1
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Schiefer H, Heinze S, Glatzer M. A precise and simple isodose-volume-based verification method for HDR and LDR brachytherapy plans. Brachytherapy 2023; 22:400-406. [PMID: 36635203 DOI: 10.1016/j.brachy.2022.12.007] [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: 08/30/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
PURPOSE The American Association of Physicists in Medicine (AAPM) code of practice for brachytherapy physics recommends performing an independent treatment time calculation. For this we implemented an easy to use isodose-based verification method for HDR (high-dose-rate) and LDR (low-dose-rate) brachytherapy plans. MATERIAL AND METHODS Dose-volume-based methods have been developed for Ir-192-based high-dose-rate (HDR) and I-125 prostate low-dose-rate (LDR) brachytherapy. They allow checking the integral dwell time or activity when the volume of a suitable isodose is known. The verification method was validated for 55 clinical HDR and 243 clinical LDR plans. RESULTS For HDR brachytherapy, the mean absolute difference between the estimated and calculated integral dwell time was 0.8% ± 1.0% (n = 30) with a single-source path and 2.7% ± 1.1% (n = 25) for multiple source paths. The corresponding value for LDR brachytherapy was 1.8% ± 2.0% (n = 243). In HDR brachytherapy, the verification method depends slightly on the plan class when considering one or more than one source paths. Good agreement between the estimated and calculated integral dwell times was obtained based on the 2 Gy isodose. Unlike HDR brachytherapy, the parameters used in the verification method for LDR brachytherapy plan verification strongly depend on the type of seed distribution. So, we recommend using an isodose at the prescribed dose for prostate HDR therapy. CONCLUSIONS Isodose-based verification methods are precise, do not presuppose dedicated tools, and are simple to implement in clinical practice.
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Affiliation(s)
- H Schiefer
- Department of Radiation Oncology, Kantonsspital St.Gallen, St.Gallen, Switzerland.
| | - S Heinze
- Department of Radiation Oncology, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | - M Glatzer
- Department of Radiation Oncology, Kantonsspital St.Gallen, St.Gallen, Switzerland
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2
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Watanabe Y, Maeyama T, Mizukami S, Tachibana H, Terazaki T, Takei H, Muraishi H, Gomi T, Hayashi SI. Verification of dose distribution in high dose-rate brachytherapy for cervical cancer using a normoxic N-vinylpyrrolidone polymer gel dosimeter. JOURNAL OF RADIATION RESEARCH 2022; 63:838-848. [PMID: 36109319 PMCID: PMC9726700 DOI: 10.1093/jrr/rrac053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/14/2022] [Indexed: 05/10/2023]
Abstract
The polymer gel dosimeter has been proposed for use as a 3D dosimeter for complex dose distribution measurement of high dose-rate (HDR) brachytherapy. However, various shapes of catheter/applicator for sealed radioactive source transport used in clinical cases must be placed in the gel sample. The absorbed dose readout for the magnetic resonance (MR)-based polymer gel dosimeters requires calibration data for the dose-transverse relaxation rate (R2) response. In this study, we evaluated in detail the dose uncertainty and dose resolution of three calibration methods, the multi-sample and distance methods using the Ir-192 source and the linear accelerator (linac) method using 6MV X-rays. The use of Ir-192 sources increases dose uncertainty with steep dose gradients. We clarified that the uniformly irradiated gel sample improved the signal-to-noise ratio (SNR) due to the large slice thickness of MR images and could acquire an accurate calibration curve using the linac method. The curved tandem and ovoid applicator used for intracavitary irradiation of HDR brachytherapy for cervical cancer were reproduced with a glass tube to verify the dose distribution. The results of comparison with the treatment planning system (TPS) calculation by gamma analysis on the 3%/2 mm criterion were in good agreement with a gamma pass rate of 90%. In addition, the prescription dose could be evaluated accurately. We conclude that it is easy to place catheter/applicator in the polymer gel dosimeters, making them a useful tool for verifying the 3D dose distribution of HDR brachytherapy with accurate calibration methods.
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Affiliation(s)
- Yusuke Watanabe
- Corresponding author. School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan. E-mail:
| | - Takuya Maeyama
- School of Science, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Shinya Mizukami
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hidenobu Tachibana
- Radiation Safety and Quality Assurance division, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan
| | - Tsuyoshi Terazaki
- Department of Radiology, Yokohama City Minato Red Cross Hospital, 3-12-1 Shinyamashita, Naka-ku, Yokohama, Kanagawa, 231-8682, Japan
| | - Hideyuki Takei
- Quantum Life and Medical Science Directorate, National Institute for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba, 263-8555, Japan
| | - Hiroshi Muraishi
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tsutomu Gomi
- School of Allied Health Sciences, Kitasato University, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Shin-ichiro Hayashi
- Faculty of Health Sciences, Hiroshima International University, 555-36 Kurosegakuendai, Higashihiroshima, Hiroshima, 739-2695, Japan
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3
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Tachibana H, Watanabe Y, Kurokawa S, Maeyama T, Hiroki T, Ikoma H, Hirashima H, Kojima H, Shiinoki T, Tanimoto Y, Shimizu H, Shishido H, Oka Y, Hirose TA, Kinjo M, Morozumi T, Kurooka M, Suzuki H, Saito T, Fujita K, Shirata R, Inada R, Yada R, Yamashita M, Kondo K, Hanada T, Takenaka T, Usui K, Okamoto H, Asakura H, Notake R, Kojima T, Kumazaki Y, Hatanaka S, Kikumura R, Nakajima M, Nakada R, Suzuki R, Mizuno H, Kawamura S, Nakamura M, Akimoto T. Multi-Institutional Study of End-to-End Dose Delivery Quality Assurance Testing for Image-Guided Brachytherapy Using a Gel Dosimeter. Brachytherapy 2022; 21:956-967. [PMID: 35902335 DOI: 10.1016/j.brachy.2022.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/15/2022] [Accepted: 06/19/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE To quantify dose delivery errors for high-dose-rate image-guided brachytherapy (HDR-IGBT) using an independent end-to-end dose delivery quality assurance test at multiple institutions. The novelty of our study is that this is the first multi-institutional end-to-end dose delivery study in the world. MATERIALS AND METHODS The postal audit used a polymer gel dosimeter in a cylindrical acrylic container for the afterloading system. Image acquisition using computed tomography, treatment planning, and irradiation were performed at each institution. Dose distribution comparison between the plan and gel measurement was performed. The percentage of pixels satisfying the absolute-dose gamma criterion was reviewed. RESULTS Thirty-five institutions participated in this study. The dose uncertainty was 3.6% ± 2.3% (mean ± 1.96σ). The geometric uncertainty with a coverage factor of k = 2 was 3.5 mm. The tolerance level was set to the gamma passing rate of 95% with the agreement criterion of 5% (global)/3 mm, which was determined from the uncertainty estimation. The percentage of pixels satisfying the gamma criterion was 90.4% ± 32.2% (mean ± 1.96σ). Sixty-six percent (23/35) of the institutions passed the verification. Of the institutions that failed the verification, 75% (9/12) had incorrect inputs of the offset between the catheter tip and indexer length in treatment planning and 17% (2/12) had incorrect catheter reconstruction in treatment planning. CONCLUSIONS The methodology should be useful for comprehensively checking the accuracy of HDR-IGBT dose delivery and credentialing clinical studies. The results of our study highlight the high risk of large source positional errors while delivering dose for HDR-IGBT in clinical practices.
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Affiliation(s)
- Hidenobu Tachibana
- Radiation Safety and Quality Assurance division, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
| | - Yusuke Watanabe
- School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Shogo Kurokawa
- Radiation Safety and Quality Assurance division, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Takuya Maeyama
- School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Tomoyuki Hiroki
- Department of Radiology, Tokai University Hospital, Isehara, Kanagawa, Japan
| | - Hideaki Ikoma
- Department of Radiation Technology, Ibaraki Prefectual Central Hospital, Kasama, Ibaraki, Japan
| | - Hideaki Hirashima
- Deparment of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Hironori Kojima
- Department of Radiology, Kanazawa University Hospital, Kanazawa, Ishikawa, Japan
| | - Takehiro Shiinoki
- Department of Radiation Oncology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Yuuki Tanimoto
- Department of Radiology, Shikoku Cancer Center, Matsuyama, Ehime, Japan
| | - Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan
| | - Hiroki Shishido
- Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, Sapporo, Hokkaido, Japan
| | - Yoshitaka Oka
- Department of Radiology, Fukushima Medical University Hospital, Fukushima, Fukushima, Japan
| | - Taka-Aki Hirose
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Fukuoka, Japan
| | - Masashi Kinjo
- Department of Radiology, University of the Ryukyus Graduate School of Medical Science, Nishihara, Okinawa, Japan
| | - Takuya Morozumi
- Department of Radiology, Nagano Municipal Hospital, Nagano, Nagano, Japan
| | - Masahiko Kurooka
- Department of Radiation Therapy, Tokyo Medical University Hospital, Shinjuku, Tokyo, Japan
| | - Hidekazu Suzuki
- Department of Radiology, University of Yamanashi Hospital, Chuo, Yamanashi, Japan
| | - Tomohiko Saito
- Central Division of Radiology, Akita University Hospital, Akita, Akita, Japan
| | - Keiichi Fujita
- Department of Radiology, Asahi General Hospital, Asahi, Chiba, Japan
| | - Ryosuke Shirata
- Department of Radiation Oncology, Shonan Kamakura General Hospital, Kamakura, Kanagawa, Japan
| | - Ryuji Inada
- Department of Radiology, Kitasato University Hospital, Sagamihara, Kanagawa, Japan
| | - Ryuichi Yada
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Mikiko Yamashita
- Department of Radiological Technology, Kobe City Medical Center General Hospital, Kobe, Hyogo, Japan
| | - Kazuto Kondo
- Department of Radiological Technology, Kurashiki Central Hospital, Kurashiki, Okayama, Japan
| | - Takashi Hanada
- Department of Radiology, Keio University School of Medicine, Shinjuku, Tokyo, Japan
| | - Tadashi Takenaka
- Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Kyoto, Japan
| | - Keisuke Usui
- Department of Radiological Technology, Juntendo University, Faculty of Health Science, Bunkyo, Tokyo, Japan
| | - Hiroyuki Okamoto
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo, Tokyo, Japan
| | - Hiroshi Asakura
- Radiation Oncology Center, Dokkyo Medical University Hospital, Shimotsuga, Tochigi, Japan
| | - Ryoichi Notake
- Department of Radiology, Tokyo Medical And Dental University, Medical Hospital, Bunkyo, Tokyo, Japan
| | - Toru Kojima
- Department of Radiation Oncology, Saitama Cancer Center, Ina, Saitama, Japan
| | - Yu Kumazaki
- Department of Radiation Oncology, Saitama Medical University International Medical Center, Hidaka, Saitama, Japan
| | - Shogo Hatanaka
- Department of Radiation Oncology, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Riki Kikumura
- Department of Radiology, National Hospital Organization, Tokyo Medical Center, Meguro, Tokyo, Japan
| | - Masaru Nakajima
- Department of Radiation Oncology, The Cancer Institute Hospital Of JFCR, Koto, Tokyo, Japan
| | - Ryosei Nakada
- Radiation and Proton Therapy Center, Shizuoka Cancer Center, Nagaizumi, Shizuoka, Japan
| | - Ryusuke Suzuki
- Department of Medical physics, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Hideyuki Mizuno
- Quality control section, QST hospital, National Institutes for Quantum Science and Technology, Chiba, Chiba, Japan
| | - Shinji Kawamura
- Division of Radiological Sciences, Teikyo University Graduate School of Health Sciences, Omuta, Fukuoka, Japan
| | - Mistuhiro Nakamura
- Division of Medical Physics, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Tetsuo Akimoto
- Department of Radiation Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
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De Deene Y. Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D. Gels 2022; 8:599. [PMID: 36135311 PMCID: PMC9498652 DOI: 10.3390/gels8090599] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/07/2022] [Accepted: 09/10/2022] [Indexed: 12/22/2022] Open
Abstract
Gel dosimetry was developed in the 1990s in response to a growing need for methods to validate the radiation dose distribution delivered to cancer patients receiving high-precision radiotherapy. Three different classes of gel dosimeters were developed and extensively studied. The first class of gel dosimeters is the Fricke gel dosimeters, which consist of a hydrogel with dissolved ferrous ions that oxidize upon exposure to ionizing radiation. The oxidation results in a change in the nuclear magnetic resonance (NMR) relaxation, which makes it possible to read out Fricke gel dosimeters by use of quantitative magnetic resonance imaging (MRI). The radiation-induced oxidation in Fricke gel dosimeters can also be visualized by adding an indicator such as xylenol orange. The second class of gel dosimeters is the radiochromic gel dosimeters, which also exhibit a color change upon irradiation but do not use a metal ion. These radiochromic gel dosimeters do not demonstrate a significant radiation-induced change in NMR properties. The third class is the polymer gel dosimeters, which contain vinyl monomers that polymerize upon irradiation. Polymer gel dosimeters are predominantly read out by quantitative MRI or X-ray CT. The accuracy of the dosimeters depends on both the physico-chemical properties of the gel dosimeters and on the readout technique. Many different gel formulations have been proposed and discussed in the scientific literature in the last three decades, and scanning methods have been optimized to achieve an acceptable accuracy for clinical dosimetry. More recently, with the introduction of the MR-Linac, which combines an MRI-scanner and a clinical linear accelerator in one, it was shown possible to acquire dose maps during radiation, but new challenges arise.
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Affiliation(s)
- Yves De Deene
- Liverpool & Macarthur Cancer Therapy Centres, Liverpool, NSW 1871, Australia; or
- Ingham Institute, Liverpool, NSW 2170, Australia
- School of Science, Western Sydney University, Penrith, NSW 2751, Australia
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5
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Rabaeh KA, Hammoudeh IME, Eyadeh MM. Novel polymer gel dosimeters based on N-Vinylcaprolactam for medical dosimetry. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08361-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Improved Dose Response of N-(Hydroxymethyl)acrylamide Gel Dosimeter with Calcium Chloride for Radiotherapy. Gels 2022; 8:gels8020078. [PMID: 35200459 PMCID: PMC8871509 DOI: 10.3390/gels8020078] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/08/2022] [Accepted: 01/21/2022] [Indexed: 12/10/2022] Open
Abstract
The impact of calcium chloride (CaCl2) on the performance of N-(hydroxymethyl)acrylamide (NHMA) polymer gel dosimeter is studied in this article. The dosimeter was exposed to doses of up to 10 Gy with radiation beam-energy of 10 MV and dose-rates of 300 cGy/min. The relaxation rate (R2) parameter was utilized to explore the performance of irradiated NHMAGAT gels. The dose response in terms of R2 increased from 0.29 to 0.63 Gy−1·s−1 with increasing calcium chloride concentration from 0 to 1000 mM. The results show no substantial impact of dose-rates as well as radiation energies on NHMAGAT samples. For the steadiness of irradiated NHMAGAT dosimeters, it was found that there is no apparent variation in R2 (less than ±3%; standard deviation) up to 3 days. The overall uncertainty of the gel dosimeter with calcium chloride is 4.96% (double standard deviation, 95% confidence level).
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7
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Ota J, Yokota H, Kobayashi T, Ogata Y, Kubo T, Chida K, Masuda Y, Uno T. Head CT dose reduction with organ-based tube current modulation. Med Phys 2022; 49:1964-1971. [PMID: 35060639 DOI: 10.1002/mp.15467] [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: 02/16/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND A helical head CT examination uses a pitch factor (PF) of < 1.0, resulting in a part of the slice being directly irradiated twice. This raises the possibility of double irradiation, which may increase the amount of radiation to the lens. Organ-based tube current modulation (OBTCM) is an effective method for reducing lens exposure because it reduces the dose to the anterior aspect of the patient. However, it is challenging to visualize the complex dose distribution when factoring in double irradiation. PURPOSE To visualize twice-irradiated areas in helical head CT in three dimensions and to clarify the exposure reduction effect of OBTCM. MATERIAL AND METHODS A leuco crystal violet (LCV) dosimeter was placed into an empty polyethylene terephthalate bottle 16.5 cm in diameter. Helical scans were performed without and with OBTCM using the following parameters: tube voltage 120 kV, tube current 600 mA, pitch factor 0.637, rotation time 0.5 s, 80 (detector rows) × 0.5 mm (detector collimation), and ten scans. Exposed areas were visualized using an optical computed tomography (OCT) system designed by our group. The dose reduction rate of OBTCM was defined as the ratio of the average values of the histogram with the dose value on the x-axis and the frequency on the y-axis without and with OBTCM at 90° to the anterior midline. RESULTS The LCV dosimeter visualized the spiral-shaped twice-irradiated areas. Double irradiation resulted in a dose of 2.19/1.90 Gy and 1.38/1.19 Gy (15.0% and 15.9% increase) without and with OBTCM, respectively. The dose reduction using OBTCM was 29.6% at 90° anterolateral. CONCLUSION The LCV dosimeter visualized the complex three-dimensional irradiated areas and enabled dose measurement in twice-irradiated areas. Increased exposure from double irradiation was attenuated by OBTCM. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Joji Ota
- Department of Radiology, Chiba University Hospital, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba, 260-8677, Japan.,School of Radiological Technology, Health Sciences, Graduate School of Medicine, Tohoku University, 2-1 Seiryo, Aoba, Sendai, Miyagi, Japan
| | - Hajime Yokota
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan
| | - Takenori Kobayashi
- Division of Clinical Radiology, Graduate School of Medical Care and Technology, Teikyo University, 2-11-1 Kaga Itabashi-ku, Tokyo, Japan
| | - Yuki Ogata
- Division of Clinical Radiology, Graduate School of Medical Care and Technology, Teikyo University, 2-11-1 Kaga Itabashi-ku, Tokyo, Japan
| | - Takumi Kubo
- Division of Clinical Radiology, Graduate School of Medical Care and Technology, Teikyo University, 2-11-1 Kaga Itabashi-ku, Tokyo, Japan
| | - Koichi Chida
- School of Radiological Technology, Health Sciences, Graduate School of Medicine, Tohoku University, 2-1 Seiryo, Aoba, Sendai, Miyagi, Japan
| | - Yoshitada Masuda
- Department of Radiology, Chiba University Hospital, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba, 260-8677, Japan
| | - Takashi Uno
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan
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8
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Mizukami S, Watanabe Y, Mizoguchi T, Gomi T, Hara H, Takei H, Fukunishi N, Ishikawa KL, Fukuda S, Maeyama T. Whole Three-Dimensional Dosimetry of Carbon Ion Beams with an MRI-Based Nanocomposite Fricke Gel Dosimeter Using Rapid T1 Mapping Method. Gels 2021; 7:233. [PMID: 34940293 PMCID: PMC8701283 DOI: 10.3390/gels7040233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 11/17/2022] Open
Abstract
MRI-based gel dosimeters are attractive systems for the evaluation of complex dose distributions in radiotherapy. In particular, the nanocomposite Fricke gel dosimeter is one among a few dosimeters capable of accurately evaluating the dose distribution of heavy ion beams. In contrast, reduction of the scanning time is a challenging issue for the acquisition of three-dimensional volume data. In this study, we investigated a three-dimensional dose distribution measurement method for heavy ion beams using variable flip angle (VFA), which is expected to significantly reduce the MRI scanning time. Our findings clarified that the whole three-dimensional dose distribution could be evaluated within the conventional imaging time (20 min) and quality of one cross-section.
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Affiliation(s)
- Shinya Mizukami
- School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan; (S.M.); (Y.W.); (T.G.); (H.H.)
| | - Yusuke Watanabe
- School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan; (S.M.); (Y.W.); (T.G.); (H.H.)
| | - Takahiro Mizoguchi
- Graduate School of Medical Sciences, Kitasato University, Sagamihara 252-0373, Japan;
| | - Tsutomu Gomi
- School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan; (S.M.); (Y.W.); (T.G.); (H.H.)
| | - Hidetake Hara
- School of Allied Health Sciences, Kitasato University, Sagamihara 252-0373, Japan; (S.M.); (Y.W.); (T.G.); (H.H.)
| | - Hideyuki Takei
- Proton Medical Research Center, University of Tsukuba Hospital, Tsukuba 305-8576, Japan;
| | - Nobuhisa Fukunishi
- Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198, Japan;
| | - Kenichi L. Ishikawa
- Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan;
| | - Shigekazu Fukuda
- QST Hospital, National Institutes for Quantum Science and Technology, Chiba 263-8555, Japan;
| | - Takuya Maeyama
- Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198, Japan;
- Department of Chemistry, School of Science, Kitasato University, Sagamihara 252-0373, Japan
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9
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Rabaeh KA, Hammoudeh IM, Oglat AA, Eyadeh MM, Abdel-Qader AJ, Aldweri FM, Awad SI. Polymer gel containing N,N′-methylene-bis-acrylamide (BIS) as a single monomer for radiotherapy dosimetry. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109522] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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10
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Improvement of light stability of DHR123 radio fluorogenic nano clay gel dosimeter by incorporating a new dispersant. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Marrale M, d’Errico F. Hydrogels for Three-Dimensional Ionizing-Radiation Dosimetry. Gels 2021; 7:74. [PMID: 34205640 PMCID: PMC8293215 DOI: 10.3390/gels7020074] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/28/2022] Open
Abstract
Radiation-sensitive gels are among the most recent and promising developments for radiation therapy (RT) dosimetry. RT dosimetry has the twofold goal of ensuring the quality of the treatment and the radiation protection of the patient. Benchmark dosimetry for acceptance testing and commissioning of RT systems is still based on ionization chambers. However, even the smallest chambers cannot resolve the steep dose gradients of up to 30-50% per mm generated with the most advanced techniques. While a multitude of systems based, e.g., on luminescence, silicon diodes and radiochromic materials have been developed, they do not allow the truly continuous 3D dose measurements offered by radiation-sensitive gels. The gels are tissue equivalent, so they also serve as phantoms, and their response is largely independent of radiation quality and dose rate. Some of them are infused with ferrous sulfate and rely on the radiation-induced oxidation of ferrous ions to ferric ions (Fricke-gels). Other formulations consist of monomers dispersed in a gelatinous medium (Polyacrylamide gels) and rely on radiation-induced polymerization, which creates a stable polymer structure. In both gel types, irradiation causes changes in proton relaxation rates that are proportional to locally absorbed dose and can be imaged using magnetic resonance imaging (MRI). Changes in color and/or opacification of the gels also occur upon irradiation, allowing the use of optical tomography techniques. In this work, we review both Fricke and polyacrylamide gels with emphasis on their chemical and physical properties and on their applications for radiation dosimetry.
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Affiliation(s)
- Maurizio Marrale
- Department of Physics and Chemistry, “Emilio Segrè” ATeN Center, University of Palermo, 90128 Palermo, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Catania, 95123 Catania, Italy
| | - Francesco d’Errico
- Scuola di Ingegneria, Università degli Studi di Pisa, 56126 Pisa, Italy;
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa, 56127 Pisa, Italy
- School of Medicine, Yale University New Haven, CT 06510, USA
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12
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Improved performance of N-(Hydroxymethyl)acrylamide gel dosimeter using potassium chloride for radiotherapy. RADIAT MEAS 2021. [DOI: 10.1016/j.radmeas.2021.106542] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Watanabe Y, Maeyama T, Mochizuki A, Mizukami S, Hayashi SI, Terazaki T, Muraishi H, Takei H, Gomi T, Shimono T. Verification of dose distribution in high-dose-rate brachytherapy using a nanoclay-based radio-fluorogenic gel dosimeter. Phys Med Biol 2020; 65:175008. [PMID: 32485693 DOI: 10.1088/1361-6560/ab98d2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dose distributions have become more complex with the introduction of image-guided brachytherapy in high-dose-rate (HDR) brachytherapy treatments. Therefore, to correctly execute HDR, conducting a quality assurance programme for the remote after-loading system and verifying the dose distribution in the patient treatment plan are necessary. The characteristics of the dose distribution of HDR brachytherapy are that the dose is high near the source and rapidly drops when the distance from the source increases. Therefore, a measurement tool corresponding to the characteristic is required. In this study, using an Iridium-192 (Ir-192) source, we evaluated the basic characteristics of a nanoclay-based radio-fluorogenic gel (NC-RFG) dosimeter that is a fluorescent gel dosimeter using dihydrorhodamine 123 hydrochloride as a fluorescent probe. The two-dimensional dose distribution measurements were performed at multiple source positions to simulate a clinical plan. Fluorescence images of the irradiated NC-RFG were obtained at a high resolution (0.04 mm pixel-1) using a gel scanner with excitation at 465 nm. Good linearity was confirmed up to a dose range of 100 Gy without dose rate dependence. The dose distribution measurement at the five-point source position showed good agreement with the treatment planning system calculation. The pass ratio by gamma analysis was 92.1% with a 2%/1 mm criterion. The NC-RFG dosimeter demonstrates to have the potential of being a useful tool for quality assurance of the dose distribution delivered by HDR brachytherapy. Moreover, compared with conventional gel dosimeters such as polymer gel and Fricke gel dosimeters it solves the problems of diffusion, dose rate dependence and inhibition of oxygen-induced reactions. Furthermore, it facilitates dose data to be read in a short time after irradiation, which is useful for clinical use.
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Affiliation(s)
- Yusuke Watanabe
- School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa, Japan
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Mochizuki A, Maeyama T, Watanabe Y, Mizukami S. Sensitivity enhancement of DHR123 radio-fluorogenic nanoclay gel dosimeter by incorporating surfactants and halogenides. RSC Adv 2020; 10:28798-28806. [PMID: 35520075 PMCID: PMC9055799 DOI: 10.1039/d0ra02717k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/23/2020] [Indexed: 11/23/2022] Open
Abstract
Dosimetry of spatial dose distribution of ionizing radiation in tissue equivalent materials is particularly important for cancer radiotherapy. Here, we describe a radio-fluorogenic gel-based dosimeter that has achieved 16 times higher sensitivity by incorporating surfactants and halogenides. The gel dosimeters were prepared from dihydrorhodamine 123 (DHR123) and small amounts of nano-sized clay and a radiosensitizer. By comprehensively changing the type of additives for the sensitizer (three surfactants: Triton X-100, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide, and three halogenides: trichloroacetic acid, tribromoacetic acid and 2,2,2-trichloroethanol), the increase in sensitivity can be explained by an increase in relative fluorescence quantum yield and an increase in radiation chemical yield. These highly sensitive gel dosimeters also show dose rate independent sensitivity under irradiation at 0.64 and 0.77 Gy min−1 using a 6 MV X-ray therapeutic beam from the medical linac. Dosimetry of spatial dose distribution of ionizing radiation in tissue equivalent materials using high sensitive radio-fluorogenic gel dosimeter using DHR123 with sensitizer. (Radiation therapy planning image courtesy of Varian Medical Systems, Inc. All rights reserved.)![]()
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Affiliation(s)
- Anri Mochizuki
- Department of Chemistry, School of Science, Kitasato University 1-15-1 Kitasato, Minami Sagamihara Kanagawa 252-0373 Japan
| | - Takuya Maeyama
- Department of Chemistry, School of Science, Kitasato University 1-15-1 Kitasato, Minami Sagamihara Kanagawa 252-0373 Japan
| | - Yusuke Watanabe
- School of Allied Health Sciences, Kitasato University 1-15-1 Kitasato, Minami Sagamihara Kanagawa 252-0373 Japan
| | - Shinya Mizukami
- School of Allied Health Sciences, Kitasato University 1-15-1 Kitasato, Minami Sagamihara Kanagawa 252-0373 Japan
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