The Effect of Plan Modulation on Dosimetric Effects due to Interplay in Hypofractionated Volumetric Modulated Arc Therapy Liver Radiotherapy Treatments
Abstract
When tumours that move with respiration are treated using radiation therapy techniques with dynamic beam intensity modulation, including volumetric modulated arc therapy (VMAT), the interplay between tumour motion and multileaf collimator (MLC) leaf motions may cause differences between the planned and delivered dose distributions. These interplay effects may cause underdosage in the tumour, potentially reducing treatment efficacy. This uncertainty has led to hesitation in using VMAT to treat sites impacted by respiratory motion. These differences may be greater when more MLC leaf modulation is present. To investigate the magnitude of interplay effects in a digital phantom and ten patients, a program was written to simulate respiratory motion in hypofractionated VMAT liver treatment plans with varying amounts of MLC leaf modulation. It was found that highly modulated plans were more susceptible to interplay effects, but these effects were clinically negligible in magnitude due to the hotspot present in hypofractionated treatment plans.
Description
Keywords
Physics--Radiation
Citation
Hubley, E. (2016). The Effect of Plan Modulation on Dosimetric Effects due to Interplay in Hypofractionated Volumetric Modulated Arc Therapy Liver Radiotherapy Treatments (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28089