MDCB Practice Set 1 - Test 1
A - answer What is the approximate density of healthy lung tissue?
A. 0.30 g/cc
B. 0.95 g/cc
C. 1.00 g/cc
D. 1.03 g/cc
B - answer2. The accelerator component that injects electrons into the linear accelerator
is:
A. a klystron.
B. an electron gun.
C. a bending magnet.
D. a thyratron.
B - answer3. Radiation damage to the fetus resulting in severe birth defects would most
often occur when radiation was delivered at which time post-fertilization?
A. 0 - 2 weeks
B. 3 - 12 weeks
C. 13 - 24 weeks
D. 23 - 32 weeks
A - answer4. The decay constant for a radioactive source that has a half-life of 60 days
is:
A. 0.012.
B. 0.170.
C. 0.662.
D. 1.250.
D - answer5. The function of a maze to a megavoltage treatment room is to:
A. keep operators as remote from the machine as possible.
B. attenuate photons originating from the head of the linear accelerator.
C. separate the primary and scattered components of the beam.
D. minimize radiation levels at the door.
D - answer6. The anatomic location of the seminal vesicles is:
A. inferior to the prostate and angled anteriorly near the bladder.
B. inferior to the prostate and angled posteriorly near the rectum.
C. superior to the prostate and angled anteriorly near the bladder.
D. superior to the prostate and angled posteriorly near the rectum.
A - answer7. Two missed treatment days due to LINAC malfunction:
, A. may be compensated by adding the same or even more fractions to the treatment
course with weekend treatment if possible.
B. may allow some tumors with high growth fractions and long cell cycle times to
recover through repopulation.
C. are of major clinical relevance in most cases.
D. may be made up by increasing the fraction size for the remainder of the treatment
course.
A - answer8. For a 4-field box technique, which of the following will deliver the lowest
dose to the femoral heads?
A. 100 source-to-surface distance (SSD), equal dmax dose to all fields
B. 100 source-to-surface distance (SSD), equal target dose to all fields
C. 100 source-to-axis distance (SAD), equal air dose to all fields
D. 100 source-to-axis distance (SAD), equal target dose to all fields
A - answer9. According to the American Association of Physicists in Medicine (AAPM)
Task Group Report
#142, the constancy of dose per monitor unit for photon beams of a linear accelerator
should
be checked:
A. daily.
B. once a week.
C. once a month.
D. every three months.
D - answer10. The surface dose rate of a Strontium-90 (Sr-90) eye applicator was 4.5
cGy/second on May 15.
If a patient is to be treated 2 years later on May 15, what is the treatment time if 1000
cGy is prescribed? (The half-life of Sr-90 is 28 years.)
A. 202 seconds
B. 214 seconds
C. 222 seconds
D. 233 seconds
C - answer11. An optimized plan consists of three fields weighted 1.0 : 0.5 : 0.5 at the
isocenter. The plan was normalized to the isocenter and the radiation oncologist
prescribed 4500 cGy in 25 fractions to the 95% isodose line. What daily dose will be
delivered to the isocenter?
A. 90 : 45 : 45
B. 90 : 60 : 60
C. 95 : 47 : 47
D. 102 : 51 : 51
D - answer12. What is the approximate density of muscle?
A. 0.65 g/cc
B. 0.95 g/cc
A - answer What is the approximate density of healthy lung tissue?
A. 0.30 g/cc
B. 0.95 g/cc
C. 1.00 g/cc
D. 1.03 g/cc
B - answer2. The accelerator component that injects electrons into the linear accelerator
is:
A. a klystron.
B. an electron gun.
C. a bending magnet.
D. a thyratron.
B - answer3. Radiation damage to the fetus resulting in severe birth defects would most
often occur when radiation was delivered at which time post-fertilization?
A. 0 - 2 weeks
B. 3 - 12 weeks
C. 13 - 24 weeks
D. 23 - 32 weeks
A - answer4. The decay constant for a radioactive source that has a half-life of 60 days
is:
A. 0.012.
B. 0.170.
C. 0.662.
D. 1.250.
D - answer5. The function of a maze to a megavoltage treatment room is to:
A. keep operators as remote from the machine as possible.
B. attenuate photons originating from the head of the linear accelerator.
C. separate the primary and scattered components of the beam.
D. minimize radiation levels at the door.
D - answer6. The anatomic location of the seminal vesicles is:
A. inferior to the prostate and angled anteriorly near the bladder.
B. inferior to the prostate and angled posteriorly near the rectum.
C. superior to the prostate and angled anteriorly near the bladder.
D. superior to the prostate and angled posteriorly near the rectum.
A - answer7. Two missed treatment days due to LINAC malfunction:
, A. may be compensated by adding the same or even more fractions to the treatment
course with weekend treatment if possible.
B. may allow some tumors with high growth fractions and long cell cycle times to
recover through repopulation.
C. are of major clinical relevance in most cases.
D. may be made up by increasing the fraction size for the remainder of the treatment
course.
A - answer8. For a 4-field box technique, which of the following will deliver the lowest
dose to the femoral heads?
A. 100 source-to-surface distance (SSD), equal dmax dose to all fields
B. 100 source-to-surface distance (SSD), equal target dose to all fields
C. 100 source-to-axis distance (SAD), equal air dose to all fields
D. 100 source-to-axis distance (SAD), equal target dose to all fields
A - answer9. According to the American Association of Physicists in Medicine (AAPM)
Task Group Report
#142, the constancy of dose per monitor unit for photon beams of a linear accelerator
should
be checked:
A. daily.
B. once a week.
C. once a month.
D. every three months.
D - answer10. The surface dose rate of a Strontium-90 (Sr-90) eye applicator was 4.5
cGy/second on May 15.
If a patient is to be treated 2 years later on May 15, what is the treatment time if 1000
cGy is prescribed? (The half-life of Sr-90 is 28 years.)
A. 202 seconds
B. 214 seconds
C. 222 seconds
D. 233 seconds
C - answer11. An optimized plan consists of three fields weighted 1.0 : 0.5 : 0.5 at the
isocenter. The plan was normalized to the isocenter and the radiation oncologist
prescribed 4500 cGy in 25 fractions to the 95% isodose line. What daily dose will be
delivered to the isocenter?
A. 90 : 45 : 45
B. 90 : 60 : 60
C. 95 : 47 : 47
D. 102 : 51 : 51
D - answer12. What is the approximate density of muscle?
A. 0.65 g/cc
B. 0.95 g/cc
