intrafractional
Pronunciation: IN-tra-frak-shun-al
Motion or changes that occur within a single treatment fraction, typically referring to patient movement during radiation delivery.
Full Definition
Intrafractional motion refers to any patient movement or anatomical changes that occur during the delivery of a single radiation treatment fraction. This includes voluntary movements like breathing, involuntary physiologic motion such as cardiac movement, and gradual positional drift during treatment. Intrafractional motion is a significant concern in radiation therapy as it can lead to geographic miss of the target volume or unintended dose to critical structures. Modern techniques like real-time imaging, motion management systems, and gating are used to minimize its impact on treatment accuracy.
Usage
Usage note: Distinct from interfractional motion, which occurs between treatment sessions rather than during treatment.
In Context
- "Intrafractional monitoring revealed significant respiratory motion during the lung treatment." — Treatment delivery assessment
- "The treatment protocol included measures to minimize intrafractional patient movement." — Treatment planning directive