MDCB CERTIFICATION SET 6 |ACTUAL QUESTIONS
AND VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
The most radiosensitive phase for mental retardation in the fetus from RT accidental
exposure is:
a) 0-7 weeks
b) 8-15 weeks
c) 16-24 weeks
d) more than 25 weeks
CORRECT ANSWER
b) 8-15 weeks
Question 2
A radioactive source is considered to be isotropic if it exhibits which of the following
characteristics?
a) Summation of the total dose is proportional to the point source.
b) Dose at depth is variable in all directions based on the placement of the source.
c) Intensity around the source is equal in all directions.
d) The total dose is a function of the size of the source calibration based on kerma rate.
CORRECT ANSWER
c) Intensity around the source is equal in all directions
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,Question 3
For which of the following malignancies has hypofractionation radiation therapy been
shown to significantly improve local control compared with standard fractionation?
a) low-grade sarcomas
b) adult high-grade gliomas
c) head and neck cancer
d) inflammatory breast cancer
CORRECT ANSWER
c) head and neck cancer
Question 4
As per the American Brachytherapy Society guidelines, the dose required to treat uveal
melanomas with Iodine-125 plaque brachytherapy is:
a) 50 Gy prescribed to 0.5 cm depth
b) 65 Gy prescribed to apex
c) 85 Gy prescribed to apex
d) 100 Gy prescribed to 0.5 cm depth
CORRECT ANSWER
c) 85 Gy prescribed to apex
Question 5
Which of the following statements is true for clinical electron beams?
a) The mean energy decreases as a quadratic function of depth.
2
, b) The maximum energy is the same as the most probable energy.
c) The surface dose is inversely proportional to the electron beam energy.
d) The most probable energy is a function of the practical range (Rp).
CORRECT ANSWER
d) The most probable energy is a function of the practical range (Rp).
Question 6
In order to avoid a 5% risk of necrosis at 5 years, what dose should the femurs not exceed?
a) 42 Gy
b) 52 Gy
c) 62 Gy
d) 72 Gy
CORRECT ANSWER
b) 52 Gy
Question 7
According to QUANTEC guidelines, the dose limit to the spinal cord using conventional
fractionation with a 0.2% rate of myelopathy is:
a) Dmax = 50 Gy including full cord cross section
b) Dmax = 45 Gy including full cord cross section
c) Dmax = 50 Gy including partial cord cross section
d) Dmax = 45 Gy including partial cord cross section
CORRECT ANSWER
a) Dmax = 50 Gy including full cord cross section
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AND VERIFIED ANSWERS|BRAND NEW 2026-2027
UPDATE|GRADED A+
Question 1
The most radiosensitive phase for mental retardation in the fetus from RT accidental
exposure is:
a) 0-7 weeks
b) 8-15 weeks
c) 16-24 weeks
d) more than 25 weeks
CORRECT ANSWER
b) 8-15 weeks
Question 2
A radioactive source is considered to be isotropic if it exhibits which of the following
characteristics?
a) Summation of the total dose is proportional to the point source.
b) Dose at depth is variable in all directions based on the placement of the source.
c) Intensity around the source is equal in all directions.
d) The total dose is a function of the size of the source calibration based on kerma rate.
CORRECT ANSWER
c) Intensity around the source is equal in all directions
1
,Question 3
For which of the following malignancies has hypofractionation radiation therapy been
shown to significantly improve local control compared with standard fractionation?
a) low-grade sarcomas
b) adult high-grade gliomas
c) head and neck cancer
d) inflammatory breast cancer
CORRECT ANSWER
c) head and neck cancer
Question 4
As per the American Brachytherapy Society guidelines, the dose required to treat uveal
melanomas with Iodine-125 plaque brachytherapy is:
a) 50 Gy prescribed to 0.5 cm depth
b) 65 Gy prescribed to apex
c) 85 Gy prescribed to apex
d) 100 Gy prescribed to 0.5 cm depth
CORRECT ANSWER
c) 85 Gy prescribed to apex
Question 5
Which of the following statements is true for clinical electron beams?
a) The mean energy decreases as a quadratic function of depth.
2
, b) The maximum energy is the same as the most probable energy.
c) The surface dose is inversely proportional to the electron beam energy.
d) The most probable energy is a function of the practical range (Rp).
CORRECT ANSWER
d) The most probable energy is a function of the practical range (Rp).
Question 6
In order to avoid a 5% risk of necrosis at 5 years, what dose should the femurs not exceed?
a) 42 Gy
b) 52 Gy
c) 62 Gy
d) 72 Gy
CORRECT ANSWER
b) 52 Gy
Question 7
According to QUANTEC guidelines, the dose limit to the spinal cord using conventional
fractionation with a 0.2% rate of myelopathy is:
a) Dmax = 50 Gy including full cord cross section
b) Dmax = 45 Gy including full cord cross section
c) Dmax = 50 Gy including partial cord cross section
d) Dmax = 45 Gy including partial cord cross section
CORRECT ANSWER
a) Dmax = 50 Gy including full cord cross section
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