CT number calibration audit in photon radiation therapy.

Autor:	Nakao M; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Department of Radiation Oncology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan., Ozawa S; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Department of Radiation Oncology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan., Miura H; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Department of Radiation Oncology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan., Yamada K; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan., Hayata M; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan., Hayashi K; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan., Kawahara D; Department of Radiation Oncology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan., Nakashima T; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Radiation Therapy Section, Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan., Ochi Y; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Radiation Therapy Section, Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan., Okumura T; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Radiation Therapy Section, Department of Clinical Support, Hiroshima University Hospital, Hiroshima, Japan., Kunimoto H; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Radiation Therapy Department, Hiroshima Prefectural Hospital, Hiroshima, Japan., Kawakubo A; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Radiation Therapy Department, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan., Kusaba H; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Radiation Therapy Department, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan., Nozaki H; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Division of Radiology, Hiroshima Red Cross Hospital & Atomic-bomb Survivors Hospital, Hiroshima, Japan., Habara K; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Division of Radiology, Hiroshima Red Cross Hospital & Atomic-bomb Survivors Hospital, Hiroshima, Japan., Tohyama N; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Division of Medical Physics, Tokyo Bay Makuhari Clinic for Advanced Imaging, Cancer Screening, and High-Precision Radiotherapy, Chiba, Japan., Nishio T; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Medical Physics Laboratory, Division of Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan., Nakamura M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Department of Radiation Oncology and Image-Applied Therapy, Kyoto University, Kyoto, Japan.; Department of Advanced Medical Physics, Graduate School of Medicine, Kyoto University, Kyoto, Japan., Minemura T; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Division of Medical Support and Partnership, Institute for Cancer Control, National Cancer Center, Tokyo, Japan., Okamoto H; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Tokyo, Japan., Ishikawa M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Faculty of Health Sciences, Hokkaido University, Hokkaido, Japan., Kurooka M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Department of Radiation Therapy, Tokyo Medical University Hospital, Tokyo, Japan., Shimizu H; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Department of Radiation Oncology, Aichi Cancer Center Hospital, Aichi, Japan., Hotta K; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Radiation Safety and Quality Assurance division, National Cancer Center Hospital East, Chiba, Japan.; Particle Therapy Division, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Chiba, Japan., Saito M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Department of Radiology, University of Yamanashi, Yamanashi, Japan., Nakano M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Department of Radiation Oncology, Kitasato University School of Medicine, Kanagawa, Japan., Tsuneda M; Medical Physics Working Group in Japan Clinical Oncology Group - Radiation Therapy Study Group, Tokyo, Japan.; Graduate School of Medicine, Chiba University, Chiba, Japan., Nagata Y; Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.; Department of Radiation Oncology, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.; Technical Support Working Group in Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, Japan.
Jazyk:	angličtina
Zdroj:	Medical physics [Med Phys] 2024 Mar; Vol. 51 (3), pp. 1571-1582. Date of Electronic Publication: 2023 Dec 19.
DOI:	10.1002/mp.16887
Abstrakt:	Background: Inadequate computed tomography (CT) number calibration curves affect dose calculation accuracy. Although CT number calibration curves registered in treatment planning systems (TPSs) should be consistent with human tissues, it is unclear whether adequate CT number calibration is performed because CT number calibration curves have not been assessed for various types of CT number calibration phantoms and TPSs. Purpose: The purpose of this study was to investigate CT number calibration curves for mass density (ρ) and relative electron density (ρ e ). Methods: A CT number calibration audit phantom was sent to 24 Japanese photon therapy institutes from the evaluating institute and scanned using their individual clinical CT scan protocols. The CT images of the audit phantom and institute-specific CT number calibration curves were submitted to the evaluating institute for analyzing the calibration curves registered in the TPSs at the participating institutes. The institute-specific CT number calibration curves were created using commercial phantom (Gammex, Gammex Inc., Middleton, WI, USA) or CIRS phantom (Computerized Imaging Reference Systems, Inc., Norfolk, VA, USA)). At the evaluating institute, theoretical CT number calibration curves were created using a stoichiometric CT number calibration method based on the CT image, and the institute-specific CT number calibration curves were compared with the theoretical calibration curve. Differences in ρ and ρ e over the multiple points on the curve (Δρ m and Δρ e,m , respectively) were calculated for each CT number, categorized for each phantom vendor and TPS, and evaluated for three tissue types: lung, soft tissues, and bones. In particular, the CT-ρ calibration curves for Tomotherapy TPSs (ACCURAY, Sunnyvale, CA, USA) were categorized separately from the Gammex CT-ρ calibration curves because the available tissue-equivalent materials (TEMs) were limited by the manufacturer recommendations. In addition, the differences in ρ and ρ e for the specific TEMs (Δρ TEM and Δρ e,TEM , respectively) were calculated by subtracting the ρ or ρ e of the TEMs from the theoretical CT-ρ or CT-ρ e calibration curve. Results: The mean ± standard deviation (SD) of Δρ m and Δρ e,m for the Gammex phantom were -1.1 ± 1.2 g/cm 3 and -0.2 ± 1.1, -0.3 ± 0.9 g/cm 3 and 0.8 ± 1.3, and -0.9 ± 1.3 g/cm 3 and 1.0 ± 1.5 for lung, soft tissues, and bones, respectively. The mean ± SD of Δρ m and Δρ e,m for the CIRS phantom were 0.3 ± 0.8 g/cm 3 and 0.9 ± 0.9, 0.6 ± 0.6 g/cm 3 and 1.4 ± 0.8, and 0.2 ± 0.5 g/cm 3 and 1.6 ± 0.5 for lung, soft tissues, and bones, respectively. The mean ± SD of Δρ m for Tomotherapy TPSs was 2.1 ± 1.4 g/cm 3 for soft tissues, which is larger than those for other TPSs. The mean ± SD of Δρ e,TEM for the Gammex brain phantom (BRN-SR2) was -1.8 ± 0.4, implying that the tissue equivalency of the BRN-SR2 plug was slightly inferior to that of other plugs. Conclusions: Latent deviations between human tissues and TEMs were found by comparing the CT number calibration curves of the various institutes. (© 2023 The Authors. Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)
Databáze:	MEDLINE
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