Definition: A radiation treatment margin is the area of healthy tissue around the target area that also receives radiation. Your radiation treatment margin may be the tissue around an existing tumor, or around a lumpectomy cavity. Radiation oncologists are working to find ways to keep radiation treatment margins very small, so that less healthy tissue is affected by radiation. Carefully calculated radiation treatment margins are a critical part of 3D Conformal Radiation and Intensity Modulated Radiotherapy.
Also Known As: Planning target volume margins, PTV margins, radiation margins
Examples:
During the planning for your breast radiation treatments, your oncologist will plan the best dose of radiation for your tumor or lumpectomy cavity and will allow for a radiation margin. Radiation treatment margins compensate for movements such as breathing or coughing, and cover changes in size or shape of the target area.
