RADIATION THERAPY TREATMENT PLANNING MOSBY ||
ALL SOLVED.
The depth of the 80% dose line for a clinical electron beam energy is given by _______ of the
energy. correct answers 1/3 of the energy
A volume that consists of the demonstrated tumor and any other tissue presumed to contain
tumor is called the ________ volume. correct answers target volume
What is the first objective in radiation therapy treatment planning?
A. identify routes of tumor spread and beam energy
B. define critical structures and beam angles
C. determine tumor boundaries and critical structures
D. choose beam energy and angles correct answers determine tumor boundaries and critical
structures
A tumor lethal dose is 5000 cGy. The spinal cord is adjacent to the tumor. The approximate
therapeutic ratio is: correct answers 0.9
Wedge angle refers to:
A. the angle of the actual wedge filter
B. the angle at which an isodose curve at a specific depth is tilted as a result of the wedge being
inserted in the beam
C. the angle at which an isodose curve at a specified depth is tilted with respect to the central
axis of the beam correct answers the angle at which an isodose curve at a specific depth is tilted
as a result of the wedge being inserted in the beam
The physician asks you to add a 5 x 4 corner block to a 12 x 14 open lung field. The blocked
equivalent square is: correct answers 12 x 12
,Indian club needles have:
A. gold seed
B. one hot end
C. two hot ends
D. even activity correct answers one hot end
When treating opposed oblique fields for a lung tumor:
A. SSDs for each field should be documented and verified.
B. SSDs for each field should be the same and verified.
C. Isocenter should be at the mid point of the tumor.
D. Isocenter should be at midline of the patient. correct answers A. SSDs for each field should be
documented and verified.
Bone metastasis to the thoracic spine is often managed using________treatment field(s).
A. parallel opposed
B. 90 degree hinged
C. single posterior
D. IMRT correct answers single posterior
The depth of electronic equilibrium for a 10 MV photon beam is: correct answers 2.0 cm
A dose of 4500 cGy is delivered at a depth of 10 cm where the percent depth dose is 62%. What
is the dose to an organ anterior to the target where the percent depth dose is 72%? correct
answers 5226 cGy
The closest blocked equivalent square for a 10 x 20 rectangular field with a 4 x 6 block in the
field is: correct answers 13.3
,The angle between two beams is known as the : correct answers hinge angle
If the cGy/MU is 1.0 at 100 cm SSD, what is the cGy/MU at 200 cm SSD? correct answers 0.25
cGy/MU
What thickness of cerrobend would be equivalent to 8 cm of lead? correct answers 9.6
Assuming ideal patient contour, a suitable wedge angle for two fields separated by 90 degrees
would be: correct answers 45*
Hinge Angle formula correct answers 180 - 2(wedge angle)
Wedge Angle formula correct answers 90-(hinge angle/2)
When treating the whole brain with opposing laterals, one way to minimize beam divergence into
the eye opposite the entrance port would be to: correct answers center the axis near the lateral
canthus
A magnification ring measures 5.0 cm on a simulation film. The actual size of the ring is 3.0 cm.
The ring is located 85 cm from the target. What is the target to film distance? correct answers
142cm
Magnification Formula correct answers Image size/object size
or
target to film distance/target to object distance
If the exposure rate at 1 meter is 53.7 R/minute, at what distance is the exposure rate 35
R/minute? correct answers 1.24 meters
inverse square^
, The percent depth dose is 91.8% for a 10 MV beam with a field size of 12 x 12 at 5 cm depth and
80 cm SSD. Calculate the percent depth dose for the same field size and depth for 100 cm SSD.
correct answers 92.9
What thickness of cerrobend would be equivalent to 5 cm of lead? correct answers 6
Adjacent fields with respective lengths of 40 cm and 36 cm should intersect at a depth of 10 cm.
The patient will be treated on a 100 cm isocentric accelerator using the SSD technique. Calculate
the skin gap. correct answers 3.8cm
In order to make custom Cerrobend blocks, the following information is needed:
1. target-to-film distance
2. beam energy
3. patient thickness correct answers 1. target-to-film distance
2. beam energy
The equivalent square field size must be determined in order to calculate the:
A. dose to be delivered to the central axis of an irregular field
B. relative dose values from a reference beam
C. spread of the beam from a certain distance from the target
D. air gap on the patient's external contour correct answers dose to be delivered to the central
axis of an irregular field
Hypogastric lymph nodes would likely be included in radiation field for the treatment of the:
correct answers rectum
An advantage to using custom compensators for missing tissue instead of bolus in megavoltage
therapy is:
ALL SOLVED.
The depth of the 80% dose line for a clinical electron beam energy is given by _______ of the
energy. correct answers 1/3 of the energy
A volume that consists of the demonstrated tumor and any other tissue presumed to contain
tumor is called the ________ volume. correct answers target volume
What is the first objective in radiation therapy treatment planning?
A. identify routes of tumor spread and beam energy
B. define critical structures and beam angles
C. determine tumor boundaries and critical structures
D. choose beam energy and angles correct answers determine tumor boundaries and critical
structures
A tumor lethal dose is 5000 cGy. The spinal cord is adjacent to the tumor. The approximate
therapeutic ratio is: correct answers 0.9
Wedge angle refers to:
A. the angle of the actual wedge filter
B. the angle at which an isodose curve at a specific depth is tilted as a result of the wedge being
inserted in the beam
C. the angle at which an isodose curve at a specified depth is tilted with respect to the central
axis of the beam correct answers the angle at which an isodose curve at a specific depth is tilted
as a result of the wedge being inserted in the beam
The physician asks you to add a 5 x 4 corner block to a 12 x 14 open lung field. The blocked
equivalent square is: correct answers 12 x 12
,Indian club needles have:
A. gold seed
B. one hot end
C. two hot ends
D. even activity correct answers one hot end
When treating opposed oblique fields for a lung tumor:
A. SSDs for each field should be documented and verified.
B. SSDs for each field should be the same and verified.
C. Isocenter should be at the mid point of the tumor.
D. Isocenter should be at midline of the patient. correct answers A. SSDs for each field should be
documented and verified.
Bone metastasis to the thoracic spine is often managed using________treatment field(s).
A. parallel opposed
B. 90 degree hinged
C. single posterior
D. IMRT correct answers single posterior
The depth of electronic equilibrium for a 10 MV photon beam is: correct answers 2.0 cm
A dose of 4500 cGy is delivered at a depth of 10 cm where the percent depth dose is 62%. What
is the dose to an organ anterior to the target where the percent depth dose is 72%? correct
answers 5226 cGy
The closest blocked equivalent square for a 10 x 20 rectangular field with a 4 x 6 block in the
field is: correct answers 13.3
,The angle between two beams is known as the : correct answers hinge angle
If the cGy/MU is 1.0 at 100 cm SSD, what is the cGy/MU at 200 cm SSD? correct answers 0.25
cGy/MU
What thickness of cerrobend would be equivalent to 8 cm of lead? correct answers 9.6
Assuming ideal patient contour, a suitable wedge angle for two fields separated by 90 degrees
would be: correct answers 45*
Hinge Angle formula correct answers 180 - 2(wedge angle)
Wedge Angle formula correct answers 90-(hinge angle/2)
When treating the whole brain with opposing laterals, one way to minimize beam divergence into
the eye opposite the entrance port would be to: correct answers center the axis near the lateral
canthus
A magnification ring measures 5.0 cm on a simulation film. The actual size of the ring is 3.0 cm.
The ring is located 85 cm from the target. What is the target to film distance? correct answers
142cm
Magnification Formula correct answers Image size/object size
or
target to film distance/target to object distance
If the exposure rate at 1 meter is 53.7 R/minute, at what distance is the exposure rate 35
R/minute? correct answers 1.24 meters
inverse square^
, The percent depth dose is 91.8% for a 10 MV beam with a field size of 12 x 12 at 5 cm depth and
80 cm SSD. Calculate the percent depth dose for the same field size and depth for 100 cm SSD.
correct answers 92.9
What thickness of cerrobend would be equivalent to 5 cm of lead? correct answers 6
Adjacent fields with respective lengths of 40 cm and 36 cm should intersect at a depth of 10 cm.
The patient will be treated on a 100 cm isocentric accelerator using the SSD technique. Calculate
the skin gap. correct answers 3.8cm
In order to make custom Cerrobend blocks, the following information is needed:
1. target-to-film distance
2. beam energy
3. patient thickness correct answers 1. target-to-film distance
2. beam energy
The equivalent square field size must be determined in order to calculate the:
A. dose to be delivered to the central axis of an irregular field
B. relative dose values from a reference beam
C. spread of the beam from a certain distance from the target
D. air gap on the patient's external contour correct answers dose to be delivered to the central
axis of an irregular field
Hypogastric lymph nodes would likely be included in radiation field for the treatment of the:
correct answers rectum
An advantage to using custom compensators for missing tissue instead of bolus in megavoltage
therapy is:
