MDCB Practice Set 3 - Test 9 2026
D - answer1. Which type(s) of DVH shows the volume receiving a dose within a
specified dose range?
A. integral
B. cumulative
C. organ
D. differential
D - answer2. Which one of the following dose volume histogram (DVH) results for a
pancreatic treatment plan
of conventional fractionation meets QUANTEC recommended dose tolerances?
A. 75% of the left kidney will receive 30 Gy.
B. 50% of the right kidney will receive 40 Gy.
C. 50% of the liver will receive 42 Gy.
D. 25% of the stomach will receive 45 Gy.
C - answer3. Which of the following choices is the correct descriptor of the internal
target volume (ITV), as
defined by the ICRU Report #62?
A. GTV + Breathing Motion + Setup Margin
B. CTV + Internal Motion + Setup Margin
C. (C) CTV + Internal Motion
D. (D) GTV + Breathing Motion
A - answer4. Which of the following is true regarding clinical electron beams?
A. High energy electrons lose energy at a rate of approximately 2 MeV per cm of water
or
soft tissue.
B. The depth of the 80% isodose occurs at approximately 1/4 of the electron energy in
MeV.
C. The depth of the 90% isodose occurs at approximately 1/3 of the electron energy in
MeV.
D. The practical range of electrons (in cm of water) is approximately 2 times the energy
in
MeV.
A - answer5. What factors are instrumental in determining the dose uniformity in equally
weighted parallel
opposed beams?
A. beam energy, tissue inhomogeneity and patient thickness
B. beam energy, patient thickness and tissue maximum ratio
C. beam flatness, patient thickness and collimator scatter
, D. patient thickness, inhomogeneity and collimator scatter
A - answer6. A patient is normally treated with 18 MV photons 100 cm SAD linear
accelerator. The machine
breaks down and the patient is moved to a 6 MV 100 cm SAD linear accelerator. Using
the same
patient set up, the medical dosimetrist should consider doing which of the following?
A. Recompute an isodose distribution
B. Recontour all normal structures
C. Change MLC blocking
D. Change the field size
B - answer7. Which of the following computer algorithms can most accurately account
for the dose
perturbation in the interface region between inhomogeneous materials?
A. power law tissue-air ratio (TAR) model
B. Monte Carlo method
C. pencil beam method
D. generalized batho correction
D - answer8. An algorithm often used for electron beam dose calculations is:
A. scatter-air ratio (SAR) summations.
B. Batho & Young corrections.
C. Clarkson calculations.
D. pencil beams.
C - answer9. An IMRT technique in which the patient is treated slice by slice by
intensity-modulated beams in a
manner analogous to CT imaging is called:
A. Step-and-Shoot Therapy.
B. Dynamic MLC Therapy.
C. Tomotherapy.
D. Isosynchronous Therapy.
B - answer10. Any error in the placement of adjacent fields during radiotherapy
treatment is most likely to:
A. be equally serious for beams of any penumbra.
B. be more serious with beams of smaller penumbra.
C. have no impact the treatment outcome.
D. be more serious with beams of larger penumbra.
C - answer11. Which one of the following is the best thermal neutron absorber?
A. stainless steel
B. lead
C. boronated polyethylene
D. concrete
D - answer1. Which type(s) of DVH shows the volume receiving a dose within a
specified dose range?
A. integral
B. cumulative
C. organ
D. differential
D - answer2. Which one of the following dose volume histogram (DVH) results for a
pancreatic treatment plan
of conventional fractionation meets QUANTEC recommended dose tolerances?
A. 75% of the left kidney will receive 30 Gy.
B. 50% of the right kidney will receive 40 Gy.
C. 50% of the liver will receive 42 Gy.
D. 25% of the stomach will receive 45 Gy.
C - answer3. Which of the following choices is the correct descriptor of the internal
target volume (ITV), as
defined by the ICRU Report #62?
A. GTV + Breathing Motion + Setup Margin
B. CTV + Internal Motion + Setup Margin
C. (C) CTV + Internal Motion
D. (D) GTV + Breathing Motion
A - answer4. Which of the following is true regarding clinical electron beams?
A. High energy electrons lose energy at a rate of approximately 2 MeV per cm of water
or
soft tissue.
B. The depth of the 80% isodose occurs at approximately 1/4 of the electron energy in
MeV.
C. The depth of the 90% isodose occurs at approximately 1/3 of the electron energy in
MeV.
D. The practical range of electrons (in cm of water) is approximately 2 times the energy
in
MeV.
A - answer5. What factors are instrumental in determining the dose uniformity in equally
weighted parallel
opposed beams?
A. beam energy, tissue inhomogeneity and patient thickness
B. beam energy, patient thickness and tissue maximum ratio
C. beam flatness, patient thickness and collimator scatter
, D. patient thickness, inhomogeneity and collimator scatter
A - answer6. A patient is normally treated with 18 MV photons 100 cm SAD linear
accelerator. The machine
breaks down and the patient is moved to a 6 MV 100 cm SAD linear accelerator. Using
the same
patient set up, the medical dosimetrist should consider doing which of the following?
A. Recompute an isodose distribution
B. Recontour all normal structures
C. Change MLC blocking
D. Change the field size
B - answer7. Which of the following computer algorithms can most accurately account
for the dose
perturbation in the interface region between inhomogeneous materials?
A. power law tissue-air ratio (TAR) model
B. Monte Carlo method
C. pencil beam method
D. generalized batho correction
D - answer8. An algorithm often used for electron beam dose calculations is:
A. scatter-air ratio (SAR) summations.
B. Batho & Young corrections.
C. Clarkson calculations.
D. pencil beams.
C - answer9. An IMRT technique in which the patient is treated slice by slice by
intensity-modulated beams in a
manner analogous to CT imaging is called:
A. Step-and-Shoot Therapy.
B. Dynamic MLC Therapy.
C. Tomotherapy.
D. Isosynchronous Therapy.
B - answer10. Any error in the placement of adjacent fields during radiotherapy
treatment is most likely to:
A. be equally serious for beams of any penumbra.
B. be more serious with beams of smaller penumbra.
C. have no impact the treatment outcome.
D. be more serious with beams of larger penumbra.
C - answer11. Which one of the following is the best thermal neutron absorber?
A. stainless steel
B. lead
C. boronated polyethylene
D. concrete
