Annual Report 2023

II. Radiological Oncology

Hiroshi Tanizaki, Kanyu Ihara, Tomonori Goka, Ako Aikawa, Toshimitsu Sofue, Miyuki Murata, Yoshihiro Shibata, Yusuke Watanabe, Tatsuya Sakasai, Junichi Kuwahara, Takayuki Mori, Yusuke Miyamoto, Mitsuhiro Kon, Masato Tanaka, Yasunori Shuto, Midori Nonaka, Ayame Sugo, Kaho Miyagi, Masataka Ueda, Yusaku Kasai, Ruka Hata, Yuka Kondo, Seishi Kawamura, Natsuki Furutate, Takuma Hanzawa, Koushin Arai, Amane Hashimoto, Homare Murata, Shuichiro Kawano, Hiroko Sugaya

Introduction

 The Radiological Oncology unit in Department of Radiological Technology is home to four linear accelerators, a CyberKnife, an MRI-guided radiotherapy system (MRIdian), and image-guided brachytherapy (IGBT) systems, which we use to provide various radiotherapy treatments.

The Team and What We Do

1) Two high-precision positioning support systems (ExacTrac) were installed to further enhance the high-precision irradiation implementation system and improve treatment continuity by installing the same type of equipment side by side. Of the 2078 external irradiations, 868 were VMAT and 488 were SRT; VMAT and SRT, which are high-precision radiotherapy, are increasing every year and account for about 70% of the total number of patients.

2) The immediate adaptive radiotherapy system (MRIdian) was upgraded to a linac in July 2022. Radiotherapy was administered to 127 patients, with a total of 292 online immediate adaptive radiotherapy (Adaptive Radiation Therapy) sessions until October 2023.

3) A total of 190 cases were treated with stereotactic irradiation using a CyberKnife, consisting of 178 head-and-neck region and 12 trunk cases.

4) Total-body irradiation for bone marrow transplantation was performed in 53 cases.

5) Interstitial brachytherapy using a 106-Ru source was performed in 11 cases.

6) The high-dose-rate brachytherapy (RALS) was performed on 90 patients, with 79 intracavitary irradiation cases and 268 interstitial irradiation cases, for a total of 347 cases.

7) Phase II clinical trials for boron neutron capture therapy (BNCT) were initiated in FY2023.

8) To prevent COVID-19, we reinforced infection precautions and managed the business continuity plan.

Education

1) Personnel rotation of the radiological technologist between diagnostic technology and radiological oncology was conducted based on the educational program.

2) One of the radiological technologists belonging to the radiotherapy team was concurrently appointed to the Section of Radiation Safety and Quality Assurance to learn about radiotherapy planning and quality control.

3) Radiotherapy process training was conducted to review and improve operations.

4) The radiology technician residency program is in its second year. Two new radiology technologist residents have been hired to acquire the knowledge, skills, and attitude required of radiology technologists as well as the basic duties they must acquire in the three-year program. In addition, two senior residents have been hired to focus on specialized fields and to train and produce radiology technicians with more specialized knowledge and skills.

Future Prospects

1) Aim for the early approval of the BNCT device under the Pharmaceutical Affairs Law and the early realization of its clinical use.

2) Contribute to the spread of safe radiotherapy by improving the efficiency of quality control methods for MRIdian system and by establishing methods for training operators.

3) We will enable safe treatment and increase accurate results for RALS.

4) We will continue to cooperate with the clinical trials conducted in the Department of Radiation Oncology.

List of papers published in 2023

Journal

1. 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

2. Urikura A, Miyauchi Y, Yoshida T, Ishita Y, Takiguchi K, Aramaki T. Patient Positioning Assistive Technology Applicable to the Existing Computed Tomography System: Estimation by Pixel Value of Scout Image. Journal of computer assisted tomography, 48:110-115, 2024

3. Watanabe S, Urikura A, Ohashi K, Kitera N, Tsuchiya T, Kasai H, Kawai T, Hiwatashi A. Artifact reduction in low and ultra-low dose chest computed tomography for patients with pacemaker: A phantom study. Radiography (London, England : 1995), 30:770-775, 2024

4. 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

5. 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

6. Urikura A, Yoshida T, Matsubara K, Nomura K, Hoshino T, Takagi T. Number of computed tomography scanners and regional disparities based on population and medical resources in Japan. Radiological physics and technology, 16:355-365, 2023

7. Hirairi T, Ichikawa K, Urikura A, Kawashima H, Tabata T, Matsunami T. Improvement of diagnostic performance of hyperacute ischemic stroke in head CT using an image-based noise reduction technique with non-black-boxed process. Physica medica, 112:102646, 2023

8. Sato S, Urikura A, Mimatsu M, Miyamae Y, Jibiki Y, Yamashita M, Ishihara T. Physical characteristics of deep learning-based image processing software in computed tomography: a phantom study. Physical and engineering sciences in medicine, 46:1713-1721, 2023

9. Yoshida T, Murayama S, Yasui K, Tomida T, Urikura A. Pacemaker Malfunction During Passive Proton Beam Therapy for Localized Prostate Cancer: Case Reports and a Literature Review. Cureus, 15:e46223, 2023

10. Umemuro A, Sato M, Narita M, Hori S, Sakurai S, Nakayama T, Nakazawa A, Ogura T. Basic Study of Mammographic Image Magnification System with Eye-Detector and Simple EEG Scanner. International Scholarly and Scientific Research & Innovation, 17:101-104, 2023