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MEDICAL AND DENTAL COUNCIL BOARD
(MDCB) EXAM NEWEST UPDATE 2026-2027
ALL QUESTIONS AND DETAILED SOLUTIONS
Which of the methods used to reduce the impact of respiratory motion in radiotherapy results
in a loss of resolution to tumor and normal organ delineation?
slow CT scanning
inhale and exhale breath-hold CT
four-dimensional CT
respiration-accelerated CT
slow CT scanning
Which of the following head positions reduce exposure to the eyes for a patient with cancer
of the maxillary antrum?
neutral
extended superiorly
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angled to the affected side
lowered inferiorly
extended superiorly
During which stage of mitosis do the chromosomes align across the equator of the spindle
fibers?
prophase
metaphase
anaphase
telophase
metaphase
A 1 milligram radium source has an activity of:
3.7^2 x 10^7 disintegrations per second (dps)
3.7 x 10^6 nCi
3.7 x 10^7 Becquerel (Bq)
3.7^10 x 103 Ci
3.7 x 10^7 Becquerel (Bq)
An algorithm often used for electron beam dose calculation is:
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scatter-air ratio (SAR) summations
Batho & Young corrections
Clarkson calculations
pencil beams
pencil beams
Any error in the placement of adjacent fields during radiotherapy treatment is most likely due
to:
be equally serious for beams of any penumbra
be more serious with beams of smaller penumbra
have no impact the treatment outcome
be more serious with beams of larger penumbra
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 IMRT plan, it would be appropriate to select a/an:
6 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the PTV.
6 MV photon beam because it would deliver some neutron dose, but give the best dose
distribution to the PTV.
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10 MV photon beam because it would deliver a lower neutron dose that an 18 MV photon
beam and clinically acceptable doses to the bladder and rectum.
10 MV photon beam because it would deliver no neutron dose and the lowest dose to the
tissue outside the PTV.
6 MV photon beam because it would deliver no neutron dose and the lowest doses to the tissue
outside the PTV.
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?
Higher total MU and longer total treatment time
Lower total MU and longer total treatment time
Higher total MU and shorter total treatment time
Lower total MU and shorter total treatment time
Higher total MU and shorter total treatment time
The most radiosensitive phase for mental retardation in the fetus from RT accidental exposure
is:
0-7 weeks
MEDICAL AND DENTAL COUNCIL BOARD
(MDCB) EXAM NEWEST UPDATE 2026-2027
ALL QUESTIONS AND DETAILED SOLUTIONS
Which of the methods used to reduce the impact of respiratory motion in radiotherapy results
in a loss of resolution to tumor and normal organ delineation?
slow CT scanning
inhale and exhale breath-hold CT
four-dimensional CT
respiration-accelerated CT
slow CT scanning
Which of the following head positions reduce exposure to the eyes for a patient with cancer
of the maxillary antrum?
neutral
extended superiorly
, Page 2 of 247
angled to the affected side
lowered inferiorly
extended superiorly
During which stage of mitosis do the chromosomes align across the equator of the spindle
fibers?
prophase
metaphase
anaphase
telophase
metaphase
A 1 milligram radium source has an activity of:
3.7^2 x 10^7 disintegrations per second (dps)
3.7 x 10^6 nCi
3.7 x 10^7 Becquerel (Bq)
3.7^10 x 103 Ci
3.7 x 10^7 Becquerel (Bq)
An algorithm often used for electron beam dose calculation is:
, Page 3 of 247
scatter-air ratio (SAR) summations
Batho & Young corrections
Clarkson calculations
pencil beams
pencil beams
Any error in the placement of adjacent fields during radiotherapy treatment is most likely due
to:
be equally serious for beams of any penumbra
be more serious with beams of smaller penumbra
have no impact the treatment outcome
be more serious with beams of larger penumbra
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 IMRT plan, it would be appropriate to select a/an:
6 MV photon beam because it would deliver no neutron dose and the lowest doses to the
tissue outside the PTV.
6 MV photon beam because it would deliver some neutron dose, but give the best dose
distribution to the PTV.
, Page 4 of 247
10 MV photon beam because it would deliver a lower neutron dose that an 18 MV photon
beam and clinically acceptable doses to the bladder and rectum.
10 MV photon beam because it would deliver no neutron dose and the lowest dose to the
tissue outside the PTV.
6 MV photon beam because it would deliver no neutron dose and the lowest doses to the tissue
outside the PTV.
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?
Higher total MU and longer total treatment time
Lower total MU and longer total treatment time
Higher total MU and shorter total treatment time
Lower total MU and shorter total treatment time
Higher total MU and shorter total treatment time
The most radiosensitive phase for mental retardation in the fetus from RT accidental exposure
is:
0-7 weeks
