Radiation Therapy Board Review Questions
with Accurate Answers Graded A+ (2024/2025)
Prophylactic cranial irradiation for ALL is administered to a total dose of:
A. 1200 cGy
B. 1800 cGy
C. 3000 cGy
D. 4500 cGy
E. 6000 cGy - ✔️✔️B. 1800 cGy
The treatment time for a field requiring 350 monitor units while the linear acellerator
dose rate is 220 units/minute is:
A. .394 minutes
B. .629 minutes
C. 1.59 minutes
D. 2.52 minutes - ✔️✔️C. 1.59 minutes
Placing marks on the central axis only is:
A. Sufficient for daily realignment and targeting
B. Sufficient when target margins are small
C. Adequate for treating small fields
D. Insufficient for daily realignment and targeting - ✔️✔️D. Insufficient for daily
realignment and targeting
*Marks should be placed on the central axis and along coordinate planes to assure the
patient and location target is accurately reproduced.
During total CNS irradiation, the patient is:
A. Supine with an extended chin
B. Supine with chin flexed
C. Prone with chin slightly extended
D. Prone with chin flexed - ✔️✔️C. Prone with chin slightly extended
Electron contamination from high energy photon beams may result from photon
interactions with the:
A. Room air
B. Collimators
C. Bolus
,D. Lucite trays - ✔️✔️B. Collimators
Lucite is often used as the material for positioning devices. One major concern when
this material is in the path of the treatment beam is:
A. Electron contamination
B. Beam attenuation
C. Decreased rigidity
D. Acquired radioactivity - ✔️✔️B. Beam attenuation
Advantages of networked digital image management do not include:
A. Dispersed access to images
B. Multiple users can share images
C. Physical storage space is minimized
D. Computer disk space is not an issue - ✔️✔️D. Computer disk space is not an issue
In the treatment of seminoma, an external testicular shield should be used for the
remaining testicle. This is Important since the TD 5/5 for the testis is as low as:
A. 1 Gy
B. 10 Gy
C. 20 Gy
D. 40 Gy - ✔️✔️A. 1 Gy
Which of the following cannot produce a 3 dimensional image?
A. MRI
B. CT
C. Ultrasound
D. Electronic portal imaging - ✔️✔️D. Electronic portal imaging
A procedure in which an implant is made using a trocar, with radioactive sources
introduced into the trocar and then the trocar is removed is called:
A. Self-attenuation
B. Interstitial preloading
C. Intracavitary microloading
D. Interstitial afterloading - ✔️✔️D. Interstitial afterloading
The precise daily reproduction of patient position depends on:
1. Patient age
2. Type of treatment machine
3. Anatomical site treated
4. Patients overall health
,A. 1 & 2
B. 2 & 3
C. 3 & 4
D. 1 & 4 - ✔️✔️C. 3 & 4
The linear scales on the treatment table are used as an aid for:
A. Translation of patient position on the table
B. Verifying filament voltage
C. Verifying gantry readout accuracy
D. Documentation of treatment dose - ✔️✔️A. Translation of patient position on the table
Compared to water, the density of bone is:
A. 1.00
B. 1.65-1.85
C. 0.33-0.35
D. 0.2-0.26 - ✔️✔️B. 1.65-1.85
If the width of the vertebral body is 5.3 cm and measures 7.5 cm on the portal
verification film, the magnification factor is:
A. 0.706
B. 1.0
C. 1.41
D. 2.00 - ✔️✔️C. 1.41
7.5/5.3 = 1.41
A patient's treatment will be 2.54 minutes. How many seconds is this?
A. 174
B. 152.4
C. 114
D. 254.0 - ✔️✔️B. 152.4
(60/1)(x/2.54)
1x = 60(2.54)
X = 152.4
How many cobalt sources are contained in the gamma knife unit?
A. 25
, B. 105
C. 201
D. 280 - ✔️✔️C. 201
Which of the following is a nonmalignant condition treated by stereotactic radiosurgery?
A. Nasopharyngeal tumors
B. Medulloblastoma
C. Astrocytoma
D. Arteriovenous malformation - ✔️✔️D. Arteriovenous malformation
The distance between the entrance and exit points for parallel opposed fields is called
the:
A. Source to skin distance
B. Source to axis distance
C. Interfield distance
D. Source to tray distance - ✔️✔️C. Interfield distance
A lateral portal verification shows the spinal cord to be at a measured depth of 9 cm
from the skin surface. If the film magnification is 1.5, the actual depth of the cord is:
A. 4 cm
B. 6 cm
D. 9 cm
E. Not enough information - ✔️✔️B. 6 cm
9/1.5 = 6
In craniospinal irradiation, using 100 cm SSD, the spinal cord field length is 30 cm. The
skull field length is 15 cm. To align the skull field with the divergent spinal field, the
amount of collimator rotation required for the skull field is:
A. 4.3 degrees
B. 10 degrees
C. 5 degrees
D. 8.53 degrees - ✔️✔️D. 8.53 degrees
* the rotation of the collimator for the skull field is given by applying the divergence
formula:
Tan⁻¹ ((A/2)(SSD))
The divergence of the spine field is what needs to be known so the collimator angle is
parallel.
with Accurate Answers Graded A+ (2024/2025)
Prophylactic cranial irradiation for ALL is administered to a total dose of:
A. 1200 cGy
B. 1800 cGy
C. 3000 cGy
D. 4500 cGy
E. 6000 cGy - ✔️✔️B. 1800 cGy
The treatment time for a field requiring 350 monitor units while the linear acellerator
dose rate is 220 units/minute is:
A. .394 minutes
B. .629 minutes
C. 1.59 minutes
D. 2.52 minutes - ✔️✔️C. 1.59 minutes
Placing marks on the central axis only is:
A. Sufficient for daily realignment and targeting
B. Sufficient when target margins are small
C. Adequate for treating small fields
D. Insufficient for daily realignment and targeting - ✔️✔️D. Insufficient for daily
realignment and targeting
*Marks should be placed on the central axis and along coordinate planes to assure the
patient and location target is accurately reproduced.
During total CNS irradiation, the patient is:
A. Supine with an extended chin
B. Supine with chin flexed
C. Prone with chin slightly extended
D. Prone with chin flexed - ✔️✔️C. Prone with chin slightly extended
Electron contamination from high energy photon beams may result from photon
interactions with the:
A. Room air
B. Collimators
C. Bolus
,D. Lucite trays - ✔️✔️B. Collimators
Lucite is often used as the material for positioning devices. One major concern when
this material is in the path of the treatment beam is:
A. Electron contamination
B. Beam attenuation
C. Decreased rigidity
D. Acquired radioactivity - ✔️✔️B. Beam attenuation
Advantages of networked digital image management do not include:
A. Dispersed access to images
B. Multiple users can share images
C. Physical storage space is minimized
D. Computer disk space is not an issue - ✔️✔️D. Computer disk space is not an issue
In the treatment of seminoma, an external testicular shield should be used for the
remaining testicle. This is Important since the TD 5/5 for the testis is as low as:
A. 1 Gy
B. 10 Gy
C. 20 Gy
D. 40 Gy - ✔️✔️A. 1 Gy
Which of the following cannot produce a 3 dimensional image?
A. MRI
B. CT
C. Ultrasound
D. Electronic portal imaging - ✔️✔️D. Electronic portal imaging
A procedure in which an implant is made using a trocar, with radioactive sources
introduced into the trocar and then the trocar is removed is called:
A. Self-attenuation
B. Interstitial preloading
C. Intracavitary microloading
D. Interstitial afterloading - ✔️✔️D. Interstitial afterloading
The precise daily reproduction of patient position depends on:
1. Patient age
2. Type of treatment machine
3. Anatomical site treated
4. Patients overall health
,A. 1 & 2
B. 2 & 3
C. 3 & 4
D. 1 & 4 - ✔️✔️C. 3 & 4
The linear scales on the treatment table are used as an aid for:
A. Translation of patient position on the table
B. Verifying filament voltage
C. Verifying gantry readout accuracy
D. Documentation of treatment dose - ✔️✔️A. Translation of patient position on the table
Compared to water, the density of bone is:
A. 1.00
B. 1.65-1.85
C. 0.33-0.35
D. 0.2-0.26 - ✔️✔️B. 1.65-1.85
If the width of the vertebral body is 5.3 cm and measures 7.5 cm on the portal
verification film, the magnification factor is:
A. 0.706
B. 1.0
C. 1.41
D. 2.00 - ✔️✔️C. 1.41
7.5/5.3 = 1.41
A patient's treatment will be 2.54 minutes. How many seconds is this?
A. 174
B. 152.4
C. 114
D. 254.0 - ✔️✔️B. 152.4
(60/1)(x/2.54)
1x = 60(2.54)
X = 152.4
How many cobalt sources are contained in the gamma knife unit?
A. 25
, B. 105
C. 201
D. 280 - ✔️✔️C. 201
Which of the following is a nonmalignant condition treated by stereotactic radiosurgery?
A. Nasopharyngeal tumors
B. Medulloblastoma
C. Astrocytoma
D. Arteriovenous malformation - ✔️✔️D. Arteriovenous malformation
The distance between the entrance and exit points for parallel opposed fields is called
the:
A. Source to skin distance
B. Source to axis distance
C. Interfield distance
D. Source to tray distance - ✔️✔️C. Interfield distance
A lateral portal verification shows the spinal cord to be at a measured depth of 9 cm
from the skin surface. If the film magnification is 1.5, the actual depth of the cord is:
A. 4 cm
B. 6 cm
D. 9 cm
E. Not enough information - ✔️✔️B. 6 cm
9/1.5 = 6
In craniospinal irradiation, using 100 cm SSD, the spinal cord field length is 30 cm. The
skull field length is 15 cm. To align the skull field with the divergent spinal field, the
amount of collimator rotation required for the skull field is:
A. 4.3 degrees
B. 10 degrees
C. 5 degrees
D. 8.53 degrees - ✔️✔️D. 8.53 degrees
* the rotation of the collimator for the skull field is given by applying the divergence
formula:
Tan⁻¹ ((A/2)(SSD))
The divergence of the spine field is what needs to be known so the collimator angle is
parallel.
