Investigation of the Effect of Hybrid Techniques Created with Intensity Modulated Radiotherapy on the Plan Quality in Breast Cancer Radiotherapy
Sultan ÇİT1,Canan KÖKSAL AKBAŞ1,Kamuran İBİŞ2,Hatice Bilge BECERİR1
1Deparment of Health Physics, İstanbul University, Institute of Health Sciences, İstanbul-Türkiye
2Deparment of Radiation Oncology, İstanbul University Faculty of Medicine, İstanbul-Türkiye
DOI : 10.5505/tjo.2022.3819 OBJECTIVE
The aim of the study is to investigate the best radiotherapy modality in breast cancer patients regarding obtaining more conformal dose distribution while sparing the surrounding healthy tissues around the tumor using hybrid planning techniques.

The study was conducted retrospectively using computed tomography images of 20 breast cancer patients, 10 right and 10 left received radiotherapy. After preparing three-dimensional conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT) plans, IMRT based hybrid plans, named as 3DCRT+IMRT, IMRT+VMAT, and created with 50-50% dose weighted combinations for each patient using 3DCRT and VMAT. Dose volume histogram data were used to evaluate the plan quality. The comparison parameters are critical organ (OAR) doses, homogeneity index (HI), conformity index (CI), and monitor unit (MU) number.

Among the hybrid plans created with IMRT, the CI and HI values for the right and left breast irradiation were found to be the best in IMRT+VMAT hybrid plans and the doses to critical organs could be reduced using the 3DCRT+IMRT hybrid plans. At the same time, the quality of the plan increased by reducing the contralateral breast dose, irradiated breast volume, and heart dose. IMRT+3DCRT hybrid application should be considered as an option to reduce critical organ doses.

In cases that critical organ doses need to be reduced, IMRT+3DCRT hybrid technique should be considered as an alternative option. Keywords : Breast cancer; hybrid plan; radiotherapy; treatment plan comparison