Helical tomotherapy to LINAC plan conversion utilizing RayStation Fallback planning

Xin Zhang; Jose Penagaricano; Ganesh Narayanasamy; Peter Corry; TianXiao Liu; Maraboyina Sanjay; Nava Paudel; Steven Morrill

doi:10.1002/acm2.12032

Helical tomotherapy to LINAC plan conversion utilizing RayStation Fallback planning

J Appl Clin Med Phys. 2017 Jan;18(1):178-185. doi: 10.1002/acm2.12032.

Authors

Xin Zhang¹, Jose Penagaricano¹, Ganesh Narayanasamy¹, Peter Corry¹, TianXiao Liu², Maraboyina Sanjay¹, Nava Paudel¹, Steven Morrill¹

Affiliations

¹ Radiation Oncology Department, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
² Radiation Oncology Department, Houston Methodist Cancer Center, Sugar Land, TX, 77479, USA.

Abstract

RaySearch RayStation Fallback (FB) planning module can generate an equivalent backup radiotherapy treatment plan facilitating treatment on other linear accelerators. FB plans were generated from the RayStation FB module by simulating the original plan target and organ at risk (OAR) dose distribution and delivered in various backup linear accelerators. In this study, helical tomotherapy (HT) backup plans used in Varian TrueBeam linear accelerator were generated with the RayStation FB module. About 30 patients, 10 with lung cancer, 10 with head and neck (HN) cancer, and 10 with prostate cancer, who were treated with HT, were included in this study. Intensity-modulated radiotherapy Fallback plans (FB-IMRT) were generated for all patients, and three-dimensional conformal radiotherapy Fallback plans (FB-3D) were only generated for lung cancer patients. Dosimetric comparison study evaluated FB plans based on dose coverage to 95% of the PTV volume (R₉₅), PTV mean dose (D_mean), Paddick's conformity index (CI), and dose homogeneity index (HI). The evaluation results showed that all IMRT plans were statistically comparable between HT and FB-IMRT plans except that PTV HI was worse in prostate, and PTV R₉₅ and HI were worse in HN multitarget plans for FB-IMRT plans. For 3D lung cancer plans, only the PTV R₉₅ was statistically comparable between HT and FB-3D plans, PTV D_mean was higher, and CI and HI were worse compared to HT plans. The FB plans using a TrueBeam linear accelerator generally offer better OAR sparing compared to HT plans for all the patients. In this study, all cases of FB-IMRT plans and 9/10 cases of FB-3D plans were clinically acceptable without further modification and optimization once the FB plans were generated. However, the statistical differences between HT and FB-IMRT/3D plans might not be of any clinically significant. One FB-3D plan failed to simulate the original plan without further optimization.

Keywords: Fallback treatment planning; RayStation; dosimetric comparison; helical tomotherapy.

MeSH terms

Head and Neck Neoplasms / diagnostic imaging
Head and Neck Neoplasms / radiotherapy*
Humans
Image Processing, Computer-Assisted / methods*
Lung Neoplasms / diagnostic imaging
Lung Neoplasms / radiotherapy*
Male
Particle Accelerators
Prostatic Neoplasms / diagnostic imaging
Prostatic Neoplasms / radiotherapy*
Radiometry
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Intensity-Modulated / methods
Tomography, Spiral Computed / methods*