Commissioning of a new total body irradiation protocol

The current planning process for adult Total Body Irradiation (TBI) using the PLATO 2D treatment planning system (TPS) at the Royal Brisbane and Women’s Hospital is cumbersome; it does not adequately simulate the treatment technique and a basic manual calculation is used to account for the effects of heterogeneities. A new treatment delivery technique is proposed; this thesis addresses the commissioning of this new regimen, including the acquisition of dosimetric data under treatment conditions to quantify the accuracy achievable by performing dose calculations using Oncentra MasterPlan TPS for this new treatment technique. Two treatment planning calculation algorithms (a pencil beam and a collapsed cone) and a total of five separate beam models (four of which were formulated specifically for TBI) were examined. Comparisons were made between calculated and measured data, which include percentage depth dose (PDD) values, profiles, an output factor, doses within homogeneous waterequivalent phantoms and doses within anthropomorphic phantoms.