MDCB EXAM PREP |ACTUAL QUESTIONS AND
VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
What factors are instrumental in determining the dose uniformity in equally weighted
parallel opposed beams?
A. beam energy, tissue inhomogeneity and patient thickness
B. beam energy, patient thickness and tissue maximum ratio
C. beam flatness, patient thickness and collimator scatter
D. patient thickness, inhomogeneity and collimator scatter
CORRECT ANSWER
A. beam energy, tissue inhomogeneity and patient thickness
Question 2
Two adjacent electron fields are to be used to treat a post-mastectomy chestwall. The
radiation oncologist has expressed concern that a cold spot at the surface be avoided.
Appropriate techniques include which of the following?
A. Match the fields at the Dmax depth of the electron fields.
B. Match the fields with a 0.5 cm overlap.
C. Move the junction several times during the treatment course.
D. Match the fields with a gap of 0.5 cm at the skin surface.
CORRECT ANSWER
C. Move the junction several times during the treatment course.
Question 3
1
,Characteristics of MLC, in current medical LINACs, include which of the following:
A. accommodates all field sizes.
B. "scalloped" isodose curves in the penumbra region.
C. ability to conform to all possible field shapes.
D. inability to verify leaf shapes.
CORRECT ANSWER
B. "scalloped" isodose curves in the penumbra region.
Question 4
When treating with electrons typical X-ray contamination dose to a patient ranges from
approximately:
A. 0.1% to 0.4%
B. 0.5% to 5%
C. 6% to 9%
D. 10% to 12%
CORRECT ANSWER
B. 0.5% to 5%
Question 5
Rounded ends on the leaves of a multi-leaf collimator are used to:
A. enhance field shaping potential.
B. achieve a constant tissue-air ratio.
C. reduce interleaf leakage.
D. achieve a constant penumbra as field size varies.
CORRECT ANSWER
D. achieve a constant penumbra as field size varies.
2
,Question 6
The installation of any new treatment planning system requires the acceptance testing of
which of the following?
A. processing speed
B. software
C. power consumption
D. memory capacity
CORRECT ANSWER
B. software
Question 7
Which of the following statements is/are TRUE concerning radiation warning signs?
A. Only the term "Danger" may be used in "Radiation Areas".
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
C. Only the term "Danger" may be used in "Very High Radiation Areas".
D. Only the color scheme of magenta or purple on yellow is acceptable for use on warning
signs.
CORRECT ANSWER
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
Question 8
Based on NCRP recommendations, which of the following is a guideline regarding
pregnancy and radiation exposure?
A. The fetus can be considered as an occupationally exposed individual.
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, B. The exposure to the fetus should not exceed 50 mSv for the entire gestational period.
C. The exposure to the fetus should not exceed 5 mSv in any one month.
D. Pregnant medical radiation workers can be considered occupationally exposed individuals.
CORRECT ANSWER
D. Pregnant medical radiation workers can be considered occupationally exposed
individuals.
Question 9
When an isocentric technique is used in place of an SSD technique (both beams treated at
100SSD) to deliver the same midpoint dose to a patient with two parallel opposed fields,
the:
A. relative skin dose is decreased
B. number of monitor units for both fields is increased
C. field size at the patient's surface must be increased to treat the same volume of tissue
D. ratio of maximum dose to midpoint dose is increased
CORRECT ANSWER
D. ratio of maximum dose to midpoint dose is increased
Question 10
Computerized MU calculations for delivery of the prescribed dose to a point near a block
need special care for which of the following reasons?
A. The calculation point may be projected under the block.
B. Electron scatter from the block is not accounted by the computer.
C. The block reduces scatter in the field.
D. A steep dose gradient exists near the block.
CORRECT ANSWER
D. A steep dose gradient exists near the block.
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VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
What factors are instrumental in determining the dose uniformity in equally weighted
parallel opposed beams?
A. beam energy, tissue inhomogeneity and patient thickness
B. beam energy, patient thickness and tissue maximum ratio
C. beam flatness, patient thickness and collimator scatter
D. patient thickness, inhomogeneity and collimator scatter
CORRECT ANSWER
A. beam energy, tissue inhomogeneity and patient thickness
Question 2
Two adjacent electron fields are to be used to treat a post-mastectomy chestwall. The
radiation oncologist has expressed concern that a cold spot at the surface be avoided.
Appropriate techniques include which of the following?
A. Match the fields at the Dmax depth of the electron fields.
B. Match the fields with a 0.5 cm overlap.
C. Move the junction several times during the treatment course.
D. Match the fields with a gap of 0.5 cm at the skin surface.
CORRECT ANSWER
C. Move the junction several times during the treatment course.
Question 3
1
,Characteristics of MLC, in current medical LINACs, include which of the following:
A. accommodates all field sizes.
B. "scalloped" isodose curves in the penumbra region.
C. ability to conform to all possible field shapes.
D. inability to verify leaf shapes.
CORRECT ANSWER
B. "scalloped" isodose curves in the penumbra region.
Question 4
When treating with electrons typical X-ray contamination dose to a patient ranges from
approximately:
A. 0.1% to 0.4%
B. 0.5% to 5%
C. 6% to 9%
D. 10% to 12%
CORRECT ANSWER
B. 0.5% to 5%
Question 5
Rounded ends on the leaves of a multi-leaf collimator are used to:
A. enhance field shaping potential.
B. achieve a constant tissue-air ratio.
C. reduce interleaf leakage.
D. achieve a constant penumbra as field size varies.
CORRECT ANSWER
D. achieve a constant penumbra as field size varies.
2
,Question 6
The installation of any new treatment planning system requires the acceptance testing of
which of the following?
A. processing speed
B. software
C. power consumption
D. memory capacity
CORRECT ANSWER
B. software
Question 7
Which of the following statements is/are TRUE concerning radiation warning signs?
A. Only the term "Danger" may be used in "Radiation Areas".
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
C. Only the term "Danger" may be used in "Very High Radiation Areas".
D. Only the color scheme of magenta or purple on yellow is acceptable for use on warning
signs.
CORRECT ANSWER
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
Question 8
Based on NCRP recommendations, which of the following is a guideline regarding
pregnancy and radiation exposure?
A. The fetus can be considered as an occupationally exposed individual.
3
, B. The exposure to the fetus should not exceed 50 mSv for the entire gestational period.
C. The exposure to the fetus should not exceed 5 mSv in any one month.
D. Pregnant medical radiation workers can be considered occupationally exposed individuals.
CORRECT ANSWER
D. Pregnant medical radiation workers can be considered occupationally exposed
individuals.
Question 9
When an isocentric technique is used in place of an SSD technique (both beams treated at
100SSD) to deliver the same midpoint dose to a patient with two parallel opposed fields,
the:
A. relative skin dose is decreased
B. number of monitor units for both fields is increased
C. field size at the patient's surface must be increased to treat the same volume of tissue
D. ratio of maximum dose to midpoint dose is increased
CORRECT ANSWER
D. ratio of maximum dose to midpoint dose is increased
Question 10
Computerized MU calculations for delivery of the prescribed dose to a point near a block
need special care for which of the following reasons?
A. The calculation point may be projected under the block.
B. Electron scatter from the block is not accounted by the computer.
C. The block reduces scatter in the field.
D. A steep dose gradient exists near the block.
CORRECT ANSWER
D. A steep dose gradient exists near the block.
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