ABSTRACT
Ultrasound (US) localization systems can be used in radiation therapy as a part of an image-guided radiation therapy (IGRT) program. e goal of IGRT is to pinpoint the target location at time of treatment and hence eliminate, or reduce, the risk of a geometric miss. As radiotherapy treatments become more conformal and treatment margins are reduced to allow for dose escalation, the risk of a geometric miss of the treatment target increases. is risk is especially high in sites where the target organs can move relative to the bony anatomy and traditional electronic portal image techniques, which use bony anatomy to correct for patient setup variation, do not accurately represent target location. e process of IGRT locates the so tissue target each day of treatment and allows for adjustment of patient position to correctly place the target within the radiation treatment elds.
