MDCB Practice Test Exam Actual
Questions and Answers 2026
Which one of the following DVH results for a pancreatic treatment
plan of conventional fractionation meets QUANTEC recommended
dose tolerances? -
correct answer ✅25% of the stomach will receive 45Gy.
Which of the following is TRUE regarding clinical electron beams? -
correct answer ✅High energy electrons lose energy at a rate of
approximately 2 MeV per cm of water or soft tissue.
What factors are instrumental in determining the dose uniformity
in equally weighted parallel opposed beams? -
correct answer ✅beam energy, tissue inhomogeneity and patient
thickness
Which of the following computer algorithms can most accurately
account for the dose calculation uncertainty in the interface region
between inhomogeneous materials for photon calculations?
*used most often to create uniform dose with photons -
correct answer ✅Monte Carlo method
,MDCB Practice Test Exam Actual
Questions and Answers 2026
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: -
correct answer ✅helical LINAC
Which of the following is the best thermal neutron absorber? -
correct answer ✅boronated polyethylene
Relative skin dose from a megavoltage photon beam is increased by
which of the following? -
correct answer ✅increasing the thickness bolus material used
The risk of symptomatic radiation pneumonitis is:
*more "symptoms" with chemo -
correct answer ✅increased if certain chemotherapy agents are
used.
DVHs can confirm which of the following? -
correct answer ✅The normal tissue tolerances are respected.
,MDCB Practice Test Exam Actual
Questions and Answers 2026
When comparing identical (IMRT) treatment plans, one delivered
with sliding window and the other delivered with step-and-shoot,
the sliding window treatment will most likely have which of the
following? total MU / total tx time -
correct answer ✅higher / shorter
What will result if a photon field abuts an electron field at the skin
surface? -
correct answer ✅photon side hot spot, electron side cold spot
Isocentric, parallel opposed oblique fields with unequal depths may
result in: -
correct answer ✅a plan with isodose lines that are similar to a plan
with equal depths and unequally weighted beams.
What can cause increased skin dose in IMRT for prostate cancer? -
correct answer ✅carbon fiber couch
Which of the following processes best explains how a radiation
beam is delivered during stepand-shoot IMRT? -
correct answer ✅Radiation is only delivered while the MLC is
stopped.
, MDCB Practice Test Exam Actual
Questions and Answers 2026
Characteristics of MLC, in current medical LINACs, include which of
the following: -
correct answer ✅"scalloped" isodose curves in the penumbra
region.
Which of the following can be determined from the V20 obtained
from a DVH for both lungs? -
correct answer ✅volume of both lungs receiving 20 gy
To eliminate the divergence into the lung of both fields when
planning an intact breast treatment using isocentric medial and
lateral opposed fields, it would be necessary to: -
correct answer ✅match the posterior diverging beam edges.
Physical penumbra width is defined as the lateral distance between
which two isodose curves at the level of dmax?
*physical penumbra = geometric & transmission penumbra, so
lateral distance is wide -
correct answer ✅20% and 80%
Questions and Answers 2026
Which one of the following DVH results for a pancreatic treatment
plan of conventional fractionation meets QUANTEC recommended
dose tolerances? -
correct answer ✅25% of the stomach will receive 45Gy.
Which of the following is TRUE regarding clinical electron beams? -
correct answer ✅High energy electrons lose energy at a rate of
approximately 2 MeV per cm of water or soft tissue.
What factors are instrumental in determining the dose uniformity
in equally weighted parallel opposed beams? -
correct answer ✅beam energy, tissue inhomogeneity and patient
thickness
Which of the following computer algorithms can most accurately
account for the dose calculation uncertainty in the interface region
between inhomogeneous materials for photon calculations?
*used most often to create uniform dose with photons -
correct answer ✅Monte Carlo method
,MDCB Practice Test Exam Actual
Questions and Answers 2026
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: -
correct answer ✅helical LINAC
Which of the following is the best thermal neutron absorber? -
correct answer ✅boronated polyethylene
Relative skin dose from a megavoltage photon beam is increased by
which of the following? -
correct answer ✅increasing the thickness bolus material used
The risk of symptomatic radiation pneumonitis is:
*more "symptoms" with chemo -
correct answer ✅increased if certain chemotherapy agents are
used.
DVHs can confirm which of the following? -
correct answer ✅The normal tissue tolerances are respected.
,MDCB Practice Test Exam Actual
Questions and Answers 2026
When comparing identical (IMRT) treatment plans, one delivered
with sliding window and the other delivered with step-and-shoot,
the sliding window treatment will most likely have which of the
following? total MU / total tx time -
correct answer ✅higher / shorter
What will result if a photon field abuts an electron field at the skin
surface? -
correct answer ✅photon side hot spot, electron side cold spot
Isocentric, parallel opposed oblique fields with unequal depths may
result in: -
correct answer ✅a plan with isodose lines that are similar to a plan
with equal depths and unequally weighted beams.
What can cause increased skin dose in IMRT for prostate cancer? -
correct answer ✅carbon fiber couch
Which of the following processes best explains how a radiation
beam is delivered during stepand-shoot IMRT? -
correct answer ✅Radiation is only delivered while the MLC is
stopped.
, MDCB Practice Test Exam Actual
Questions and Answers 2026
Characteristics of MLC, in current medical LINACs, include which of
the following: -
correct answer ✅"scalloped" isodose curves in the penumbra
region.
Which of the following can be determined from the V20 obtained
from a DVH for both lungs? -
correct answer ✅volume of both lungs receiving 20 gy
To eliminate the divergence into the lung of both fields when
planning an intact breast treatment using isocentric medial and
lateral opposed fields, it would be necessary to: -
correct answer ✅match the posterior diverging beam edges.
Physical penumbra width is defined as the lateral distance between
which two isodose curves at the level of dmax?
*physical penumbra = geometric & transmission penumbra, so
lateral distance is wide -
correct answer ✅20% and 80%
