MDCB review Exam Questions and
Answers Graded A+
1625 yr - Correct answer-Ra-226 half life
3.8 d - Correct answer-Rn-222 half life
5.3y - Correct answer-Co-60 half life
30y - Correct answer-Cs-137 half life
74 d - Correct answer-Ir-192 hald life
27 d - Correct answer-Au-198 half life
60d - Correct answer-I-125 half lfie
17d - Correct answer-Pd-103 half life
8d - Correct answer-I-131 half life
13GY - Correct answer-Spinal cord Dmax SRS 1 fx
12mm Pb - Correct answer-Ra-226 HVL
12 mmPb - Correct answer-Rn-222 HVL
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,11 mmPb - Correct answer-Co-60 HVL
5.5 mmPb - Correct answer-Cs-137 HVL
2.5 mmPb - Correct answer-Ir-192 HVL
2.5 mmPb - Correct answer-Au-198 HVL
0.025 mmPb - Correct answer-I-125 HVL
0.008 mmPb - Correct answer-Pd-103 HVL
E/3.2 - Correct answer-D90
E/2.8 - Correct answer-D80
<10% - Correct answer-V20 for lungs for SBRT
<12.5Gy - Correct answer-Brainstem SRS 1 fx Dmax
Co-60, Teletherapy, GammaKnife, HDR, Prostate Seed Implant - Correct answer-
List in order amount of activity from highest to lowest:
HDR, Co-60, Teletherapy, GammaKnife, Prostate Seed Implant
RX isodose Volume/PTV Volume - Correct answer-Conformity Index
<10% - Correct answer-Heart V25
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
,D2 - Correct answer-Maximum total dose in Gy to any point 2cm or greater away
from the PTV in any direction
V12<5-10cc - Correct answer-Brain volume SRS 1 fx
2mm; 1 degree - Correct answer-TG-142 suggests monthly QA tolerances for
lateral, longitudinal, and rotational couch positions for IMRT to be
2mm, 1% on a side - Correct answer-TG-142 suggests monthly QA tolerances for
mechanical/light field coincidence for IMRT to be
2% - Correct answer-TG-142 suggests monthly QA tolerances for electron output
constancy for IMRT to be
R50 - Correct answer-the ratio of the volume of 50% of the prescription dose
isodose to the volume of the PTV
2mm - Correct answer-TG-40 suggests daily QA tolerances for laser localization
for simulators to be
2mm - Correct answer-TG-40 suggests annual QA for medical accelerator
tolerances for gantry rotation isocenter to be
<32% - Correct answer-Kidney V20
E, FS, d, SSD - Correct answer-PDD is dependent on
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
, E, FS, d - Correct answer-TMR is dependent on
3.7 x 10^10 Bq - Correct answer-1 Ci =? Bq
10^6 - Correct answer-mega (M)
alpha particle, 1MV, 250kVp, Co-60 - Correct answer-Rank LET from highest to
lowest: 1MV, alpha particle, 250kVp, Co-60
1mSv - Correct answer-100mrad = ? dose equivalent
<12 Gy - Correct answer-Optic Nerve/Chiasm SRS 1 fx Dmax
target, Primary collimator, flattening filter, dose chambers, secondary collimator -
Correct answer-What is the correct order of components in treatment head to
generate x-rays?
6Mv - Correct answer-Which linac energy requires the highest beam current
Leukemia - Correct answer-Which is considered a stochastic effect?
Cataracts, Erythema, Sterility, Leukemia
Slightly greater - Correct answer-The lateral penumbra of a proton field is ______
as compared to a photon field.
55Gy - Correct answer-What is the ideal dose limit to 0.03cc of the brainstem?
Depth, FS, E - Correct answer-TMR are dependent on what?
©COPYRIGHT 2025, ALL RIGHTS RESERVED 4
Answers Graded A+
1625 yr - Correct answer-Ra-226 half life
3.8 d - Correct answer-Rn-222 half life
5.3y - Correct answer-Co-60 half life
30y - Correct answer-Cs-137 half life
74 d - Correct answer-Ir-192 hald life
27 d - Correct answer-Au-198 half life
60d - Correct answer-I-125 half lfie
17d - Correct answer-Pd-103 half life
8d - Correct answer-I-131 half life
13GY - Correct answer-Spinal cord Dmax SRS 1 fx
12mm Pb - Correct answer-Ra-226 HVL
12 mmPb - Correct answer-Rn-222 HVL
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,11 mmPb - Correct answer-Co-60 HVL
5.5 mmPb - Correct answer-Cs-137 HVL
2.5 mmPb - Correct answer-Ir-192 HVL
2.5 mmPb - Correct answer-Au-198 HVL
0.025 mmPb - Correct answer-I-125 HVL
0.008 mmPb - Correct answer-Pd-103 HVL
E/3.2 - Correct answer-D90
E/2.8 - Correct answer-D80
<10% - Correct answer-V20 for lungs for SBRT
<12.5Gy - Correct answer-Brainstem SRS 1 fx Dmax
Co-60, Teletherapy, GammaKnife, HDR, Prostate Seed Implant - Correct answer-
List in order amount of activity from highest to lowest:
HDR, Co-60, Teletherapy, GammaKnife, Prostate Seed Implant
RX isodose Volume/PTV Volume - Correct answer-Conformity Index
<10% - Correct answer-Heart V25
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
,D2 - Correct answer-Maximum total dose in Gy to any point 2cm or greater away
from the PTV in any direction
V12<5-10cc - Correct answer-Brain volume SRS 1 fx
2mm; 1 degree - Correct answer-TG-142 suggests monthly QA tolerances for
lateral, longitudinal, and rotational couch positions for IMRT to be
2mm, 1% on a side - Correct answer-TG-142 suggests monthly QA tolerances for
mechanical/light field coincidence for IMRT to be
2% - Correct answer-TG-142 suggests monthly QA tolerances for electron output
constancy for IMRT to be
R50 - Correct answer-the ratio of the volume of 50% of the prescription dose
isodose to the volume of the PTV
2mm - Correct answer-TG-40 suggests daily QA tolerances for laser localization
for simulators to be
2mm - Correct answer-TG-40 suggests annual QA for medical accelerator
tolerances for gantry rotation isocenter to be
<32% - Correct answer-Kidney V20
E, FS, d, SSD - Correct answer-PDD is dependent on
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
, E, FS, d - Correct answer-TMR is dependent on
3.7 x 10^10 Bq - Correct answer-1 Ci =? Bq
10^6 - Correct answer-mega (M)
alpha particle, 1MV, 250kVp, Co-60 - Correct answer-Rank LET from highest to
lowest: 1MV, alpha particle, 250kVp, Co-60
1mSv - Correct answer-100mrad = ? dose equivalent
<12 Gy - Correct answer-Optic Nerve/Chiasm SRS 1 fx Dmax
target, Primary collimator, flattening filter, dose chambers, secondary collimator -
Correct answer-What is the correct order of components in treatment head to
generate x-rays?
6Mv - Correct answer-Which linac energy requires the highest beam current
Leukemia - Correct answer-Which is considered a stochastic effect?
Cataracts, Erythema, Sterility, Leukemia
Slightly greater - Correct answer-The lateral penumbra of a proton field is ______
as compared to a photon field.
55Gy - Correct answer-What is the ideal dose limit to 0.03cc of the brainstem?
Depth, FS, E - Correct answer-TMR are dependent on what?
©COPYRIGHT 2025, ALL RIGHTS RESERVED 4
