MDCB PRACTICE TEST SET 1(1) WITH
CORRECT SOLUTIONS
What is the approximate density of healthy lung tissue? - ANSWER-0.30 g/CC
The accelerator component that injects electron into a linear accelerator is - ANSWER-a
electron gun
Radiation damage to the fetus resulting in severe birth defects would most often occurs
when radiation was delivered at which time post-fertilization? - ANSWER-3-12 weeks
The decay constant for a radioactive source that has a half life of 60 days is -
ANSWER-T1/2=(ln2)/(λ)→λ =(ln2)/(T1/2)=0.012
The function of a maze to a megavoltage treatment room is to - ANSWER-minimize
radiation levels at the door
An optimized plan consists of three fields weighted 1:.5:.5 at the isocenter. The plan
was normalized to the isocenter and the radiation oncologist prescribed 4500 cGy in 25
fractions to te 90% isodose line. What is the daily dose? - ANSWER-
4500cGY/.95=4736.7
4736.8/25=189.5
189.5/2=95
95*0.5=47
95:47:47
What is the approximate density of muscle? - ANSWER-1.03 g/cc
Which of the following is the accelerator component that supplies pulses of high power
radiofrequency microwave energy to accelerate injected electrons? - ANSWER-klystron
Two missed treatment days due to LINAC malfunction - ANSWER-may be
compensated by adding the same or even more fractions to the treatment course with
weekend treatments if possible
The anatomic location of the seminal vesicles is - ANSWER-superior to the prostate and
angles posteriorly near the rectum
For a 4-field box technique, which of the following will deliver the lowest dose to the
femoral heads? - ANSWER-100 source t o surface distance (SSD), equal dmax dose to
all fields
CORRECT SOLUTIONS
What is the approximate density of healthy lung tissue? - ANSWER-0.30 g/CC
The accelerator component that injects electron into a linear accelerator is - ANSWER-a
electron gun
Radiation damage to the fetus resulting in severe birth defects would most often occurs
when radiation was delivered at which time post-fertilization? - ANSWER-3-12 weeks
The decay constant for a radioactive source that has a half life of 60 days is -
ANSWER-T1/2=(ln2)/(λ)→λ =(ln2)/(T1/2)=0.012
The function of a maze to a megavoltage treatment room is to - ANSWER-minimize
radiation levels at the door
An optimized plan consists of three fields weighted 1:.5:.5 at the isocenter. The plan
was normalized to the isocenter and the radiation oncologist prescribed 4500 cGy in 25
fractions to te 90% isodose line. What is the daily dose? - ANSWER-
4500cGY/.95=4736.7
4736.8/25=189.5
189.5/2=95
95*0.5=47
95:47:47
What is the approximate density of muscle? - ANSWER-1.03 g/cc
Which of the following is the accelerator component that supplies pulses of high power
radiofrequency microwave energy to accelerate injected electrons? - ANSWER-klystron
Two missed treatment days due to LINAC malfunction - ANSWER-may be
compensated by adding the same or even more fractions to the treatment course with
weekend treatments if possible
The anatomic location of the seminal vesicles is - ANSWER-superior to the prostate and
angles posteriorly near the rectum
For a 4-field box technique, which of the following will deliver the lowest dose to the
femoral heads? - ANSWER-100 source t o surface distance (SSD), equal dmax dose to
all fields
