MDCB EXAM QUESTIONS AND ANSWERS. A+ GRADED
GUIDE.
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
A. beam energy, tissue inhomogeneity and patient thickness
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.
C. Move the junction several times during the treatment course.
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.
B. "scalloped" isodose curves in the penumbra region.
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%
B. 0.5% to 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.
D. achieve a constant penumbra as field size varies.
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
B. software
, 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.
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
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.
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.
D. Pregnant medical radiation workers can be considered occupationally exposed
individuals.
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
D. ratio of maximum dose to midpoint dose is increased
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.
D. A steep dose gradient exists near the block.
Which of the following statements is CORRECT regarding the concept of
equivalent squares in dose calculation?
A. A rectangular field is equivalent to a square field if they have the same
Area/Perimeter ratio.
B. A rectangular photon field has the same output and percentage depth dose
(PDD) as a square field of the same area.
C. Standard equivalent square table values for rectangular fields are applied to
electron output and percentage depth dose data.
D. The concept of equivalent squares is primarily useful in the determination of
beam flatness
A. A rectangular field is equivalent to a square field if they have the same
Area/Perimeter ratio.
GUIDE.
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
A. beam energy, tissue inhomogeneity and patient thickness
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.
C. Move the junction several times during the treatment course.
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.
B. "scalloped" isodose curves in the penumbra region.
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%
B. 0.5% to 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.
D. achieve a constant penumbra as field size varies.
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
B. software
, 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.
B. The terms "Caution" or "Danger" may be used in "High Radiation Areas".
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.
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.
D. Pregnant medical radiation workers can be considered occupationally exposed
individuals.
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
D. ratio of maximum dose to midpoint dose is increased
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.
D. A steep dose gradient exists near the block.
Which of the following statements is CORRECT regarding the concept of
equivalent squares in dose calculation?
A. A rectangular field is equivalent to a square field if they have the same
Area/Perimeter ratio.
B. A rectangular photon field has the same output and percentage depth dose
(PDD) as a square field of the same area.
C. Standard equivalent square table values for rectangular fields are applied to
electron output and percentage depth dose data.
D. The concept of equivalent squares is primarily useful in the determination of
beam flatness
A. A rectangular field is equivalent to a square field if they have the same
Area/Perimeter ratio.
