Effective clinical applications of Monte Carlo-based independent secondary dose verification software for helical tomotherapy

Takahiro Kosaka; Jun Takatsu; Tatsuya Inoue; Naoya Hara; Taira Mitsuhashi; Michimasa Suzuki; Naoto Shikama

doi:10.1016/j.ejmp.2022.11.003

Effective clinical applications of Monte Carlo-based independent secondary dose verification software for helical tomotherapy

Phys Med. 2022 Dec:104:112-122. doi: 10.1016/j.ejmp.2022.11.003. Epub 2022 Nov 15.

Authors

Takahiro Kosaka¹, Jun Takatsu², Tatsuya Inoue³, Naoya Hara⁴, Taira Mitsuhashi⁵, Michimasa Suzuki⁶, Naoto Shikama⁷

Affiliations

¹ Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan. Electronic address: t.kosaka.pa@juntendo.ac.jp.
² Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. Electronic address: j-takatsu@juntendo.ac.jp.
³ Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan; Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. Electronic address: ttinoue@juntendo.ac.jp.
⁴ Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431, Japan. Electronic address: nhara@juntendo.ac.jp.
⁵ Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan. Electronic address: t.mitsuhashi.iz@juntendo.ac.jp.
⁶ Department of Radiology, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan. Electronic address: michio@juntendo.ac.jp.
⁷ Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiation Oncology, Faculty of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Radiology, Juntendo University Hospital, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431, Japan. Electronic address: n-shikama@juntendo.ac.jp.

PMID: 36395639
DOI: 10.1016/j.ejmp.2022.11.003

Abstract

Purpose: To investigate the scope of the effective clinical application of Monte Carlo (MC)-based independent dose verification software for helical tomotherapy.

Methods: DoseCHECK was selected as the MC-based dose calculation software. First, the dose calculation accuracy of DoseCHECK was evaluated with film and chamber measurements in a water-equivalent phantom. Second, the dose calculation accuracy was examined in several heterogeneous materials. Finally, dosimetric comparisons between DoseCHECK and the treatment planning system (TPS) were performed for clinical patient plans. Prostate IMRT, head and neck IMRT (HN), total body irradiation (TBI), and brain stereotactic radiotherapy (SRT) were evaluated.

Result: The DoseCHECK calculations agreed with the chamber and film measurements in the homogenous phantom. For heterogeneous phantom cases, the dose differences between DoseCHECK and TPS were within 3 %, except in air, in which large dose differences of 20 % were observed. In clinical patient plans, the median dose differences between the lung D_mean in TBI cases and the normal brain D_mean in brain SRT cases were significantly >3 %. For HN and brain SRT cases, the median target dose differences were >3 %.

Conclusion: Our results show that independent dose verification with the MC algorithm can detect systematic errors caused by the lack of heterogeneity correction in the TPS. In particular, MC-based independent dose verification is required for HN, TBI, and brain SRT cases in helical tomotherapy.

Keywords: Helical tomotherapy; Independent secondary dose verification; Monte Carlo; Quality assurance.