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Kojima T, Kawamura S, Otani Y, Hanada T, Wakitani Y, Naniwa K, Yorozu A, Ikushima H, Dokiya T. Current status and issues with the dosimetric assay of iodine-125 seed sources at medical facilities in Japan: a questionnaire-based survey†. JOURNAL OF RADIATION RESEARCH 2023; 64:962-966. [PMID: 37697653 PMCID: PMC10665308 DOI: 10.1093/jrr/rrad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/13/2023] [Indexed: 09/13/2023]
Abstract
In conducting dosimetric assays of seed sources containing iodine-125 (125I), several major guidelines require the medical physicist to verify the source strength before patient treatment. Japanese guidelines do not mandate dosimetric assays at medical facilities, but since 2017, three incidents have occurred in Japan wherein seeds with incorrect strengths were delivered to medical facilities. Therefore, this study aimed to survey the current situation and any barriers to conducting the dosimetric assay of iodine-125 seeds at medical facilities in Japan. We conducted a questionnaire-based survey from December 2020 to April 2021, to examine whether seed assay and verification of the number of seeds delivered were being performed. We found that only 9 facilities (16%) performed seed assay and 28 (52%) verified the number of seeds. None of the facilities used an assay method that ensured traceability. The reasons for not performing an assay were divided into two categories: lack of resources and legal issues. Lack of resources included lack of instruments, lack of knowledge of assay methods, shorthand, or all of the above, whereas legal issues included the inability to resterilize iodine-125 seeds distributed in Japan and/or purchase seeds dedicated to the assay. Dosimetric assays, including simple methods, are effective in detecting calibration date errors and non-radioactive seeds. The study findings suggest that familiarization of medical personnel with these assay methods and investigation of the associated costs of labor and equipment should be recommended, as these measures will lead to medical reimbursement for quality assurance.
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Affiliation(s)
- Toru Kojima
- Department of Radiation Oncology, Saitama Prefectural Cancer Center, 780 Komuro, Ina-machi, Saitama 362-0806, Japan
| | - Shinji Kawamura
- Department of Radiological Technology, Graduate School of Health Sciences, Teikyo-Univercity, 6-22 Misaki-machi, Omuta, Fukuoka 836-8505, Japan
| | - Yuki Otani
- Department of Radiology, Kaizuka City Hospital, 3-10-20 Hori, Kaizuka, Osaka 597-0015, Japan
| | - Takashi Hanada
- Department of Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Yuichiro Wakitani
- Japan Radioisotope Association, 2-28-45 Hon-komagome, Bunkyo-ku, Tokyo 113-8941, Japan
| | - Kenta Naniwa
- Chiyoda Technol Corporation, 1-7-12 Yushima, Bunkyo-ku, Tokyo 113-8681, Japan
| | - Atsunori Yorozu
- Department of Radiology, National Hospital Organization Tokyo Medical Center, 2-5-1, Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan
| | - Hitoshi Ikushima
- Department of Therapeutic Radiology, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Takushi Dokiya
- The Japan Foundation for Prostate Research, 2-9-3 Higashi-Shimbashi, Minato-ku, Tokyo 105-0021, Japan
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Hasegawa T, Hanada T, Yorozu A, Ito H, Masuda S, Kawahara M, Yogo K, Hayakawa K. Microfocus X-ray imaging of the internal geometry of brachytherapy seeds. Appl Radiat Isot 2014; 86:13-20. [PMID: 24462944 DOI: 10.1016/j.apradiso.2013.12.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/26/2013] [Accepted: 12/26/2013] [Indexed: 11/28/2022]
Abstract
Precise and reliable geometrical data on the internal structure of seeds are indispensable for dosimetric calculation in brachytherapy. We used a novel microfocus X-ray imaging technique for observing the internal structure of brachytherapy seeds. Two popular (125)I seed models were evaluated. Obtained high precision images enabled us to observe the internal structure of seeds qualitatively. Geometrical size parameters were evaluated quantitatively with uncertainty of 0.01-0.04 mm (k=2).
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Affiliation(s)
- Tomoyuki Hasegawa
- School of Allied Health Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan; Graduate School of Medical Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan.
| | - Takashi Hanada
- Department of Radiology, Keio University, School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Atsunori Yorozu
- Department of Radiology, Tokyo Medical Center, National Hospital Organization, Higashigaoka 2-5-1, Meguro-ku, Tokyo 152-8902, Japan
| | - Hidetaka Ito
- Kanagawa Industrial Technology Center (KITC), Shimoimaizumi 705-1, Ebina-shi, Kanagawa 243-0435, Japan
| | - Shinji Masuda
- Kanagawa Industrial Technology Center (KITC), Shimoimaizumi 705-1, Ebina-shi, Kanagawa 243-0435, Japan
| | - Maki Kawahara
- School of Allied Health Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Katsunori Yogo
- Graduate School of Medical Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Kazushige Hayakawa
- Graduate School of Medical Sciences, Kitasato University, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan; Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Kitasato 1-15-1, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan
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