Iranian Journal of Medical Physics (May 2021)
Comparison of Treatment Planning Parameters of Different Radiotherapy Techniques for Craniospinal Irradiation
Abstract
Introduction: The current study aimed 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). Material and Methods: Following a retrospective design, 22 CSI patients (Medulloblastoma) treated with Linac-3DCRT using the Novalis-Tx unit were selected for analysis. For each patient plan, additional sets of plans were 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 were 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) were evaluated for comparison. Results: The Radixact-X9-Helical technique can generate a plan in a more comparable and better manner in respect of maximum and minimum doses for most of the organs. The Radixact-X9-Helical technique resulted in better PTV homogeneity in comparison with Linac-3DCRT, Radixact-X9-Direct-3DCRT, and Radixact-X9-Direct-IMRT. The values of HI were 3.57±0.77, 17.37±1.44, 8.15±1.02, and 8.62±0.98, respectively. Conclusion: Not only administration of the Radixact-X9-Helical treatment technique is easier, but also can generate a better homogeneous plan than other treatment techniques like 3DCRT and IMRT regarding different parameters for comparisons 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, according to their clinical needs like shorter treatment time with good sparing of critical OARs.
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