A Ans✓✓✓ 11. The quality factor (QF) used for determining the dose
equivalence for high-energy x-rays
compared to high-energy gamma rays is:
A. 0.869.
B. 0.956.
C. 1.000.
D. 1.035.
A Ans✓✓✓ 15. The value for the Ngas calibration factor for an
ionization chamber will depend on the:
A. composition of the chamber wall.
B. temperature of the air in the chamber.
C. pressure of the air in the chamber
D. source to chamber distance.
A Ans✓✓✓ 19. Irradiation of which of the following structures is most
likely to result in symptomatic late
toxicity when treating pediatric neuroblastoma?
A. bone.
B. spleen.
C. spinal cord.
D. bladder.
, A Ans✓✓✓ 2. From the techniques listed below, select the least
desirable method for treating a 3cm non-
secreting pituitary adenoma.
A. opposed lateral fields
B. opposed laterals plus a vertex field
C. non-coplanar fields
D. stereotactic radiosurgery
A Ans✓✓✓ 22. An image on a radiograph measures 12 cm. The source
to object distance is 90 cm and
the source to film distance is 110 cm. The actual size of the object is:
A. 9.8 cm.
B. 10.8 cm.
C. 12.0 cm.
D. 12.8 cm.
A Ans✓✓✓ 24. Which of the following CT numbers (Hounsfield units) is
most closely related to air?
A. -1000
B. -750
C. 0