Dosimetric Comparison of Integral Radiation Dose: Anisotropic Analytical Algorithm and Acuros XB in Breast Radiotherapy

Aydin Cakir,Zuleyha Akgun

doi:10.4236/ijmpcero.2019.82006

Abstract

The impact of the difference between Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) in breast radiotherapy is not clearly due to different uses and further research is required to explain this effect. The aim of this study is to investigate the contribution of calculation differences between AAA and AXB to the integral radiation dose (ID) on critical organs. Seven field intensity modulated radiotherapy (IMRT) plans were generated using with AAA and AXB algorithms for twenty patients with early stage left breast cancer after breast conserving surgery. Volumetric and dosimetric differences, as well as, the Dmean, V5, V20 doses of the left and right-sided lung, the Dmean, V10, V20, V30 doses of heart and the Dmean, V5, V10 doses of the contralateral breast were investigated. The mean dose (Dmean), V5, V20 doses of the left-sided lung, the Dmean, V5, V10 doses of right-sided lung, the Dmean, V10, V20, V30 doses of heart and the Dmean, V5, V10 doses of the contralateral breast were found to be significantly higher with AAA. In this research integral dose was also higher in the AAA recalculated plan and the AXB plan with the average dose as follows left lung 2%, heart 2%, contralateral breast 8%, contralateral lung 4% respectively. Our study revealed that the calculation differences between Acuros XB (AXB) and Anisotropic Analytical Algorithm (AAA) in breast radiotherapy caused serious differences on the stored integral doses on critical organs. In addition, AXB plans showed significantly dosimetric improvements in multiple dosimetric parameters.

Highlights

Radiotherapy contributes to reducing the risk of local recurrence after surgery in the treatment of early stage breast cancer
Our study revealed that the calculation differences between Acuros XB (AXB) and Anisotropic Analytical Algorithm (AAA) in breast radiotherapy caused serious differences on the stored integral doses on critical organs
The integral dose (ID) is the volume integral of the dose stored in a medium and it is equal to multiplication of the mean dose and volume in the medium in which the radiation is applied at any doses

Summary

Introduction

Radiotherapy contributes to reducing the risk of local recurrence after surgery in the treatment of early stage breast cancer. Because of the proximity of surrounding tissues, the chest region has a very heterogeneous structure Because of this region that contains heterogeneous tissues such as the treatment area, skin, lung, heart, and anatomical difficulties; breast radiotherapy is difficult to apply. As expected; high energy rays reduce the ID; they showed that the ID value was 1.5% - 1.7% for nasopharynx, 0.9% 1.0% and 0.3% for the pancreas, and 0.4% for the prostate. These results showed that ID reduces with increasing tumor size for similar anatomic dimensions and the ID increases with increasing size of anatomical region for similar tumor sizes [1]

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