Investigation of dose homogeneity for loose helical tomotherapy delivery in the context of breath-hold radiation therapy

Abstract

Loose helical delivery is a potential solution to account for respiration-driven tumour motion in helical tomotherapy (HT). In this approach, a treatment is divided into a set of interlaced 'loose' helices commencing at different gantry angles. Each loose helix covers the entire target length in one gantry rotation during a single breath-hold. The dosimetric characteristics of loose helical delivery were investigated by delivering a 6 MV photon beam in a HT-like manner. Multiple scenarios of conventional 'tight' HT and loose helical deliveries were modelled in treatment planning software, and carried out experimentally with Kodak EDR2 film. The advantage of loose helical delivery lies in its..