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Okuhata K, Monzen H, Nakamura Y, Takai G, Nagano K, Nakamura K, Kubo K, Hosono M. Effectiveness of shielding materials against 177Lu gamma rays and the corresponding distance relationship. Ann Nucl Med 2023; 37:629-634. [PMID: 37596439 DOI: 10.1007/s12149-023-01860-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 08/07/2023] [Indexed: 08/20/2023]
Abstract
OBJECTIVE The purpose of this study is to determine the dose reduction of different shielding materials at various distances from a 177Lu photon radiation source. METHODS Two protective aprons with lead equivalent thicknesses of 0.25 mm and 0.35 mm and tungsten-containing rubber (TCR) were used as shielding materials. A vial containing 177Lu was sealed in a lead container so that a narrow beam went out through a 3 mm-diameter hole. The dose rate was measured at distances of 0, 10, 50, 100, and 200 cm from the source using a NaI scintillation survey meter to obtain the rate of dose reduction. TCR was tested with thicknesses ranging from 0.3 to 1.0 mm at 0.1 mm intervals and from 1.0 to 4.0 mm at 0.5 mm intervals. RESULTS At distances of 0, 10, 50, 100, and 200 cm, the dose reduction for the lead equivalent thickness of 0.25 mm were 32.7%, 54.5%, 93.1%, 97.9%, and 99.6%, respectively; and for the lead equivalent thickness of 0.35 mm were 53.4%, 70.6%, 95.6%, 98.9%, and 99.6%, respectively. Without any shielding, the dose rate decreased by 34.4% at 10 cm and by 88.8% at 50 cm from the radiation source. The dose reduction for the TCR thickness of 3.5 mm was 89.8% at 0 cm and 93.3% at 10 cm. The TCR thickness of 0.4 mm provided a dose reduction comparable to or greater than that of the 0.25 mm lead equivalent, whereas the TCR thickness of 1.0 mm or greater provided a dose reduction comparable to that of the 0.35 mm lead equivalent. CONCLUSIONS Achieving a reduction of 95% or more requires the 0.25 mm lead equivalent for a distance of 100 cm, the 0.35 mm lead equivalent for 50 cm, the TCR thickness of 0.3 mm for 100 cm, or the TCR thickness of 0.9 mm for 50 cm. Without wearing a protective apron, a reduction of approximately 95% is observed at distances greater than 100 cm. These findings would be useful for medical staff engaging in related activities.
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Affiliation(s)
- Katsuya Okuhata
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan.
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Yasunori Nakamura
- Department of Radiology, University Hospital, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 6028566, Japan
| | - Go Takai
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Keiji Nagano
- Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Kenji Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Kazuki Kubo
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
| | - Makoto Hosono
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama-shi, Osaka, 5898511, Japan
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Yanagi Y, Monzen H, Tamura M, Otsuka M, Nishimura Y. New strategy of a lung compensating technique with STR for total body irradiation. J Appl Clin Med Phys 2022; 23:e13791. [PMID: 36197733 PMCID: PMC9588260 DOI: 10.1002/acm2.13791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose To determine the thickness of a soft variable shape tungsten rubber (STR) as a lung compensating filter in total body irradiation. Methods A tough water (TW) phantom and tough lung (TL) phantom were used as water and lung‐equivalent phantoms. The TW with a thickness of 3 cm simulating the thoracic wall was used (upper layer). The TW or TL with a thickness from 1 to 15 cm (1 cm increments) was placed beneath the upper layer (middle layer). The TW with a thickness of 5 cm simulating the mediastinum was placed beneath the middle layer (lower layer), and a farmer ionization chamber was placed beneath this layer. The relative doses of a 10 MV X‐rays were then measured. The TL was compensated in 1 mm increments from 1 to 11 mm of the STR, and the thickness of the STR at the same dose of TW (water equivalent) was obtained. Results The compensating ability of STR increased as the thickness of the TL increased, and an STR with a thickness of 1 mm reduced the dose by 2%–4%, depending on the thickness of lung. The STR thickness as an equivalent dose of TW per cm of TL was approximately linear, and the thickness was 0.62 mm/cm of TL. Conclusion The STR can be used as a lung compensating filter for a water equivalent dose with 0.62 mm of STR per cm of lung.
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Affiliation(s)
- Yuya Yanagi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiology, Shiga University of Medical Science Hospital, Otsu, Shiga, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Masakazu Otsuka
- Department of Radiology Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Hattori S, Monzen H, Tamura M, Kosaka H, Nakamura Y, Nishimura Y. Estimating radiation exposure of the brain of a physician with a protective flap in interventional radiology: A phantom study. J Appl Clin Med Phys 2022; 23:e13532. [PMID: 35045212 PMCID: PMC8906205 DOI: 10.1002/acm2.13532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/30/2021] [Accepted: 12/18/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The efficiency of protective equipment for the brain has not been verified at the left anterior oblique (LAO) position, which is commonly used in clinical procedures. The purpose of this study was to investigate radiation exposure of the brain in interventional radiology (IR) and the shielding ability of a new protective flap. METHODS We made a flap that combined a protective cap with a left lateral face shield. The flap was made of tungsten-containing rubber (TCR). An anthropomorphic head phantom was placed at the physician's position, and air kerma rates (μGy/min and μGy/15s) were measured by electronic dosimeter at three locations: the surface of the left side of the head, and the left and right temporal lobes with the protective cap and the flap in fluoroscopy and cine modes. The X-ray tube was at the lower left side of the physician, and its angles were LAO60 and LAO60CAU40. The tube voltage (95-125 kV), tube current (4.7-732 mA), and air kerma rate (27.8-1078 mGy/min) were automatically adjusted by the X-ray system. We obtained the cap and the flap shielding efficiencies. RESULTS In cine mode at LAO60CAU40, the shielding efficiencies on the surface of the left side of the head and left temporal lobe with the cap were 92.6% and 5.1%, respectively, and the corresponding shielding efficiencies with the flap were 92.5% and 86.1%, respectively. The flap can reduce radiation exposure of the brain more than the cap alone. CONCLUSIONS At the left anterior oblique in interventional radiology, the flap can reduce exposure to the brain.
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Affiliation(s)
- Shota Hattori
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiological Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan.,Department of Radiological Center, Kindai University Hospital, Osakasayama, Osaka, Japan
| | - Yasunori Nakamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osakasayama, Osaka, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, Osakasayama, Osaka, Japan
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Okuhata K, Tamura M, Monzen H, Nishimura Y. Dosimetric characteristics of a thin bolus made of variable shape tungsten rubber for photon radiotherapy. Phys Eng Sci Med 2021; 44:1249-1255. [PMID: 34542835 DOI: 10.1007/s13246-021-01059-2] [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: 05/20/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
In this study, we aim to clarify the dosimetric characteristics of a real time variable shape rubber containing tungsten (STR) as a thin bolus in 6-MV photon radiotherapy. The percentage depth doses (PDDs) and lateral dose profiles (irradiation field = 10 × 10 cm2) in the water-equivalent phantom were measured and compared between no bolus, a commercial 5-mm gel bolus, and 0.5-, 1-, 2-, and 3-mm STR boluses. The characteristics of the PDDs were evaluated according to relative doses at 1 mm depth (D1mm) and depth of maximum dose (dmax). To determine the distance of the shift caused by the STR bolus, the PDD value at a depth of 100 mm without a bolus was obtained. For each STR thickness, the difference between the depth corresponding to this PDD value and 100 mm was calculated. The penumbra size and width of the 50% dose were evaluated using lateral dose profiles. The D1mm with no bolus, 5-mm gel bolus, and 0.5-, 1-, 2-, and 3-mm STR boluses were 47.6%, 91.5%, 78.2%, 86.6%, 89.3%, and 89.4%, respectively, and the respective dmax values were 15, 10, 13, 12, 11, and 10 mm. The shifting distance of the 0.5-, 1-, 2-, and 3-mm STR boluses were 2.7, 4.4, 4.8, and 4.9 mm, respectively. There were no differences for those in lateral dose profiles. The 1-mm-thick STR thin bolus shifted the depth dose profile by 4.4 mm and could be used as a customized bolus for photon radiotherapy.
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Affiliation(s)
- Katsuya Okuhata
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan.,Department of Radiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka-shi, Osaka, 5530003, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan.
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Onohigashi, Osakasayama, Osaka, 5898511, Japan
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Wakabayashi K, Monzen H, Tamura M, Matsumoto K, Takei Y, Nishimura Y. Dosimetric evaluation of skin collimation with tungsten rubber for electron radiotherapy: A Monte Carlo study. J Appl Clin Med Phys 2021; 22:63-70. [PMID: 33634955 PMCID: PMC8035551 DOI: 10.1002/acm2.13210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 11/15/2022] Open
Abstract
PURPOSE Skin collimation provides a sharp penumbra for electron beams, while the effect of bremsstrahlung from shielding materials is a concern. This phantom study was conducted to evaluate the safety and efficacy of a real-time variable shape rubber containing-tungsten (STR) that can be placed on a patient's skin. METHODS Electron beam profiles were acquired with the STR placed on a water-equivalent phantom and low melting-point alloy (LMA) placed at the applicator according to commonly used procedures (field sizes: 20- and 40-mm diameters). Depth and lateral dose profiles for 6- and 12-MeV electron beams were obtained by Monte Carlo (MC) simulations and were benchmarked against film measurements. The width of the off-axis distance between 80% and 20% doses (P80-20 ) and the maximum dose were obtained from the lateral dose profiles. Bremsstrahlung emission was analyzed by MC simulations at the depth of maximum dose (R100 ). RESULTS The depth dose profiles calculated by the MC simulations were consistently within 2% of the measurements. The P80-20 at R100 for 20- and 40-mm diameters were 4.0 mm vs. 7.6 mm (STR vs. LMA) and 4.5 mm vs. 9.2 mm, respectively, for the 6-MeV electron beam with 7.0-mm-thick STR, and 2.7 mm vs. 5.6 mm and 4.5 mm vs. 7.1 mm, respectively, for the 12-MeV electron beam with 12.0-mm-thick STR. A hotspot was not observed on the lateral dose profiles obtained with the STR at R100 . The bremsstrahlung emission under the region shielded by the STR was comparable to that obtained with the LMA, even though the STR was placed on the surface of the phantom. CONCLUSIONS Skin collimator with STR provided superior dosimetric characteristics and comparable bremsstrahlung emission to LMA collimator at the applicator. STR could be a new tool for the safe and efficient delivery of electron radiotherapy.
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Affiliation(s)
- Kazuki Wakabayashi
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Hajime Monzen
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Mikoto Tamura
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Kenji Matsumoto
- Department of Central RadiologyKindai University HospitalOsakaJapan
| | - Yoshiki Takei
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsakaJapan
| | - Yasumasa Nishimura
- Department of Radiation OncologyFaculty of MedicineKindai UniversityOsakaJapan
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Yanagi Y, Tamura M, Monzen H, Matsumoto K, Takei Y, Noma K, Kida T. [Application of Real-time Variable Shape Tungsten Rubber for Nail Radiation Protection in the Total Skin Electron Beam (TSEB) Therapy]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:145-152. [PMID: 33612692 DOI: 10.6009/jjrt.2021_jsrt_77.2.145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
PURPOSE This study investigated whether real-time variable shape tungsten rubber (STR) could be applied for nail radiation protection in total skin electron beam (TSEB) therapy. METHODS Simulated finger phantoms were made from syringes filled with physiological saline of volumes 5, 10, 20, and 30 ml (inner diameters of 14.1, 17.0, 21.7, and 25.3 mm, respectively). Gafchromic film was applied to the phantom, and lead (thickness 1-3 mm) or STR (thickness 1-4 mm) with an area of 4´1.5 cm was used to cover the film. A 6 MeV electron beam with an 8 mm acrylic board was then used to irradiate the phantom. The source-surface distance (SSD) was 444 cm, the field size was 36´36 cm at SSD of 100 cm without an electron applicator, and the monitor unit was 2000 MU. The shielding rates were obtained from the dose profiles. RESULTS The mean values of the shielding rate values for all phantoms were 50.1, 97.6, and 98.7% for 1, 2, and 3 mm of lead, respectively, and -13.6, 53.9, 91.2, and 99.4% for 1, 2, 3, and 4 mm of STR, respectively. CONCLUSION STR with a thickness of 4 mm had the same shielding properties as lead with a thickness of 3 mm, which was an approximately 100% shielding rate. STR could therefore be used in TSEB therapy instead of lead.
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Affiliation(s)
- Yuya Yanagi
- Department of Radiology, Shiga University of Medical Science Hospital
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
- Department of Radiology, Kindai University Hospital
| | - Yoshiki Takei
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
- Department of Radiology, Kindai University Nara Hospital
| | - Kazuo Noma
- Department of Radiology, Shiga University of Medical Science Hospital
| | - Tetsuo Kida
- Department of Radiology, Shiga University of Medical Science Hospital
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Matsumoto K, Tamura M, Otsuka M, Wakabayashi K, Kijima K, Monzen H. [Dosimetric Characteristics of a Real Time Shapeable Tungsten Containing Rubber with Electron Beams]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2020; 76:1248-1255. [PMID: 33342943 DOI: 10.6009/jjrt.2020_jsrt_76.12.1248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE This study investigated the dosimetric characteristics of electron beams shaped with a real-time shapeable tungsten-containing rubber (STR) collimator. METHODS Circular irradiation fields of 40 mm diameter were shaped using STR or low melting-point alloy (LMA) placed on the electron applicator. The STR heated with approximately 70-degree warm water was molded into the template bottom of the applicator. Percent depth doses (PDDs) and lateral dose profiles of 6 and 12 MeV electron beams were measured and compared between STR and LMA. For the PDDs, the depths of maximum dose (dmax), 90% dose (d90), and 80% dose (d80) were evaluated. For the lateral dose profiles, penumbra as the width of the off-axis distance from 80% to 20% doses and treatment diameter covering over 90% dose were evaluated at the surface, dmax, d90, and d80. The transmission of the STR was also investigated at thicknesses fit to electron applicator for 6 and 12 MeV electron beams. RESULTS The STR was softened with 70-degree warm water. Therefore, it was easy to mold it and attach the applicator. The PDDs and penumbras at the surface, dmax, d90, and d80 for the STR were almost equal to those for the LMA with 6 and 12 MeV electron beams. The treatment diameters covering over 90% dose for the irradiation fields with 40 mm diameter at dmax (LMA vs. STR) were 20.9 vs. 21.1 mm and 19.2 vs. 18.4 mm for 6 and 12 MeV electron beams, respectively. The transmission of the STR was almost same as that of LMA. CONCLUSIONS The dosimetric characteristics of the STR on the electron applicator were almost same as those of the LMA. The heated STR was shaped easily, flexibly, and immediately. The STR can be used as a substitute for LMA in electron radiotherapy.
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Affiliation(s)
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
| | | | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University.,Department of Central Radiology, Wakayama Medical University Hospital
| | - Kenta Kijima
- Department of Medical Technology, University Hospital, Kyoto Prefectural University of Medicine
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University
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Mansouri E, Mesbahi A, Malekzadeh R, Mansouri A. Shielding characteristics of nanocomposites for protection against X- and gamma rays in medical applications: effect of particle size, photon energy and nano-particle concentration. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2020; 59:583-600. [PMID: 32780196 DOI: 10.1007/s00411-020-00865-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
In recent decades, nanomaterials have been extensively investigated for many applications. Composites doped with different metal nanoparticles have been suggested as effective shielding materials to replace conventional lead-based materials. The use of concretes as structural and radiation protective material has been influenced by the addition of nanomaterials. Several elements with high atomic number and density, such as lead, bismuth, and tungsten, have the potential to form nanoparticles that offer significant enhancements in the shielding ability of composites. Their performance for a range of particle concentrations, particle sizes, and photon energies have been investigated. This review is an attempt to gather the data published in the literature about the application of nanomaterials in radiation shielding, including the use of polymer composites and concretes for protection against X-rays and gamma radiation.
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Affiliation(s)
- Elham Mansouri
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Asghar Mesbahi
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Reza Malekzadeh
- Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ahmad Mansouri
- Department of Materials Engineering, University of Tabriz, 51666-16471, Tabriz, Iran
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Takei Y, Kamomae T, Monzen H, Nakaya T, Sugita K, Suzuki K, Oguchi H, Tamura M, Nishimura Y. Feasibility of using tungsten functional paper as a thin bolus for electron beam radiotherapy. Phys Eng Sci Med 2020; 43:1101-1111. [PMID: 32785883 DOI: 10.1007/s13246-020-00910-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 07/25/2020] [Indexed: 11/30/2022]
Abstract
Containing 80% tungsten by weight, tungsten functional paper (TFP) is a radiation-shielding material that is lightweight, flexible, disposable, and easy to cut. Through experimental measurements and Monte Carlo simulations, we investigated the feasibility of using TFP as a bolus in electron beam radiotherapy. Commercial boluses of thickness 5 and 10 mm and from one to nine layers of TFPs (0.3-2.7 mm) were positioned on the surface of water-equivalent phantoms. The percentage depth dose curves and transverse dose profiles were measured using a 9-MeV electron beam from a clinical linear accelerator. Normalized to the value at the depth of maximum dose without bolus, the relative doses at the phantom surface for no bolus, 5-mm bolus, 10-mm bolus, 1 TFP, 3 TFPs, 6 TFPs, and 9 TFPs were 78%, 88%, 92%, 84%, 92%, 102%, and 112%, respectively; the therapeutic depths corresponding to a 90% dose level were 29.1 mm, 22.7 mm, 17.7 mm, 26.6 mm, 23.2 mm, 19.3 mm, and 15.8 mm, respectively. The TFP contributed to increased skin dose and provided dose uniformity within the target volume. However, it also resulted in increased lateral constriction and penumbra width. The results of Monte Carlo simulation produced similar trends as the experimental measurements. Our findings suggest that using TFP as a novel thin and flexible skin bolus for electron beam radiotherapy is feasible.
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Affiliation(s)
- Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, 1248-1 Otoda-cho, Ikoma, Nara, 630-0293, Japan.,Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Takeshi Kamomae
- Department of Radiology, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
| | - Takayoshi Nakaya
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kazuma Sugita
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kentaro Suzuki
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Hiroshi Oguchi
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
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Monzen H, Tamura M, Kijima K, Otsuka M, Matsumoto K, Wakabayashi K, Choi MG, Yoon DK, Doi H, Akiyama H, Nishimura Y. Estimation of radiation shielding ability in electron therapy and brachytherapy with real time variable shape tungsten rubber. Phys Med 2019; 66:29-35. [PMID: 31550531 DOI: 10.1016/j.ejmp.2019.09.233] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/28/2019] [Accepted: 09/14/2019] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To clarify the physical characteristics of a newly developed real time variable shape rubber containing tungsten (STR) with changes in heat and estimate its shielding abilities against electron beams and γ-rays from 192Ir. METHODS Dynamic mechanical analysis for the STR (density = 7.3 g/cm3) was conducted at a frequency of 1.0 Hz in the temperature range of -60 °C to 60 °C. We evaluated tanδ, defined as the ratio (E″/E') between the storage modulus (E') and loss modulus (E″). The transmission rates were measured against 6- and 12-MeV electron beams and the percentage depth dose and lateral dose profile were compared with low-melting alloy (LMA). For the shielding rate of 192Ir against γ-rays, measurement data and Monte Carlo simulation data were obtained with STR thickness ranging from 1.0 mm to 16.0 mm. RESULTS At 36 °C, the tanδ value was 0.520, while at 60 °C, this value was 1.016. For 6- and 12-MeV electron beams, the transmission rates decreased with increasing STR thickness and reached plateaus at approximately 1.0% and 4.0% with STR thickness of >7.0 and >12.0 mm, respectively. The dose distributions were almost equal to those for LMA. Against γ-rays, the thickness of STR that obtained a 50% attenuation rate for 192Ir was 5.804 mm. The Monte Carlo calculation results were 2.6% higher on average than the measurement results. CONCLUSION The STR can be changed shape in real time at 60 °C and maintains its shape at body temperatures. It has adequate shielding abilities against megavoltage electron beams and γ-rays from 192Ir.
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Affiliation(s)
- Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan.
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan
| | - Kenta Kijima
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan
| | - Masakazu Otsuka
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan; Department of Central Radiology, Kindai University Hospital, Osaka-Sayama, Osaka 589-8511, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan; Department of Central Radiology, Kindai University Hospital, Osaka-Sayama, Osaka 589-8511, Japan
| | - Kazuki Wakabayashi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan
| | - Min-Geon Choi
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, Osaka-Sayama, Osaka 589-8511, Japan; Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 06591, South Korea
| | - Do-Kun Yoon
- Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 06591, South Korea
| | - Hiroshi Doi
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan
| | - Hironori Akiyama
- Department of Oral Radiology, Osaka Dental University, 1-5-17 Otemae Chuo-ku, Osaka 540-0008, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan
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Kosaka H, Monzen H, Matsumoto K, Tamura M, Nishimura Y. Reduction of Operator Hand Exposure in Interventional Radiology With a Novel Finger Sack Using Tungsten-containing Rubber. HEALTH PHYSICS 2019; 116:625-630. [PMID: 30688684 DOI: 10.1097/hp.0000000000000992] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The purpose of this study was to evaluate the x-ray shielding ability of a novel tungsten-particle-containing rubber-based finger sack for use in interventional radiology. Shielding rates for the air kerma (mGy m) were measured using a semiconductor dosimeter with and without the finger sack and commercial lead gloves, at a 20 cm distance from the field of view. A C-arm digital angiography system was used with x-ray tube voltages of 60, 80, 100, and 120 kVp. In addition, the 70 μm dose equivalent to the operator's finger was measured using fluorescent glass dosimeters with and without the finger sack during interventional radiology examinations. The x-ray shielding rates for 60, 80, 100, and 120 kV x rays were 98.0 ± 0.03%, 94.8 ± 0.05%, 92.3 ± 0.12%, and 90.1 ± 0.03%, respectively, with the finger sack and 69.8 ± 0.39%, 61.0 ± 0.53%, 52.3 ± 0.52%, and 47.0 ± 0.69% with the lead gloves. The x-ray shielding rates for the fluoroscopy and cine mode with the finger sack were 91.3 ± 0.21% and 56.5 ± 0.58%, respectively, while with the lead gloves they were 96.5 ± 0.04% and 67.6 ± 0.33%. The 70 μm dose equivalent for the operator's finger exposure dose was reduced by approximately 39.4% using the finger sack. The finger shields were more user friendly, had excellent radiation shielding ability against x rays, and should reduce finger exposure in interventional radiology.
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Affiliation(s)
- Hiroyuki Kosaka
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan
| | - Kenji Matsumoto
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, Osaka, Japan
| | - Yasumasa Nishimura
- Faculty of Medicine, Department of Radiation Oncology, Kindai University, Osaka, Japan
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