Dosimetric Comparison of Total Body Irradiation and Total Marrow Irradiation Using Volumetric Arc Therapy (VMAT)

Abstract

It is aimed to compare target volume and critical organ doses using Volumeric arc therapy (VMAT) technique for Whole body irradiation (TVI) and Whole bone marrow irradiation (TKI). In the study, a random phantom with human tissue and organ densities was used.. VMAT plans were created with a daily fraction dose of 6 Gy and a total dose of 12 Gy. Target volumes and dose values received by critical organs were compared. Treatment plans The mean lung dose for VMAT-TVI is 7.6 Gy and the lens dose is 4.4 Gy, while organs at risk (OAR) doses for VMAT-TKI range from 2.7 to 7.15 Gy. In addition, pre-treatment quality control for both plans, dose accuracy between planned and administered doses using the Octavius 4D phantom, gamma index analysis with 3mm and 3% criteria in all 3 planes, we found that ≤1 for both treatment plans. We observed a very precise dose distribution between the planned and administered treatment. It was concluded that in both treatment techniques, the target volume received the desired dose, but in the VMAT-TBI technique, dose homogeneity and treatment application techniques should be improved. It was determined that other RAOs other than the lung were also better protected with TMI. As a result of our study, it was concluded that VMAT may be a suitable technique for both TBI and TMI application compared to traditional techniques in the future.