Radiation Therapy Board Review Exam
Questions with Verified Answers
Question 1
How is the 4D modality different from the 3D modality?
A. 4D uses MLC's
B. 4D makes use of the CT scanner
C. 4D accounts for relaxation and role movement
D. 4D accounts for target movement during treatment
Correct Answer
D. 4D accounts for target movement during treatment
Question 2
Which of the following dental reactions is common when irradiating the oral cavity?
A. Neuropathy
B. Plaque
C. Caries
D. Discoloration
Correct Answer
C. Caries
Radiation promotes tooth decay In already compromised teeth.
Page 1 of 442
,Question 3
A TBI patient will be treated on a 100 cm isocentric accelerator at a distance of 450
cm. The calibrated dose rate at isocenter is 250 cGy/minute. The dose rate at the
treatment distance is:
A. 55.5 cGy/min
B. 1125 cGy/min
C. 62.5 cGy/min
D. 12 cGy/min
Correct Answer
D. 12 cGy/min
Use the inverse square law:
(250/x) = (450/100)^2
(250)(100)^2 = 2,500,000
(x)(450)^2 = 202,500
2,500,000/202,500 = 12.3
Question 4
Which of the following for photon beams allow you to set the collimator field size?
A. Primary collimators
B. Secondary collimators
C. Xray target
D. Electron applicator
Correct Answer
B. Secondary collimators
Page 2 of 442
,Question 5
A 360 degree rotation has an MU/degree of 0.72 MU/degree. How many monitor
units will be delivered?
A. 180
B. 200
C. 259
D. 360
Correct Answer
C. 259
360 x 0.72 = 259
Question 6
The half life of I-125 is 60 days. In six months, the activity of the source will be ___ of
the original.
A. 70%
B. 50%
C. 1/8
D. 5%
E. 1/64
Correct Answer
C. 1/8
One half like is 60 days. There are three half lives in 6 months. Three half lives
decrease the activity to 1/8 of the original.
Question 7
When transporting a patient with a chest drainage tube, you should:
A. Make sure there are no kinks in the tube
B. Place the bottle on the patient's chest
C. Clamp off the tube
D. All of the above
Correct Answer
A. Make sure there are no kinks in the tube
Page 3 of 442
, Question 8
The normal range of platelets in the adult is:
A. 5 - 10 thousand/mm^3
B. 4 - 6 million/mm^3
C. 5 - 10 million/mm^3
D. 150 - 500 thousand/mm^3
Correct Answer
D. 150 - 500 thousand/mm^3
Question 9
Which of the following would influence the onset or duration of action for a certain
drug?
A. Purity
B. Kidney function
C. Nutrition
D. Liver function
Correct Answer
C. Nutrition
Question 10
In the treatment of head and neck cancer, dosimetry corrections for the presence of
bone and sinuses are most important for:
A.60Co gamma rays
B. 4MV
C. 6MV
D. 12 MeV electrons
E. Equally important for all these
Correct Answer
D. 12 MeV electrons
Page 4 of 442
Questions with Verified Answers
Question 1
How is the 4D modality different from the 3D modality?
A. 4D uses MLC's
B. 4D makes use of the CT scanner
C. 4D accounts for relaxation and role movement
D. 4D accounts for target movement during treatment
Correct Answer
D. 4D accounts for target movement during treatment
Question 2
Which of the following dental reactions is common when irradiating the oral cavity?
A. Neuropathy
B. Plaque
C. Caries
D. Discoloration
Correct Answer
C. Caries
Radiation promotes tooth decay In already compromised teeth.
Page 1 of 442
,Question 3
A TBI patient will be treated on a 100 cm isocentric accelerator at a distance of 450
cm. The calibrated dose rate at isocenter is 250 cGy/minute. The dose rate at the
treatment distance is:
A. 55.5 cGy/min
B. 1125 cGy/min
C. 62.5 cGy/min
D. 12 cGy/min
Correct Answer
D. 12 cGy/min
Use the inverse square law:
(250/x) = (450/100)^2
(250)(100)^2 = 2,500,000
(x)(450)^2 = 202,500
2,500,000/202,500 = 12.3
Question 4
Which of the following for photon beams allow you to set the collimator field size?
A. Primary collimators
B. Secondary collimators
C. Xray target
D. Electron applicator
Correct Answer
B. Secondary collimators
Page 2 of 442
,Question 5
A 360 degree rotation has an MU/degree of 0.72 MU/degree. How many monitor
units will be delivered?
A. 180
B. 200
C. 259
D. 360
Correct Answer
C. 259
360 x 0.72 = 259
Question 6
The half life of I-125 is 60 days. In six months, the activity of the source will be ___ of
the original.
A. 70%
B. 50%
C. 1/8
D. 5%
E. 1/64
Correct Answer
C. 1/8
One half like is 60 days. There are three half lives in 6 months. Three half lives
decrease the activity to 1/8 of the original.
Question 7
When transporting a patient with a chest drainage tube, you should:
A. Make sure there are no kinks in the tube
B. Place the bottle on the patient's chest
C. Clamp off the tube
D. All of the above
Correct Answer
A. Make sure there are no kinks in the tube
Page 3 of 442
, Question 8
The normal range of platelets in the adult is:
A. 5 - 10 thousand/mm^3
B. 4 - 6 million/mm^3
C. 5 - 10 million/mm^3
D. 150 - 500 thousand/mm^3
Correct Answer
D. 150 - 500 thousand/mm^3
Question 9
Which of the following would influence the onset or duration of action for a certain
drug?
A. Purity
B. Kidney function
C. Nutrition
D. Liver function
Correct Answer
C. Nutrition
Question 10
In the treatment of head and neck cancer, dosimetry corrections for the presence of
bone and sinuses are most important for:
A.60Co gamma rays
B. 4MV
C. 6MV
D. 12 MeV electrons
E. Equally important for all these
Correct Answer
D. 12 MeV electrons
Page 4 of 442
