Annual Report 2020
Section of Radiation Safety and Quality Assurance
Hiroyuki Okamoto, PhD (chief medical physicist), Satoshi Nakamura, PhD (medical physicist), Kotaro Iijima, MS (medical physicist), Takahito Chiba, MS (medical physicist), Junichi Kuwahara, MS (medical physicist/radiation technologist), Keita Kaga, BS (radiation technologist), Mihiro Takemori, MS, Hiroki Nakayama, MS, Yuka Urago, MS
Introduction
The role of our department is to conduct quality management for safety in radiotherapy and to establish standard procedures by implementing state-of-the-art radiation therapy in Japan. All our activities are dedicated to cancer patients; thus, we educate and develop the expertise of radiation oncologists, radiation technologists, and medical physicists. An accelerator-based boron neutron capture therapy (BNCT) system with a Li target was installed in the new facility and an epithermal neutron beam was obtained in August of 2015; the neutron facility passed the governmental inspection for radiation leakage. Non-clinical tests, such as physical and biological experiments, have been performed and a clinical trial using the system and a boron-10 compound, which is provided by STELLA PHARMA CORPORATION, has been conducted since November, 2019. The first patient was treated in November, 2019, and it was the first treatment in the world for humans using an accelerator-based BNCT system with a Li target. Additionally, an MRI-guided radiation therapy machine (MRIdian) was introduced for the first time in Japan. After strict acceptance and commissioning procedures, the MRIdian is used mainly for online adaptive radiotherapy in abdominal tumors.
The Team and What We Do
Our department is collaborating with Department of Radiation Oncology and Department of Radiological Technology, which is one of the largest radiation oncology departments in Japan. Four linear accelerators, as well as CyberKnife, MRIdian, four CT-simulators, and 15 treatment planning computers are working together via online networks to provide state-of-art precision external beam radiation therapy. In addition to the conventional X-ray and electron therapies, stereotactic irradiations of brain and body tumors and intensity-modulated radiation therapy (IMRT) are routinely performed. Stereotactic brain irradiation is performed with CyberKnife in the treatment of metastatic as well as primary brain tumors. Stereotactic body tumor irradiation is performed in lung and liver tumors by respiratory gating in linear accelerators or CyberKnife. All linear accelerators have on-board kilovoltage CT imagers, allowing us to precisely align patient and tumor coordinates. These image guided radiation therapy (IGRT) facilities enable the precise delivery of IMRT in head and neck cancers, brain tumors, prostate cancers, and postoperative cervical cancers. Fiducial markers have been implanted to improve geometric precision of radiation field reproducibility. MRIdian is used mainly for pancreatic cancer and other upper abdominal cancers in MRI-guided radiotherapy. Brachytherapy is also performed intensively to improve local control, and many patients are referred to us from all over Japan. For brachytherapy, the following modalities are being employed: an Ir-192 high-dose-rate (HDR) afterloading system including dedicated CT simulator and fluoroscopy, an I-125 seed implantation system, and other low-dose rate (LDR) brachytherapy systems using Au grains and ruthenium eye plaques. The number of patients undergoing HDR brachytherapy has continued to rise. This department is the only institution in Tokyo where HDR interstitial as well as intracavitary irradiations can be performed. HDR interstitial radiation is performed mainly on gynecological, genitourinary, and head and neck tumors. Ruthenium mold therapy is performed by ophthalmologists to treat retinoblastomas and choroidal melanomas. BNCT is also performed to treat patients with angiosarcoma or melanoma as a clinical trial. Although these tumors are rare, the efficacy of treatments are not generally excellent. We also make efforts to apply BNCT to other tumors that are resistant to conventional therapies.
Research activities
The primary interest of the research activities of the department is to establish a safe and efficient radiotherapy system. This was the final year of the National Cancer Center Research and Development Fund (30-A-14). We were able to achieve several research objectives: A postal audit for IMRT was established with the technical support for Association for Nuclear Technology in Medicine by our group. In addition, quality indicator (QI) items for medical safety in radiotherapy were determined and published. A survey study of the main domestic radiotherapy institutions was conducted. A web-based system was developed with which the institution has an opportunity to identify an insufficient QI in radiotherapy. Web seminars were held seven times to introduce the risk analysis method. Additionally, research and development (R&D) were performed for the accelerator-based BNCT system employing the Li target. As a result, the theory needed for the accelerator-based BNCT system was developed to perform BNCT safely and effectively. Furthermore, the requirements for the insurance coverage of BNCT treatment were determined by collaborating with the relevant academic societies. Given the accelerator-based BNCT system is still in the development phase in the world, the requirement specifications for an accelerator-based BNCT system were summarized at the request of the International Atomic Energy Agency (IAEA), and a submission of the first draft was then completed. These will be published as a technical document for the IAEA in the next year. Activities for establishing the international standards of the accelerator-based BNCT system were also conducted. Basic research has been conducted to ensure traceability to international standards for dosimetry as well as for conventional radiotherapy.
Clinical trials
One of our activities is to help radiation oncologists to conduct clinical trials without any problems. In addition, the credentialing process has been established in certain clinical trials by development of an independent dose assessment system.
Future Prospects
A residency program for medical physicists will begin next year. Our program features an educational environment with state-of-the-art radiotherapy and a large staff.
List of papers published in 2020
Journal
1. Kashihara T, Nakayama Y, Ito K, Kubo Y, Okuma K, Shima S, Nakamura S, Takahashi K, Inaba K, Murakami N, Igaki H, Ohe Y, Kusumoto M, Itami J. Usefulness of Simple Original Interstitial Lung Abnormality Scores for Predicting Radiation Pneumonitis Requiring Steroidal Treatment After Definitive Radiation Therapy for Patients With Locally Advanced Non-Small Cell Lung Cancer. Adv Radiat Oncol, 6:100606, 2021
2. Murakami N, Nakamura S, Kashihara T, Inaba K, Kaneda T, Takahashi K, Okuma K, Igaki H, Itami J. Increased number of prostate cancer patients selecting high dose-rate interstitial brachytherapy during the COVID-19 pandemic. Radiother Oncol, 154:274-275, 2021
3. Yogo K, Noguchi Y, Okudaira K, Nozawa M, Ishiyama H, Okamoto H, Yasuda H, Oguchi H, Yamamoto S. Source position measurement by Cherenkov emission imaging from applicators for high-dose-rate brachytherapy. Med Phys, 48:488-499, 2021
4. Su C, Okamoto H, Nishioka S, Sakasai T, Fujiyama D, Miura Y, Tsunoda Y, Kuwahara J, Nakamura S, Iijima K, Chiba T, Kaga K, Takemori M, Nakayama H, Katsuta S, Inaba K, Igaki H, Nakayama Y, Itami J. Dosimetric effect of the intestinal gas of online adaptive stereotactic body radiotherapy on target and critical organs without online electron density correction for pancreatic cancer. Br J Radiol, 94:20200239, 2021
5. Okamoto H, Kito S, Tohyama N, Yonai S, Kawamorita R, Nakamura M, Fujimoto T, Tani S, Yomoda A, Isobe T, Furukawa H, Kotaka K, Itami J, Ikushima H, Dokiya T, Shioyama Y. Radiation protection in radiological imaging: a survey of imaging modalities used in Japanese institutions for verifying applicator placements in high-dose-rate brachytherapy. J Radiat Res, 62:58-66, 2021
6. Iijima K, Murakami N, Nakamura S, Nishioka S, Chiba T, Kuwahara J, Takemori M, Nakayama H, Kashihara T, Okuma K, Takahashi K, Inaba K, Igaki H, Okamoto H, Itami J. Configuration analysis of the injection position and shape of the gel spacer in gynecologic brachytherapy. Brachytherapy, 20:95-103, 2021
7. Iijima K, Murakami N, Okamoto H, Nakamura S, Nishioka S, Chiba T, Kuwahara J, Nakayama H, Takemori M, Aikawa A, Yoshihiro S, Kashihara T, Takahashi K, Inaba K, Okuma K, Igaki H, Nakayama Y, Itami J. A dosimetric and centeredness comparison of the conventional and novel endobronchial applicators: A preliminary study. Brachytherapy, 20:467-477, 2021
8. Kashihara T, Inaba K, Komiyama M, Nakayama H, Iijima K, Nishioka S, Okamoto H, Kikkawa N, Kubo Y, Shima S, Nakamura S, Takahashi A, Takahashi K, Okuma K, Murakami N, Igaki H, Nakayama Y, Fukunaga A, Matsui Y, Fujimoto H, Itami J. The use of hyperbaric oxygen to treat actinic rectal fistula after SpaceOAR use and radiotherapy for prostate cancer: a case report. BMC Urol, 20:196, 2020
9. Murakami N, Igaki H, Okamoto H, Kashihara T, Kaneda T, Takahashi K, Inaba K, Okuma K, Itami J. Preparation for the COVID-19 pandemic in the department of radiation oncology in the National Cancer Center Hospital in Tokyo. J Radiat Res, 61:635-637, 2020
10. Karube M, Murakami N, Okamoto H, Okuma K, Kashihara T, Takahashi K, Kaneda T, Inaba K, Igaki H, Kato T, Itami J. Transvaginal artificial ascites infusion as a spacer in gynecological brachytherapy: a novel technique. J Contemp Brachytherapy, 12:487-491, 2020
11. Nishio T, Nakamura M, Okamoto H, Kito S, Minemura T, Ozawa S, Kumazaki Y, Ishikawa M, Tohyama N, Kurooka M, Nakashima T, Shimizu H, Suzuki R, Ishikura S, Nishimura Y. An overview of the medical-physics-related verification system for radiotherapy multicenter clinical trials by the Medical Physics Working Group in the Japan Clinical Oncology Group-Radiation Therapy Study Group. J Radiat Res, 61:999-1008, 2020
12. Takada M, Nunomiya T, Masuda A, Matsumoto T, Tanaka H, Nakamura S, Endo S, Nakamura M, Aoyama K, Ueda O, Narita M, Nakamura T. Characterization of a real-time neutron detector for boron neutron capture therapy using a thin silicon diode. Radiat Meas, 137:106381, 2020
13. Kajikawa T, Kadoya N, Tanaka S, Nemoto H, Takahashi N, Chiba T, Ito K, Katsuta Y, Dobashi S, Takeda K, Yamada K, Jingu K. Dose distribution correction for the influence of magnetic field using a deep convolutional neural network for online MR-guided adaptive radiotherapy. Phys Med, 80:186-192, 2020
14. Kashihara T, Kobayashi K, Iijima K, Murakami N, Yoshida K, Okuma K, Nakamura S, Takahashi K, Inaba K, Igaki H, Nakayama Y, Kato T, Uno T, Itami J. A case report of a patient with bulky uterine cervical neoplasm who achieved complete response with "intentional internal high-dose policy" high-dose-rate interstitial brachytherapy. Medicine (Baltimore), 99:e20860, 2020
15. Yoshida K, Kotsuma T, Akiyama H, Yamazaki H, Takenaka T, Masui K, Tsujimoto Y, Murakami N, Uesugi Y, Shimbo T, Yoshikawa N, Yoshioka H, Nakata M, Arika T, Takaoka Y, Tanaka E, Tselis N. A new implant device to prevent edema-associated underdosage in high-dose-rate interstitial brachytherapy of mobile tongue cancer. J Contemp Brachytherapy, 11:573-578, 2019