ARRT RADIATION PROTECTION PRACTICE EXAM | QUESTIONS
AND ANSWERS | VERIFIED ANSWERS PLUS RATIONALES | EXAM
ALREADY GRADED A+ | LATEST EXAM
1. Which of the following is the most radiosensitive tissue in the human body?
A. Bone
B. Muscle
C. Gonads
D. Cartilage
Answer: C. Gonads
Rationale: Reproductive cells are highly radiosensitive because they are rapidly dividing and
undifferentiated, making them more susceptible to radiation damage.
2. The primary purpose of filtration in an x-ray tube is to:
A. Increase image contrast
B. Remove low-energy photons
C. Reduce scatter radiation
D. Increase patient dose
Answer: B. Remove low-energy photons
Rationale: Filtration removes low-energy photons that would be absorbed by the patient without
contributing to image formation, thereby reducing unnecessary dose.
3. Which radiation monitoring device provides the most immediate reading of exposure?
A. Film badge
B. TLD
C. OSL
D. Pocket dosimeter
Answer: D. Pocket dosimeter
Rationale: A pocket dosimeter provides real-time readings, allowing immediate assessment of
radiation exposure.
4. The ALARA principle stands for:
A. As Low As Radiation Allows
B. As Low As Reasonably Achievable
C. As Long As Radiation Applied
D. As Limited As Radiology Allows
,Answer: B. As Low As Reasonably Achievable
Rationale: ALARA is a radiation safety principle aimed at minimizing radiation exposure while
achieving necessary diagnostic quality.
5. Increasing kVp while decreasing mAs, while maintaining image receptor exposure, will
generally:
A. Increase patient dose
B. Increase contrast
C. Decrease penetration
D. Reduce patient dose
Answer: D. Reduce patient dose
Rationale: Using higher kVp and lower mAs reduces patient dose due to increased beam
efficiency.
6. The annual occupational effective dose limit for radiation workers is:
A. 50 mSv
B. 5 mSv
C. 100 mSv
D. 500 mSv
Answer: A. 50 mSv
Rationale: The NCRP recommends an annual effective dose limit of 50 mSv (5 rem) for
occupationally exposed workers.
7. Which type of radiation interaction is responsible for most scatter radiation in diagnostic
imaging?
A. Photoelectric effect
B. Pair production
C. Compton scattering
D. Coherent scattering
Answer: C. Compton scattering
Rationale: Compton scattering produces scattered photons and is the primary source of
occupational exposure.
8. A lead apron typically provides approximately what level of protection?
A. 25%
B. 50%
C. 75%
D. 90%
,Answer: D. 90%
Rationale: A 0.5 mm lead-equivalent apron attenuates approximately 90% of scatter radiation.
9. The dose limit to the lens of the eye for occupational workers per year is approximately:
A. 150 mSv
B. 50 mSv
C. 15 mSv
D. 500 mSv
Answer: A. 150 mSv
Rationale: The NCRP occupational limit for the lens of the eye is 150 mSv annually.
10. Which of the following reduces patient dose most effectively?
A. Increasing SID
B. Increasing grid ratio
C. Using proper collimation
D. Decreasing kVp
Answer: C. Using proper collimation
Rationale: Collimation reduces field size, decreases scatter production, and lowers patient dose.
11. The genetic significant dose refers to radiation dose to the:
A. Thyroid
B. Skin
C. Bone marrow
D. Gonads
Answer: D. Gonads
Rationale: The genetic significant dose measures radiation exposure to reproductive organs
affecting future generations.
12. Which of the following is considered a stochastic effect?
A. Cataract formation
B. Skin erythema
C. Cancer
D. Hair loss
Answer: C. Cancer
Rationale: Stochastic effects are probabilistic and include cancer and genetic mutations.
13. Doubling the distance from a radiation source will change exposure intensity by what
factor?
, A. 1/4
B. 1/2
C. Double
D. Triple
Answer: A. 1/4
Rationale: According to the inverse square law, intensity decreases by the square of the distance.
14. The minimum required total filtration for x-ray units operating above 70 kVp is:
A. 1.0 mm Al
B. 1.5 mm Al
C. 2.0 mm Al
D. 2.5 mm Al
Answer: D. 2.5 mm Al
Rationale: Federal regulations require at least 2.5 mm aluminum equivalent filtration for units
operating above 70 kVp.
15. Which organ is most sensitive during early pregnancy?
A. Liver
B. Fetus
C. Kidneys
D. Pancreas
Answer: B. Fetus
Rationale: The developing embryo/fetus is highly radiosensitive, particularly during
organogenesis.
16. The unit used to measure absorbed dose is:
A. Sievert
B. Gray
C. Coulomb/kg
D. Curie
Answer: B. Gray
Rationale: The gray (Gy) is the SI unit of absorbed dose.
17. The protective device used to shield the thyroid during imaging is called a:
A. Lead apron
B. Gonadal shield
C. Thyroid collar
D. Lead gloves
AND ANSWERS | VERIFIED ANSWERS PLUS RATIONALES | EXAM
ALREADY GRADED A+ | LATEST EXAM
1. Which of the following is the most radiosensitive tissue in the human body?
A. Bone
B. Muscle
C. Gonads
D. Cartilage
Answer: C. Gonads
Rationale: Reproductive cells are highly radiosensitive because they are rapidly dividing and
undifferentiated, making them more susceptible to radiation damage.
2. The primary purpose of filtration in an x-ray tube is to:
A. Increase image contrast
B. Remove low-energy photons
C. Reduce scatter radiation
D. Increase patient dose
Answer: B. Remove low-energy photons
Rationale: Filtration removes low-energy photons that would be absorbed by the patient without
contributing to image formation, thereby reducing unnecessary dose.
3. Which radiation monitoring device provides the most immediate reading of exposure?
A. Film badge
B. TLD
C. OSL
D. Pocket dosimeter
Answer: D. Pocket dosimeter
Rationale: A pocket dosimeter provides real-time readings, allowing immediate assessment of
radiation exposure.
4. The ALARA principle stands for:
A. As Low As Radiation Allows
B. As Low As Reasonably Achievable
C. As Long As Radiation Applied
D. As Limited As Radiology Allows
,Answer: B. As Low As Reasonably Achievable
Rationale: ALARA is a radiation safety principle aimed at minimizing radiation exposure while
achieving necessary diagnostic quality.
5. Increasing kVp while decreasing mAs, while maintaining image receptor exposure, will
generally:
A. Increase patient dose
B. Increase contrast
C. Decrease penetration
D. Reduce patient dose
Answer: D. Reduce patient dose
Rationale: Using higher kVp and lower mAs reduces patient dose due to increased beam
efficiency.
6. The annual occupational effective dose limit for radiation workers is:
A. 50 mSv
B. 5 mSv
C. 100 mSv
D. 500 mSv
Answer: A. 50 mSv
Rationale: The NCRP recommends an annual effective dose limit of 50 mSv (5 rem) for
occupationally exposed workers.
7. Which type of radiation interaction is responsible for most scatter radiation in diagnostic
imaging?
A. Photoelectric effect
B. Pair production
C. Compton scattering
D. Coherent scattering
Answer: C. Compton scattering
Rationale: Compton scattering produces scattered photons and is the primary source of
occupational exposure.
8. A lead apron typically provides approximately what level of protection?
A. 25%
B. 50%
C. 75%
D. 90%
,Answer: D. 90%
Rationale: A 0.5 mm lead-equivalent apron attenuates approximately 90% of scatter radiation.
9. The dose limit to the lens of the eye for occupational workers per year is approximately:
A. 150 mSv
B. 50 mSv
C. 15 mSv
D. 500 mSv
Answer: A. 150 mSv
Rationale: The NCRP occupational limit for the lens of the eye is 150 mSv annually.
10. Which of the following reduces patient dose most effectively?
A. Increasing SID
B. Increasing grid ratio
C. Using proper collimation
D. Decreasing kVp
Answer: C. Using proper collimation
Rationale: Collimation reduces field size, decreases scatter production, and lowers patient dose.
11. The genetic significant dose refers to radiation dose to the:
A. Thyroid
B. Skin
C. Bone marrow
D. Gonads
Answer: D. Gonads
Rationale: The genetic significant dose measures radiation exposure to reproductive organs
affecting future generations.
12. Which of the following is considered a stochastic effect?
A. Cataract formation
B. Skin erythema
C. Cancer
D. Hair loss
Answer: C. Cancer
Rationale: Stochastic effects are probabilistic and include cancer and genetic mutations.
13. Doubling the distance from a radiation source will change exposure intensity by what
factor?
, A. 1/4
B. 1/2
C. Double
D. Triple
Answer: A. 1/4
Rationale: According to the inverse square law, intensity decreases by the square of the distance.
14. The minimum required total filtration for x-ray units operating above 70 kVp is:
A. 1.0 mm Al
B. 1.5 mm Al
C. 2.0 mm Al
D. 2.5 mm Al
Answer: D. 2.5 mm Al
Rationale: Federal regulations require at least 2.5 mm aluminum equivalent filtration for units
operating above 70 kVp.
15. Which organ is most sensitive during early pregnancy?
A. Liver
B. Fetus
C. Kidneys
D. Pancreas
Answer: B. Fetus
Rationale: The developing embryo/fetus is highly radiosensitive, particularly during
organogenesis.
16. The unit used to measure absorbed dose is:
A. Sievert
B. Gray
C. Coulomb/kg
D. Curie
Answer: B. Gray
Rationale: The gray (Gy) is the SI unit of absorbed dose.
17. The protective device used to shield the thyroid during imaging is called a:
A. Lead apron
B. Gonadal shield
C. Thyroid collar
D. Lead gloves
