Independent calculation-based verification of volumetric-modulated arc therapy-stereotactic body radiotherapy plans for lung cancer.

Tomohiro Ono,Takashi Mizowaki,Takamasa Mitsuyoshi,Yusuke Tsuruta,Hiraku Iramina,Mitsuhiro Nakamura,Takashi Shintani,Yuki Miyabe,Hideaki Hirashima,Yukinori Matsuo

doi:10.1002/acm2.12900

Abstract

This study aimed to investigate the feasibility of independent calculation‐based verification of volumetric‐modulated arc therapy (VMAT)–stereotactic body radiotherapy (SBRT) for patients with lung cancer using a secondary treatment planning system (sTPS). In all, 50 patients with lung cancer who underwent VMAT‐SBRT between April 2018 and May 2019 were included in this study. VMAT‐SBRT plans were devised using the Collapsed‐Cone Convolution in RayStation (primary TPS: pTPS). DICOM files were transferred to Eclipse software (sTPS), which utilized the Eclipse software, and the dose distribution was then recalculated using Acuros XB. For the verification of dose distribution in homogeneous phantoms, the differences among pTPS, sTPS, and measurements were evaluated using passing rates of a dose difference of 5% (DD5%) and gamma index of 3%/2 mm (γ3%/2 mm). The ArcCHECK cylindrical diode array was used for measurements. For independent verification of dose‐volume parameters per the patient’s geometry, dose‐volume indices for the planning target volume (PTV) including D95% and the isocenter dose were evaluated. The mean differences (± standard deviations) between the pTPS and sTPS were then calculated. The gamma passing rates of DD5% and γ3%/2 mm criteria were 99.2 ± 2.4% and 98.6 ± 3.2% for pTPS vs. sTPS, 92.9 ± 4.0% and 94.1 ± 3.3% for pTPS vs. measurement, and 93.0 ± 4.4% and 94.3 ± 4.1% for sTPS vs. measurement, respectively. The differences between pTPS and sTPS for the PTVs of D95% and the isocenter dose were −3.1 ± 2.0% and −2.3 ± 1.8%, respectively. Our investigation of VMAT‐SBRT plans for lung cancer revealed that independent calculation‐based verification is a time‐efficient method for patient‐specific quality assurance.

Highlights

ET AL.pulmonary sites, we turned our attention to an secondary treatment planning system (sTPS) for which commercially available software is used in our facility.Stereotactic body radiotherapy (SBRT) is an effective treatment forThis study aimed to investigate the feasibility of using a commerpatients with inoperable stage I non‐small‐cell lung cancer (NSCLC).cially available software, Eclipse, as an independent calculation‐basedPrevious studies found that SBRT for NSCLC can achieve excellent verification for lung VMAT‐SBRT
Pulmonary sites, we turned our attention to an sTPS for which commercially available software is used in our facility
Patients who underwent VMAT‐SBRT were treated with the Vero4DRT system; all VMAT‐SBRT plans were created using RayStation version 6.2 (RaySearch Medical Laboratories AB, Stockholm, Sweden), which we considered the primary treatment planning system (pTPS)

Summary

Introduction

Pulmonary sites, we turned our attention to an sTPS for which commercially available software is used in our facility. Previous studies found that SBRT for NSCLC can achieve excellent verification for lung VMAT‐SBRT. 3‐year overall survival (OS) and high local control rates with minimal homogeneous phantom and patient geometry were calculated and meatoxicity.[2,3,4,5] In recent years, volumetric‐modulated arc therapy sured. Such a verification system would be more efficient for evaluating (VMAT) has been introduced as a form of SBRT for lung cancer dose distributions in pulmonary sites than computer‐based verification.

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Conclusion