organs at risk
Also written as: OARs — Organs at Risk
Normal tissues whose sensitivity to radiation may significantly influence treatment planning and dose limits.
Full Definition
Organs at risk (OARs) are normal tissues that are sensitive to radiation and lie close to or within the treatment volume. These structures must be identified and contoured during treatment planning to ensure that radiation doses to them remain within acceptable tolerance limits. Common OARs include the spinal cord, optic nerves, lungs, heart, liver, kidneys, and bladder. Dose constraints for OARs are based on published literature regarding radiation tolerance and the risk of complications.
Usage
Usage note: Prefer full form in patient-facing documents; acronym acceptable in clinical notes.
In Context
- "The spinal cord was identified as the primary organ at risk for this thoracic treatment." — Treatment planning note
- "All OARs received doses below the institutional tolerance limits." — Plan evaluation report