MDCB practice questions with verified answers
A collimated field size is 10 x 10 cm2. Thirty percent of the field is
blocked. The effective field size is approximately how many cm2?
a. 5.5
b. 6.5
c. 7.5
d. 8.5 Ans✓✓✓ d. 8.5
A patient is to receive 55 Gy to a tumor in the mediastinum. In order to
meet the acceptable dose limits for the spinal cord, you could:
a. use high energy photon beams to decrease the entrance dose.
b. block the spinal cord out of all treatment fields after 40 Gy is
delivered.
c. use a BID treatment technique to achieve greater repair time for the
normal tissue cells.
d. utilize a 3DCRT beam arrangement including oblique beam angles.
Ans✓✓✓ d. utilize a 3DCRT beam arrangement including oblique beam
angles.
According to AAPM TG report #142, when performing periodic linac
quality assurance procedures, which of the following is the acceptable
tolerance for electron flatness?
a. 1%
b. 2%
,c. 3%
d. 4% Ans✓✓✓ c. 3%
According to QUANTEC guidelines, what is the percentage rate of optic
neuropathy when treating the optic nerve to a dose greater than 60 Gy
with conventional fractionation?
a. <3%
b. >3% and < 7%
c. >7% and < 20%
d. >20% and < 50% Ans✓✓✓ c. >7% and < 20%
According to QUANTEC guidelines, what rate of spinal cord myelopathy
would be expected if 70 Gy were delivered to the spinal cord with
conventional fractionation of 2 Gy per day?
A. < 5%
B. 20%
C. 50%
D. 100% Ans✓✓✓ C. 50%
According to the American Association of Physicists in Medicine (AAPM)
standards (TG40), what is the minimum time frequency for checking the
"Emergency Off" switch? (A) daily
(B) weekly
(C) monthly
, (D) quarterly Ans✓✓✓ (C) monthly
An atomic mass unit (AMU) is defined as
a. the mass of one neutron
b. the mass of one proton
c. 1/12 the mass of a carbon-12 atom
d. 1/16 the mass of an oxygen-16 atom Ans✓✓✓ c. 1/12 the mass of a
carbon-12 atom
Calculations using which algorithms have shown the most significant
gains in accuracy at interfaces of heterogeneous tissues?
a. correction based
b. pencil beam
c. convolution-superposition
d. Monte Carlo Ans✓✓✓ d. Monte Carlo
Charge capture for procedures directly related to the 3-dimensional
conformal treatment planning process covers which of the following
procedures?
a. MLC/aperture design
b. continuing/special medical physics
c. pre-treatment quality assurance
d. portal images Ans✓✓✓ a. MLC/aperture design
A collimated field size is 10 x 10 cm2. Thirty percent of the field is
blocked. The effective field size is approximately how many cm2?
a. 5.5
b. 6.5
c. 7.5
d. 8.5 Ans✓✓✓ d. 8.5
A patient is to receive 55 Gy to a tumor in the mediastinum. In order to
meet the acceptable dose limits for the spinal cord, you could:
a. use high energy photon beams to decrease the entrance dose.
b. block the spinal cord out of all treatment fields after 40 Gy is
delivered.
c. use a BID treatment technique to achieve greater repair time for the
normal tissue cells.
d. utilize a 3DCRT beam arrangement including oblique beam angles.
Ans✓✓✓ d. utilize a 3DCRT beam arrangement including oblique beam
angles.
According to AAPM TG report #142, when performing periodic linac
quality assurance procedures, which of the following is the acceptable
tolerance for electron flatness?
a. 1%
b. 2%
,c. 3%
d. 4% Ans✓✓✓ c. 3%
According to QUANTEC guidelines, what is the percentage rate of optic
neuropathy when treating the optic nerve to a dose greater than 60 Gy
with conventional fractionation?
a. <3%
b. >3% and < 7%
c. >7% and < 20%
d. >20% and < 50% Ans✓✓✓ c. >7% and < 20%
According to QUANTEC guidelines, what rate of spinal cord myelopathy
would be expected if 70 Gy were delivered to the spinal cord with
conventional fractionation of 2 Gy per day?
A. < 5%
B. 20%
C. 50%
D. 100% Ans✓✓✓ C. 50%
According to the American Association of Physicists in Medicine (AAPM)
standards (TG40), what is the minimum time frequency for checking the
"Emergency Off" switch? (A) daily
(B) weekly
(C) monthly
, (D) quarterly Ans✓✓✓ (C) monthly
An atomic mass unit (AMU) is defined as
a. the mass of one neutron
b. the mass of one proton
c. 1/12 the mass of a carbon-12 atom
d. 1/16 the mass of an oxygen-16 atom Ans✓✓✓ c. 1/12 the mass of a
carbon-12 atom
Calculations using which algorithms have shown the most significant
gains in accuracy at interfaces of heterogeneous tissues?
a. correction based
b. pencil beam
c. convolution-superposition
d. Monte Carlo Ans✓✓✓ d. Monte Carlo
Charge capture for procedures directly related to the 3-dimensional
conformal treatment planning process covers which of the following
procedures?
a. MLC/aperture design
b. continuing/special medical physics
c. pre-treatment quality assurance
d. portal images Ans✓✓✓ a. MLC/aperture design
