MDCB: Mock Exam 2 Questions with 100%
Verified Correct Answers
A patient receiving treatment to the head and neck region has experienced a skin reaction and
mucositis at a total dose much lower than anticipated. The radiation oncologist requests an
evaluation of the treatment. Which of the following steps should be taken?
A. recalculate the treatment plan
B. ensure that the depth dose, build-up region, wedge parameters, and other pertinent information
for the treatment unit are correct
C. review the treatment setup with the therapist
D. recalculate the monitor unit settings
E. all are correct - Correct Answer E
For megavoltage dosimetry, TLD can provide accuracy of:
A. plus/minus 20%
B. plus/minus 10%
C. plus/minus 3%
D. plus/minus 1% - Correct Answer C
With megavoltage film dosimetry, isodose curves can be measured to within:
A. plus/minus 10%
B. plus/minus 7%
,C. plus/minus 3%
D. plus/minus 1% - Correct Answer C
In megavoltage therapy, typical use(s) of diodes is for:
A. patient dosimetry
B. beam scanning
C. quality assurance
D. all of the answers are correct - Correct Answer D
Which of the following is best suited for calibration of a megavoltage beam:
A. diode detector
B. thermoluminescence dosimetry
C. film
D. ionization chamber - Correct Answer D
The f-factor:
A. is the roentgen to cGy conversion factor
B. is greatest for high Z materials and low energy photons
,C. is 0.873 in air
D. all of the answers are correct
E. none of the answers are correct - Correct Answer D
Clinical application of MLC include which of the following?
A. shaping of electron fields as a replacement for cerrobend blocks
B. dynamic field shaping as a function of patient respiration
C. field shaping without penumbra
D. modulating beam intensity - Correct Answer D
The 104% isodose lines at the four corners of the target shown are due to the:
A. inhomogeneity of the femur
B. scatter from the femur
C. horns of the beams
D. weights of the lateral beams
E. use of a wrong algorithm - Correct Answer C
Exposure is:
A. the amount of energy in Joules/kg transferred from a photon beam to a material
, B. only defined for photons and charged particles below 3 MeV
C. the charge liberated by photons in a given mass of air
D. the absorbed dose multiplied by the quality factor
E. None of the answers - Correct Answer C
The quantity that an ionization chamber actually measures is:
A. roentgen
B. gray
C. charge
D. kerma
E. voltage - Correct Answer C
Geiger counters:
A. are sensitive enough to detect individual photons or particles
B. are less sensitive than ionization chambers
C. are used to calibrate linac output
D. operate on the principle of scintillation - Correct Answer A
Verified Correct Answers
A patient receiving treatment to the head and neck region has experienced a skin reaction and
mucositis at a total dose much lower than anticipated. The radiation oncologist requests an
evaluation of the treatment. Which of the following steps should be taken?
A. recalculate the treatment plan
B. ensure that the depth dose, build-up region, wedge parameters, and other pertinent information
for the treatment unit are correct
C. review the treatment setup with the therapist
D. recalculate the monitor unit settings
E. all are correct - Correct Answer E
For megavoltage dosimetry, TLD can provide accuracy of:
A. plus/minus 20%
B. plus/minus 10%
C. plus/minus 3%
D. plus/minus 1% - Correct Answer C
With megavoltage film dosimetry, isodose curves can be measured to within:
A. plus/minus 10%
B. plus/minus 7%
,C. plus/minus 3%
D. plus/minus 1% - Correct Answer C
In megavoltage therapy, typical use(s) of diodes is for:
A. patient dosimetry
B. beam scanning
C. quality assurance
D. all of the answers are correct - Correct Answer D
Which of the following is best suited for calibration of a megavoltage beam:
A. diode detector
B. thermoluminescence dosimetry
C. film
D. ionization chamber - Correct Answer D
The f-factor:
A. is the roentgen to cGy conversion factor
B. is greatest for high Z materials and low energy photons
,C. is 0.873 in air
D. all of the answers are correct
E. none of the answers are correct - Correct Answer D
Clinical application of MLC include which of the following?
A. shaping of electron fields as a replacement for cerrobend blocks
B. dynamic field shaping as a function of patient respiration
C. field shaping without penumbra
D. modulating beam intensity - Correct Answer D
The 104% isodose lines at the four corners of the target shown are due to the:
A. inhomogeneity of the femur
B. scatter from the femur
C. horns of the beams
D. weights of the lateral beams
E. use of a wrong algorithm - Correct Answer C
Exposure is:
A. the amount of energy in Joules/kg transferred from a photon beam to a material
, B. only defined for photons and charged particles below 3 MeV
C. the charge liberated by photons in a given mass of air
D. the absorbed dose multiplied by the quality factor
E. None of the answers - Correct Answer C
The quantity that an ionization chamber actually measures is:
A. roentgen
B. gray
C. charge
D. kerma
E. voltage - Correct Answer C
Geiger counters:
A. are sensitive enough to detect individual photons or particles
B. are less sensitive than ionization chambers
C. are used to calibrate linac output
D. operate on the principle of scintillation - Correct Answer A
