TLD FOR MULTICENTRE DOSE INTERCOMPARISON IN COMPLICATED RADIOTHERAPY TREATMENTS: THE FIELD JUNCTION IN HEAD AND NECK RADIOTHERAPY

摘要

With improving technology radiotherapy treatment techniques have become increasingly complex. As such it is important to verify that different centres deliver the same dose not only under reference conditions but also in realistic patient treatment situations. The use of thermoluminescence dosimetry (TLD) was investigated for multicentre verification of treatments involving photon field abutment in head and neck treatments. Three treatment approaches were compared in eight radiotherapy centres using an anthropomorphic phantom and LiF TLD ribbons. A technique employing asymmetric collimators and a set-up that does not require patient movement between treatment fields (monoisocentric technique) was found to deliver a more homogen- ous dose more reproducibly than two more traditional techniques. Even when using the same technique the dose delivery varied significantly between different centres. This confirms the importance of verifying dose delivery in complex radiotherapy tech- niques. TLD is ideally suited for this task.