Comparison of Treatment Planning Parameters of Different Radiotherapy Techniques for Craniospinal Irradiation

Abstract

Aim: The purpose of this study is to compare linear accelerator-based three-dimensional conformal radiotherapy (Linac-3DCRT) technique with different techniques of the Radixact-X9 for the treatment of craniospinal irradiation (CSI).Materials and Methods: Retrospectively, twenty-two CSI patients (Medulloblastoma) which have previously planned and treated with Linac-3DCRT using Novalis-Tx unit are selected for analysis. For each patient plan, additional sets of plans are generated using Helical, Direct-3DCRT, and Direct-intensity-modulated radiotherapy (Direct-IMRT) techniques of the Radixact-X9 unit. The dose prescription for brain planning target volume (brain PTV) and spine PTV are 36 Gy in 20 fractions and kept the same for all techniques. Planning time, patient setup time, homogeneity index (HI), and different dose-volume parameters for both PTV and organs at risk (OARs) are evaluated for comparison.Results: The Radixact-X9-Helical technique plans are able to achieve the lowest possible maximum and minimum doses for most of the organs. The Radixact-X9-Helical technique gives better PTV homogeneity in comparison with Linac-3DCRT, Radixact-X9-Direct-3DCRT, and Radixact-X9-Direct-IMRT. The values of HI are 3.57±0.77, 17.37±1.44, 8.15±1.02 and 8.62±0.98 respectively.Conclusion: The Radixact-X9-Helical treatment technique is easier to use and able to generate a better homogeneous plan in comparison to other treatment techniques like 3DCRT and IMRT in respect of different parameters for comparison like dose-volume received by OARs, patient setup time, move isocenter and many more. So it can be an integral part of the radiotherapy department where patients required it, according to their clinical needs like shorter treatment time with good sparing of critical OARs.