Pb
d. 1.0 mm Pb
c
What is the NCRP?
a. National Council of Radiation Protection
b. National Council of Radiology Personnel
c. National Committee on Radiation Prevention
d. National Committee on Random Particles
a
The NCRP makes _____ regarding dose limits.
a. laws
b. recommendations
c. requirements
d. measurements
b
The dose limits established by the NCRP are derived from _____.
a. government laws
b. newspaper articles
c. NCRP research
d. BEIR and NSC reports
d
The NCRP publishes annual dose limits for _____ exposure.
a. public
b. occupational
c. prenatal
d. all of the above
d
Dose limits are based on a _____ dose-response relationship to radiation.
a. nonlinear, nonthreshold
b. linear, nonthreshold
c. linear, threshold
d. nonlinear, threshold
b
The dose limit for the general public is _____ the dose limit for occupational exposure.
a. 1/10
b. 1/5
c. 1/2
d. 3/4
a
The concept of effective dose accounts for the _____.
a. different types of radiation and RBE
b. relative radiosensitivity of various tissues and organs
c. the person’s distance from the source
d. both A and B
d
What is the best approach to occupational radiation exposure?
a. Maintain the annual dose limits.
b. Follow the concept of ALARA.
c. Reduce your exposure to half the NCRP dose limits.
d. Wear protective apparel at all times.
b
If the distance from the source exceeds 5 times the source diameter, it can be treated as _____
Point source
During fluroscopy, the radiologic technologist should remain as far from the patient as possible
..
One ___ is the thickness of absorber that reduces the radiation intensity to one tenth its original value.
TVL
___ is the equivalent whole body dose
Effective dose
We assume the occupational effective dose to be 10% of the monitor dose
…
Exposure = Exposure rate X Exposure Time
..
1 TVL = __HVL
3.3
Equivalent whole body dose is____ the to various organs and tissues.
weighted average of the radiation dose
Effective dose for occupational radiation exposure is based on the ____.
occupational radiation monitor
