Compared Evaluation for Direct Aperture Optimization (DAO) PROWESS in Intensity Modulation Radiotherapy (IMRT) Pinnacle 8.0 treatment planning

Intensity Modulated Radiation Therapy (IMRT) is a means of delivering radiation therapy where the intensity of the beam is varied within the treatment field. One of the main problems of IMRT, which becomes even more apparent as the complexity of the IMRT plan increases, is the amazing increase in the number of Monitor Units (MU) required to deliver a fractionated treatment. The difficulty with this increase in MU is its association with increased treatment times and a greater leakage of radiation from the MLCs increasing the total body dose and the risk of secondary cancers in patients. Many approaches have been taken to reduce the complexity. In this study, we used a direct aperture optimization (DAO) IMRT plan Direct aperture optimization IMRT is an IMRT method in which the aperture shapes and aperture weights are optimized simultaneously, and the MLC constraints and the number of segments are directly included in the optimization process. In DAO-IMRT planning, the planner specifies the planning objectives on the basis of the dose volume criteria for the target and critical structures as well as the number of beam segments to be delivered. The optimization only considers aperture shapes that satisfy the conditions set by the MLC. As a result, high-quality DAO-IMRT treatment plans can be generated using fewer segments (apertures) per beam. We investigated the dosimetric and technical differences in using DAO-IMRT. We also compared DAO-IMRT plans with standard beamlet-IMRT plans on phantom in terms of dosimetry, number of segments, and monitor units. In this study, we found that DAO-IMRT can achieve equal or better plans than standard beamlet-IMRT in dose optimization, secondary scattering dose and treatment time. The DAO-IMRT planning is proficient, and the plans can be delivered efficiently because small numbers of segments and monitor units are used.