ABR RADIATION ONCOLOGY
CERTIFICATION EXAMINATION ACTUAL
EXAM CURRENTLY TESTING UPDATED
THIS YEAR / ALREADY GRADED A+
ABR Radiation Oncology Certification Examination —
Complete Exam Coverage
The American Board of Radiology (ABR) Radiation
Oncology Certification Examination evaluates
comprehensive competence across clinical radiation
oncology, radiation physics, radiation biology, treatment
planning, and patient management. It tests both
foundational science and advanced clinical decision-
making.
Exam coverage
Cancer staging (TNM) drives treatment intent
Radiation kills cells via DNA double-strand breaks
Fractionation exploits normal tissue repair
, IMRT improves conformity and spares OARs
Brachytherapy delivers high local dose with rapid
falloff
OAR constraints prevent late toxicity
Oxygen enhances radiation effect (OER principle)
Linear accelerator produces megavoltage photons
GTV → CTV → PTV defines treatment volumes
IGRT ensures daily setup accuracy
LQ model explains fractionation sensitivity
Acute toxicity occurs during/shortly after RT
Late toxicity is often irreversible and dose-limiting
SBRT uses high dose per fraction with precision
ALARA minimizes occupational exposure
1.
A patient with head and neck cancer has a PET-avid mass
and adjacent suspicious mucosal thickening seen only on
,MRI. The radiation oncologist is defining treatment
volumes. Which structure should include both PET-avid
disease and MRI-only suspicious extension before adding
margins?
A. PTV
B. CTV
C. ITV
D. GTV
Answer: D. GTV
Rationale:
GTV includes all visible, palpable, or radiographically
evident disease, including PET and MRI findings. CTV
comes after to include microscopic spread.
2.
A lung tumor moves 1.8 cm during respiration. A planning
system uses a single static CT. What is the most significant
risk of not accounting for this motion?
A. Increased beam energy
B. Geographic miss of tumor during part of cycle
C. Overestimation of dose to OARs
D. Improved tumor control
Answer: B
Rationale:
, Without motion modeling, part of the tumor moves
outside the high-dose region → geographic miss, especially
in SBRT.
3.
A physicist explains that at 6 MV photon energy, dose
deposition in tissue is primarily mediated by secondary
electrons. Which interaction produces these electrons most
commonly?
A. Pair production
B. Photoelectric effect
C. Compton scattering
D. Photodisintegration
Answer: C
Rationale:
At MV energies in tissue, Compton scattering dominates,
producing recoil electrons responsible for dose.
4.
A patient undergoing SBRT for liver metastasis has
irregular breathing. Which approach best reduces
interplay effect between motion and beam delivery?
CERTIFICATION EXAMINATION ACTUAL
EXAM CURRENTLY TESTING UPDATED
THIS YEAR / ALREADY GRADED A+
ABR Radiation Oncology Certification Examination —
Complete Exam Coverage
The American Board of Radiology (ABR) Radiation
Oncology Certification Examination evaluates
comprehensive competence across clinical radiation
oncology, radiation physics, radiation biology, treatment
planning, and patient management. It tests both
foundational science and advanced clinical decision-
making.
Exam coverage
Cancer staging (TNM) drives treatment intent
Radiation kills cells via DNA double-strand breaks
Fractionation exploits normal tissue repair
, IMRT improves conformity and spares OARs
Brachytherapy delivers high local dose with rapid
falloff
OAR constraints prevent late toxicity
Oxygen enhances radiation effect (OER principle)
Linear accelerator produces megavoltage photons
GTV → CTV → PTV defines treatment volumes
IGRT ensures daily setup accuracy
LQ model explains fractionation sensitivity
Acute toxicity occurs during/shortly after RT
Late toxicity is often irreversible and dose-limiting
SBRT uses high dose per fraction with precision
ALARA minimizes occupational exposure
1.
A patient with head and neck cancer has a PET-avid mass
and adjacent suspicious mucosal thickening seen only on
,MRI. The radiation oncologist is defining treatment
volumes. Which structure should include both PET-avid
disease and MRI-only suspicious extension before adding
margins?
A. PTV
B. CTV
C. ITV
D. GTV
Answer: D. GTV
Rationale:
GTV includes all visible, palpable, or radiographically
evident disease, including PET and MRI findings. CTV
comes after to include microscopic spread.
2.
A lung tumor moves 1.8 cm during respiration. A planning
system uses a single static CT. What is the most significant
risk of not accounting for this motion?
A. Increased beam energy
B. Geographic miss of tumor during part of cycle
C. Overestimation of dose to OARs
D. Improved tumor control
Answer: B
Rationale:
, Without motion modeling, part of the tumor moves
outside the high-dose region → geographic miss, especially
in SBRT.
3.
A physicist explains that at 6 MV photon energy, dose
deposition in tissue is primarily mediated by secondary
electrons. Which interaction produces these electrons most
commonly?
A. Pair production
B. Photoelectric effect
C. Compton scattering
D. Photodisintegration
Answer: C
Rationale:
At MV energies in tissue, Compton scattering dominates,
producing recoil electrons responsible for dose.
4.
A patient undergoing SBRT for liver metastasis has
irregular breathing. Which approach best reduces
interplay effect between motion and beam delivery?
