organ-at-risk
Also written as: OAR — organ-at-risk
Normal tissue structure that may receive significant radiation dose during cancer treatment, requiring dose limitation.
Full Definition
An organ-at-risk (OAR) is a normal tissue structure located near the target volume that may receive clinically significant radiation dose during cancer treatment. OARs require specific dose constraints to prevent treatment-related toxicity while maintaining adequate target coverage. Examples include the spinal cord, heart, lungs, kidneys, and optic nerves. Treatment planning involves carefully balancing target dose delivery with OAR dose limitations through sophisticated dose optimization algorithms. Each OAR has established dose-volume tolerances based on clinical data. Documentation of OAR doses is mandatory for treatment plan approval and quality assurance.
Usage
Usage note: Commonly abbreviated as OAR. May be plural as organs-at-risk or OARs.
In Context
- "Spinal cord dose was limited as an organ-at-risk to prevent radiation myelopathy." — Radiation treatment planning
- "All organ-at-risk constraints were met in the final treatment plan." — Plan approval documentation