RADIATION THERAPY FINAL EXAM 2026/2027 QUESTIONS
AND SOLUTIONS RATED A+
✔✔Which best describe what a 3D plan is not:
A. DVH analysis
B. A single, open treatment beam
C. Multiple fields
D. Static MLC's - ✔✔B. A single, open treatment beam
✔✔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 - ✔✔D. 4D accounts for target
movement during treatment
✔✔IMRT sometimes uses arc fields.
A. True
B. False - ✔✔A. True
✔✔SRS treatments are typically given in 5 consecutive days.
A. True
B. False - ✔✔B. False
✔✔The field light on the linear accelerator is intended to represent:
A. The area of radiation exposure
B. The size of the target
C. The width, length, and depth of the treatment
D. The distance from the source of radiation to the patient's skin - ✔✔A. The area of
radiation exposure
✔✔A mechanical distance indicator is used to verify:
A. Gantry rotation
B. Collimator rotation
C. Field size congruence
D. Accuracy of the optical distance indicator - ✔✔D. Accuracy of the optical distance
indicator
,✔✔When a missing tissue compensator is used in a photon beam, the compensator
should be:
A. Placed at some distance from the skin surface
B. Placed directly on the skin surface to be most effective
C. Made the same size as the missing tissue volume and be placed at some distance
from the skin surface
D. Placed directly on the skin surface to take advantage of the skin soaring properties of
a compensator - ✔✔B. Placed directly on the skin surface to be most effective
✔✔A patient's separation is measured 32 cm in the AP/PA protection. An anterior SSD
of 90 cm is measured with a 100 cm SAD treatment machine. The posterior SSD should
be:
A. 100 cm
B. 88 cm
C. 86 cm
D. 78 cm - ✔✔D. 78 cm
✔✔Why do we use electron treatments?
A. Increase beam penetration
B. To compensate for missing tissue
C. Increases the surface dose
D. Increase electron contamination
E. A & C - ✔✔C. Increases the surface dose
✔✔What is the acceptable amount of primary beam transmission through MLC's?
A. 1-2%
B. 0%
C. 98%
D. 100%
E. 0.2% - ✔✔A. 1-2%
✔✔Which of the following techniques may be used to adequately irradiate the internal
mammary lymph nodes while limiting exposure to other organs?
A. AP 6MV only
B. AP photon/electron combo
C. AP 6 MeV only
D. Extended medial tangent - ✔✔B. AP photon/electron combo
✔✔The gantry is angled ____ while treating the S/clav field?
,A. 0 degrees
B. 5-10 degrees
C. 10-15 degrees
D. 15-20 degrees - ✔✔C. 10-15 degrees
✔✔If a woman presents with a right lower outer quadrant tumor, state the typical
lymphatic drainage?
A. IM, axillary level 3, S/clav
B. Axillary level 1, axillary level 2, axillary level 3, S/clav
C. Transpectoral, axillary level 3, S/clav
D. Axillary level 3, axillary level 2, axillary level 1, S/clav - ✔✔B. Axillary level 1, axillary
level 2, axillary level 3, S/clav
✔✔Patient undergoing irradiation for Breast cancer can be treated?
1. Lithotomy position
2. Supine position
3. Prone position
4. Decubitus position
A. 1 only
B. 2 only
C. 1 & 2
D. 2 & 3
E. 1, 2, & 3
F. 2, 3, & 4 - ✔✔F. 2, 3, & 4
✔✔Lung correction factors depend on all of the following EXCEPT:
A. Beam energy
B. Electron density of lung
C. Depth of lung traversed by the beam
D. SSD
E. Distance from lung to point of calculation - ✔✔D. SSD
✔✔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 - ✔✔D. 12 MeV electrons
, ✔✔If 203 monitor units deliver 180 cGy, how many monitor units will deliver 250 cGy?
A. 250
B. 273
C. 282
D. 300 - ✔✔C. 282
203/180 = 1.127
1.127 x 250 = 281.9 = 282 cGy
✔✔You have a shortcut sheet with monitor units for the delivery of 100 cGy. For a field
size of 15 x 21 at a depth of 9cm the monitor units required are 125. If the dose to be
delivered for this field size and depth is 150 cGy, what will the monitor units be?
A. 55
B. 83
C. 188
D. 281 - ✔✔C. 188
125/100 = 1.25
1.25 x 150 = 187.5 = 188 Mu
✔✔The prescription says to deliver 50 Gy total. This is equivalent to how many rads?
A. 0.50
B. 5o
C. 500
D. 5000 - ✔✔D. 5000
The rad is the old unit for absorbed dose and 1 rad is equivalent to 1 cGy.
50 Gy = 5000 cGy = 5000 rads
✔✔A 10 x 10 cm lung field has a blocked area that is 2 x 5 cm. The blocked equivalent
is:
A. 8 x 8
B. 8 x 5
C. 9.5 x 9.5
D. 12 x 15 - ✔✔C. 9.5 x 9.5
10(10) - 2(5) = 100 - 10 = 90
AND SOLUTIONS RATED A+
✔✔Which best describe what a 3D plan is not:
A. DVH analysis
B. A single, open treatment beam
C. Multiple fields
D. Static MLC's - ✔✔B. A single, open treatment beam
✔✔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 - ✔✔D. 4D accounts for target
movement during treatment
✔✔IMRT sometimes uses arc fields.
A. True
B. False - ✔✔A. True
✔✔SRS treatments are typically given in 5 consecutive days.
A. True
B. False - ✔✔B. False
✔✔The field light on the linear accelerator is intended to represent:
A. The area of radiation exposure
B. The size of the target
C. The width, length, and depth of the treatment
D. The distance from the source of radiation to the patient's skin - ✔✔A. The area of
radiation exposure
✔✔A mechanical distance indicator is used to verify:
A. Gantry rotation
B. Collimator rotation
C. Field size congruence
D. Accuracy of the optical distance indicator - ✔✔D. Accuracy of the optical distance
indicator
,✔✔When a missing tissue compensator is used in a photon beam, the compensator
should be:
A. Placed at some distance from the skin surface
B. Placed directly on the skin surface to be most effective
C. Made the same size as the missing tissue volume and be placed at some distance
from the skin surface
D. Placed directly on the skin surface to take advantage of the skin soaring properties of
a compensator - ✔✔B. Placed directly on the skin surface to be most effective
✔✔A patient's separation is measured 32 cm in the AP/PA protection. An anterior SSD
of 90 cm is measured with a 100 cm SAD treatment machine. The posterior SSD should
be:
A. 100 cm
B. 88 cm
C. 86 cm
D. 78 cm - ✔✔D. 78 cm
✔✔Why do we use electron treatments?
A. Increase beam penetration
B. To compensate for missing tissue
C. Increases the surface dose
D. Increase electron contamination
E. A & C - ✔✔C. Increases the surface dose
✔✔What is the acceptable amount of primary beam transmission through MLC's?
A. 1-2%
B. 0%
C. 98%
D. 100%
E. 0.2% - ✔✔A. 1-2%
✔✔Which of the following techniques may be used to adequately irradiate the internal
mammary lymph nodes while limiting exposure to other organs?
A. AP 6MV only
B. AP photon/electron combo
C. AP 6 MeV only
D. Extended medial tangent - ✔✔B. AP photon/electron combo
✔✔The gantry is angled ____ while treating the S/clav field?
,A. 0 degrees
B. 5-10 degrees
C. 10-15 degrees
D. 15-20 degrees - ✔✔C. 10-15 degrees
✔✔If a woman presents with a right lower outer quadrant tumor, state the typical
lymphatic drainage?
A. IM, axillary level 3, S/clav
B. Axillary level 1, axillary level 2, axillary level 3, S/clav
C. Transpectoral, axillary level 3, S/clav
D. Axillary level 3, axillary level 2, axillary level 1, S/clav - ✔✔B. Axillary level 1, axillary
level 2, axillary level 3, S/clav
✔✔Patient undergoing irradiation for Breast cancer can be treated?
1. Lithotomy position
2. Supine position
3. Prone position
4. Decubitus position
A. 1 only
B. 2 only
C. 1 & 2
D. 2 & 3
E. 1, 2, & 3
F. 2, 3, & 4 - ✔✔F. 2, 3, & 4
✔✔Lung correction factors depend on all of the following EXCEPT:
A. Beam energy
B. Electron density of lung
C. Depth of lung traversed by the beam
D. SSD
E. Distance from lung to point of calculation - ✔✔D. SSD
✔✔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 - ✔✔D. 12 MeV electrons
, ✔✔If 203 monitor units deliver 180 cGy, how many monitor units will deliver 250 cGy?
A. 250
B. 273
C. 282
D. 300 - ✔✔C. 282
203/180 = 1.127
1.127 x 250 = 281.9 = 282 cGy
✔✔You have a shortcut sheet with monitor units for the delivery of 100 cGy. For a field
size of 15 x 21 at a depth of 9cm the monitor units required are 125. If the dose to be
delivered for this field size and depth is 150 cGy, what will the monitor units be?
A. 55
B. 83
C. 188
D. 281 - ✔✔C. 188
125/100 = 1.25
1.25 x 150 = 187.5 = 188 Mu
✔✔The prescription says to deliver 50 Gy total. This is equivalent to how many rads?
A. 0.50
B. 5o
C. 500
D. 5000 - ✔✔D. 5000
The rad is the old unit for absorbed dose and 1 rad is equivalent to 1 cGy.
50 Gy = 5000 cGy = 5000 rads
✔✔A 10 x 10 cm lung field has a blocked area that is 2 x 5 cm. The blocked equivalent
is:
A. 8 x 8
B. 8 x 5
C. 9.5 x 9.5
D. 12 x 15 - ✔✔C. 9.5 x 9.5
10(10) - 2(5) = 100 - 10 = 90
