Four-dimensional treatment planning strategies for dynamic tumor tracking.

Introduction: Dynamic tumor tracking (DTT) is a motion management technique where the radiation beam follows a moving tumor in real time. Not modelling DTT beam motion in the treatment planning system leaves an organ at risk (OAR) vulnerable to exceeding its dose limit. This work investigates two planning strategies for DTT plans, the "Boolean OAR Method" and the "Aperture Sorting Method," to determine if they can successfully spare an OAR while maintaining sufficient target coverage.

Four-dimensional dose calculations for dynamic tumour tracking with a gimbal-mounted linear accelerator.

Purpose: In this study we present a novel method for re-calculating a treatment plan on different respiratory phases by accurately modeling the panning and tilting beam motion during DTT (the "rotation method"). This method is used to re-calculate the dose distribution of a plan on multiple breathing phases to accurately assess the dosimetry.

Methods: sIMRT plans were optimized on a breath hold computed tomography (CT) image taken at exhale (BH ) for 10 previous liver stereotactic ablative radiotherapy patients.