Annual Report 2023
Section of Radiation Safety and Quality Assurance
Hiroyuki Okamoto, PhD (chief medical physicist), Satoshi Nakamura, PhD (medical physicist), Kotaro Iijima, PhD (medical physicist), Takahito Chiba, Msc (medical physicist), Hiroki Nakayama, Msc (medical physicist), Yasunori Shuto, BS (radiation technologist), Yuta Kobayashi, Msc (resident medical physicist), Hironori Kishida, Msc (resident medical physicist), Yuka Urago, Msc, Masato Nishitani, Msc, Syuka Nishina, Bsc, Takumi Sakamoto, Bsc, Hana Endo, Bsc
Introduction
The role of our department is to perform quality management for safety in radiotherapy and to establish standard procedures by implementing state-of-the-art radiotherapy in Japan. All our activities are dedicated to cancer patients; thus, our mission is to educate and develop the expertise of radiation oncologists, radiation technologists, and medical physicists for safe, high precision radiotherapy. Our primary task is to comprehensively review treatment plans for preventing human error in clinical practice. In addition, our mainly task is to create treatment plans for stereotactic radiotherapy (SRT), intensity-modulated radiotherapy (IMRT), brachytherapy with collaboration to the department of radiological technology for safe radiotherapy. 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 the Department of Radiation Oncology and the Department of Radiological Technology, which are among 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-the-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 conducted using CyberKnife for treating 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 primarily used 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 employed: an Ir-192 high-dose-rate (HDR) afterloading system including a dedicated CT simulator and fluoroscopy, and ruthenium eye plaques. The number of patients undergoing HDR brachytherapy has continued to increase. 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 as a phase I clinical trial. Although these tumors are rare, the efficacy of treatments are not generally excellent. Thus, the clinical trial has been conducted to acquire the regulatory approval in the NCCH with receiving orphan device and drug designation from Ministry of Health, Labour and Welfare in Japan. We also make efforts to apply BNCT to other tumors that are resistant to conventional therapies.
Research Activities
The main research activities of our division are the development of highly advanced radiotherapy techniques, development of quality control methods, and basic research on medical safety in cooperation with the radiotherapy department from medical physics aspects. In 2023, the National Cancer Center Research and Development Fund (20220-A-18, Chief Hiroyuki Okamoto, researchers our staff) started to launch several projects, e.g., the establishment of a medical care team involving radiotherapy, introduction of a Quality Indicator (QI) for medical safety in radiotherapy, clinically implementation of risk analysis in radiotherapy, and establishment of an implementation system and guidelines for advanced radiation therapy such as BNCT and MR-guided radiation therapy. These projects must be promoted by cooperation with other organizations.
In addition, we have continued research and development (R&D) for the accelerator-based BNCT system employing the Li target to expand indications in BNCT. We also participated in a Phase II clinical trial for patients with angiosarcoma on the accelerator-based BNCT system to perform BNCT effectively and safely. As a result, the trial is proceeding without any problems.
The accelerator-based BNCT system is still in the development phase worldwide. We are investigating the required specifications for a basic accelerator-based BNCT system with the support from the Japan Agency for Medical Research Development (AMED). The results of these efforts are expected to be used to conduct the multi-center BNCT clinical trials. The activities were continued to publish the results as a guideline by 2025. We also continued the activities to establish international standards for the accelerator-based BNCT system. As a result, the international standard (International Electrotechnical Commission standard) for the accelerator-based BNCT system was performed by the Japan team in which we were participating. It was the first time for the Japan team to establish the international standard for the equipment of radiation therapy. In addition, we have been conducting basic research for establishing international standards.
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 through the development of an independent dose assessment system.
Education
We provided educational guidance to medical physicists and radiology technologists as an instructor for medical safety seminars and medical physics-related seminars at related academic societies. In addition, the medical physicist residency system was started in 2021, and medical physics-related lectures were given to medical physicist residents and new employees regardless of their position in the department. Within the radiotherapy department, radiotherapy process training was conducted for radiation technologists and medical physicists. This is a training session to confirm the entire radiotherapy process with multiple professions.
Future Prospects
In collaboration with the radiotherapy departments (the Department of Radiation Oncology and the Department of Radiological Technology), we have established a system to safely implement high-precision radiotherapy such as intensity-modulated radiotherapy, image-guided radiotherapy, stereotactic radiotherapy, respiratory gated radiotherapy, and brachytherapy. We have need to propose various measures through related academic societies with reference to our radiotherapy system. We would also like to promote the development of cutting-edge radiotherapy technologies such as MR image-guided radiotherapy and BNCT. AdditionallyIn addition, we have need to promote a medical physicist residency program with the goal of fostering developing leaders in the field of medical physics by taking advantage of the unique features of the our radiotherapy department.
List of papers published in 2023
Journal
1. Kobayashi K, Gu L, Hataya R, Mizuno T, Miyake M, Watanabe H, Takahashi M, Takamizawa Y, Yoshida Y, Nakamura S, Kouno N, Bolatkan A, Kurose Y, Harada T, Hamamoto R. Sketch-based semantic retrieval of medical images. Medical image analysis, 92:103060, 2024
2. Kishigami Y, Nakamura M, Okamoto H, Takahashi A, Iramina H, Sasaki M, Kawata K, Igaki H. Organ-contour-driven auto-matching algorithm in image-guided radiotherapy. Journal of applied clinical medical physics, 25:e14220, 2024
3. Nakahara M, Murakami N, Chiba T, Nagao A, Okuma K, Kashihara T, Kaneda T, Takahashi K, Inaba K, Nakayama Y, Kato T, Igaki H. Gynecological technical notes for appropriate spacer injections. Brachytherapy, 23:45-51, 2024
4. Nakao M, Ozawa S, Miura H, Yamada K, Hayata M, Hayashi K, Kawahara D, Nakashima T, Ochi Y, Okumura T, Kunimoto H, Kawakubo A, Kusaba H, Nozaki H, Habara K, Tohyama N, Nishio T, Nakamura M, Minemura T, Okamoto H, Ishikawa M, Kurooka M, Shimizu H, Hotta K, Saito M, Nakano M, Tsuneda M, Nagata Y. CT number calibration audit in photon radiation therapy. Medical physics, 51:1571-1582, 2024
5. Kito S, Suda Y, Tanabe S, Takizawa T, Nagahata T, Tohyama N, Okamoto H, Kodama T, Fujita Y, Miyashita H, Shinoda K, Kurooka M, Shimizu H, Ohno T, Sakamoto M. Radiological imaging protection: a study on imaging dose used while planning computed tomography for external radiotherapy in Japan. Journal of radiation research, 65:159-167, 2024
6. Okamoto H, Wakita A, Tani K, Kito S, Kurooka M, Kodama T, Tohyama N, Fujita Y, Nakamura S, Iijima K, Chiba T, Nakayama H, Murata M, Goka T, Igaki H. Plan complexity metrics for head and neck VMAT competition plans. Medical dosimetry, S0958-3947(24)00009-8, 2024
7. Nishioka S, Okamoto H, Chiba T, Kito S, Ishihara Y, Isono M, Ono T, Mizoguchi A, Mizuno N, Tohyama N, Kurooka M, Ota S, Shimizu D. Technical note: A universal worksheet for failure mode and effects analysis-A project of the Japanese College of Medical Physics. Medical physics, 51:3658-3664, 2024
8. Sakuramachi M, Murakami N, Nagao A, Kojima K, Miyata Y, Kashihara T, Kaneda T, Takahashi K, Inaba K, Okuma K, Nakayama Y, Okamoto H, Ishikawa M, Igaki H. Hydrogel spacer injection to the meso-sigmoid to protect the sigmoid colon in cervical cancer brachytherapy: A technical report. Journal of contemporary brachytherapy, 15:465-469, 2023
9. Igaki H, Nakamura S, Yamazaki N, Kaneda T, Takemori M, Kashihara T, Murakami N, Namikawa K, Nakaichi T, Okamoto H, Iijima K, Chiba T, Nakayama H, Nagao A, Sakuramachi M, Takahashi K, Inaba K, Okuma K, Nakayama Y, Shimada K, Nakagama H, Itami J. Acral cutaneous malignant melanoma treated with linear accelerator-based boron neutron capture therapy system: a case report of first patient. Frontiers in oncology, 13:1272507, 2023
10. Kashihara T, Mori T, Nakaichi T, Nakamura S, Ito K, Kurihara H, Kusumoto M, Itami J, Yoshimoto S, Igaki H. Correlation between L-amino acid transporter 1 expression and 4-borono-2-(18) F-fluoro-phenylalanine accumulation in humans. Cancer medicine, 12:20564-20572, 2023
11. Nakayama H, Okamoto H, Nakamura S, Iijima K, Chiba T, Takemori M, Nakaichi T, Mikasa S, Fujii K, Sakasai T, Kuwahara J, Miura Y, Fujiyama D, Tsunoda Y, Hanzawa T, Igaki H, Chang W. Film measurement and analytical approach for assessing treatment accuracy and latency in a magnetic resonance-guided radiotherapy system. Journal of applied clinical medical physics, 24:e13915, 2023
12. Nakamura M, Zhou D, Minemura T, Kito S, Okamoto H, Tohyama N, Kurooka M, Kumazaki Y, Ishikawa M, Clark CH, Miles E, Lehmann J, Andratschke N, Kry S, Ishikura S, Mizowaki T, Nishio T. A virtual audit system for intensity-modulated radiation therapy credentialing in Japan Clinical Oncology Group clinical trials: A pilot study. Journal of applied clinical medical physics, 24:e14040, 2023
13. Nakamura S, Imamichi S, Shimada K, Takemori M, Kanai Y, Iijima K, Chiba T, Nakayama H, Nakaichi T, Mikasa S, Urago Y, Kashihara T, Takahashi K, Nishio T, Okamoto H, Itami J, Ishiai M, Suzuki M, Igaki H, Masutani M. Relative biological effectiveness for epithermal neutron beam contaminated with fast neutrons in the linear accelerator-based boron neutron capture therapy system coupled to a solid-state lithium target. Journal of radiation research, 64:661-667, 2023
14. Murakami N, Nakatani F, Takahashi K, Nakamura S, Igaki H, Shikama N. Salvage high-dose rate brachytherapy for myxofibrosarcoma of the brachium: a technical report. Journal of radiation research, 64:746-749, 2023
15. Murakami N, Kojima K, Okuma K, Kashihara T, Nakamura S, Shimizu W, Suda R, Igaki H, Shikama N. Non-operative management involving chemoradiation therapy combined with high-dose-rate brachytherapy for T3 rectal cancer using a vaginal shielded cylindrical applicator: a technical report. Japanese journal of clinical oncology, 53:1082-1086, 2023
16. Tohyama N, Okamoto H, Shimomura K, Kurooka M, Kawamorita R, Ota S, Kojima T, Hayashi N, Okumura M, Nakamura M, Nakamura M, Myojoyama A, Onishi H. A national survey on the medical physics workload of external beam radiotherapy in Japan†. Journal of radiation research, 64:911-925, 2023
17. Nagao A, Okamoto H, Nakayama H, Chiba T, Fujiyama D, Kuwahara J, Sakasai T, Kashihara T, Kaneda T, Inaba K, Okuma K, Murakami N, Igaki H. Assessment of intrafractional motion of the cervix-uterus by MR-guided radiotherapy system†. Journal of radiation research, 64:967-972, 2023
Book
1. Okamoto H, Chiba T, Kuwahara J, Igaki H. ViewRay MR-Linac. In: Nagata Y (ed), Stereotactic Body Radiation Therapy: Principles and Practices, 2nd Edition, Springer , Singapore, pp 285-295, 2023
2. Nakamura S. Therapy method, irradiation method, and immobilization and positioning (skin). In: Shirai T, Nishio T, Sato K (ed), Advances in Accelerators and Medical Physics, Academic Press, United Kingdom, pp 251-256, 2023
3. Igaki H, Nakamura S, Nakamura M, Itami J. Accelerator-Based Neutron Irradiation System With a Lithium Target in the National Cancer Center Hospital, Japan. In: Advances in Boron Neutron Capture Therapy, International Atomic Energy Agency, Austria, pp 307-312, 2023