MDCB ACTUAL EXAM QUESTIONS AND
CORRECT ANSWERS
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. - CORRECT ANSWERS D. 25% of the stomach will
receive 45 Gy.
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. - CORRECT ANSWERS D. pencil beams.
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. - CORRECT ANSWERS B. be more
serious with beams of smaller penumbra.
A radiation oncology department has a selection of 6, 10, and 18 MV photon beams. For a 7
beam prostate Intensity Modulated Radiation Therapy (IMRT) plan, it would be appropriate to
select a/an:
,A. 6 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the planning target volume (PTV).
B. 6 MV photon beam because it would deliver some neutron dose, but give the best dose
distribution to the PTV.
C. 10 MV photon beam because it would deliver a lower neutron dose than an 18 MV photon
beam and clinically acceptable doses to the bladder and rectum.
D. 10 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the PTV. - CORRECT ANSWERS A. 6 MV photon beam because it would
deliver no neutron dose and the lowest doses to the tissue outside the planning target volume
(PTV).
What can cause increased skin dose in IMRT for prostate cancer?
A. prone position
B. wedge under knees- a support device
C. use of high energy photons
D. carbon fiber couch - CORRECT ANSWERS D. carbon fiber couch
Characteristics of multileaf collimators, in current medical LINACs, include which of the
following:
A. accommodates all field sizes.
B. "scalloped" isodose curves in the penumbra region.
C. ability to conform to all possible field shapes.
D. inability to verify leaf shapes. - CORRECT ANSWERS B. "scalloped" isodose curves in the
penumbra region.
The minimum nominal distance a tissue compensator should be placed from the skin surface
without affecting the skin sparing effect is:
A. 5.0 cm.
B. 10.0 cm.
, C. 20.0 cm.
D. 25.0 cm. - CORRECT ANSWERS C. 20.0 cm.
When treating with electrons typical X-ray contamination dose to a patient ranges from
approximately:
A. 0.1% to 0.4%
B. 0.5% to 5%
C. 6% to 9%
D. 10% to 12% - CORRECT ANSWERS B. 0.5% to 5%
The most significant factor effecting calculation of dose with tissue inhomogeneity correction is:
(A) energy of the beam
(B) size of inhomogeneity
(C) depth of inhomogeneity - CORRECT ANSWERS (B) size of inhomogeneity
The five year cure rate for a prostate cancer tumor treated with primary radiation is:
(A) 5 - 10%
(B) 25 - 30%
(C) 50 - 70%
(D) 75 - 95% - CORRECT ANSWERS (D) 75 - 95%
A lung tumor is to be treated utilizing a 90 degree arc. For a target volume centered 6.0 cm
below the skin surface, how far below the skin surface should the isocenter be placed?
(A) 2.5 cm
(B) 6.0 cm
(C) 9.0 cm
CORRECT ANSWERS
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. - CORRECT ANSWERS D. 25% of the stomach will
receive 45 Gy.
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. - CORRECT ANSWERS D. pencil beams.
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. - CORRECT ANSWERS B. be more
serious with beams of smaller penumbra.
A radiation oncology department has a selection of 6, 10, and 18 MV photon beams. For a 7
beam prostate Intensity Modulated Radiation Therapy (IMRT) plan, it would be appropriate to
select a/an:
,A. 6 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the planning target volume (PTV).
B. 6 MV photon beam because it would deliver some neutron dose, but give the best dose
distribution to the PTV.
C. 10 MV photon beam because it would deliver a lower neutron dose than an 18 MV photon
beam and clinically acceptable doses to the bladder and rectum.
D. 10 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the PTV. - CORRECT ANSWERS A. 6 MV photon beam because it would
deliver no neutron dose and the lowest doses to the tissue outside the planning target volume
(PTV).
What can cause increased skin dose in IMRT for prostate cancer?
A. prone position
B. wedge under knees- a support device
C. use of high energy photons
D. carbon fiber couch - CORRECT ANSWERS D. carbon fiber couch
Characteristics of multileaf collimators, in current medical LINACs, include which of the
following:
A. accommodates all field sizes.
B. "scalloped" isodose curves in the penumbra region.
C. ability to conform to all possible field shapes.
D. inability to verify leaf shapes. - CORRECT ANSWERS B. "scalloped" isodose curves in the
penumbra region.
The minimum nominal distance a tissue compensator should be placed from the skin surface
without affecting the skin sparing effect is:
A. 5.0 cm.
B. 10.0 cm.
, C. 20.0 cm.
D. 25.0 cm. - CORRECT ANSWERS C. 20.0 cm.
When treating with electrons typical X-ray contamination dose to a patient ranges from
approximately:
A. 0.1% to 0.4%
B. 0.5% to 5%
C. 6% to 9%
D. 10% to 12% - CORRECT ANSWERS B. 0.5% to 5%
The most significant factor effecting calculation of dose with tissue inhomogeneity correction is:
(A) energy of the beam
(B) size of inhomogeneity
(C) depth of inhomogeneity - CORRECT ANSWERS (B) size of inhomogeneity
The five year cure rate for a prostate cancer tumor treated with primary radiation is:
(A) 5 - 10%
(B) 25 - 30%
(C) 50 - 70%
(D) 75 - 95% - CORRECT ANSWERS (D) 75 - 95%
A lung tumor is to be treated utilizing a 90 degree arc. For a target volume centered 6.0 cm
below the skin surface, how far below the skin surface should the isocenter be placed?
(A) 2.5 cm
(B) 6.0 cm
(C) 9.0 cm
