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Maeda T, Hayashi H, Ando M, Kobayashi D, Nishigami R, Asahara T, Goto S, Lee C, Yamashita K, Higashino K, Konishi T, Murakami S, Maki M. Performance of elastic x-ray shield made by embedding Bi 2 O 3 particles in porous polyurethane. Med Phys 2024; 51:1061-1073. [PMID: 38103261 DOI: 10.1002/mp.16889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/22/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Many healthcare institutions have guidelines concerning the usage of protective procedures, and various x-ray shields have been used to reduce unwanted radiation exposure to medical staff and patients when using x-rays. Most x-ray shields are in the form of sheets and lack elasticity, which limits their effectiveness in shielding areas with movement, such as the thyroid. To overcome this limitation, we have developed an innovative elastic x-ray shield. PURPOSE The purpose of this study is to explain the methodology for developing and evaluating a novel elastic x-ray shield with sufficient x-ray shielding ability. Furthermore, valuable knowledge and evaluation indices are derived to assess our shield's performance. METHODS Our x-ray shield was developed through a process of embedding Bi2 O3 particles into porous polyurethane. Porous polyurethane with a thickness of 10 mm was dipped into a solution of water, metal particles, and chemical agents. Then, it was air-dried to fix the metal particles in the porous polyurethane. Thirteen investigational x-ray shields were fabricated, in which Bi2 O3 particles at various mass thicknesses (ranging from 585 to 2493 g/m2 ) were embedded. To determine the performance of the shielding material, three criteria were evaluated: (1) Dose Reduction Factor (D R F $DRF$ ), measured using inverse broad beam geometry; (2) uniformity, evaluated from the standard deviation (S D $SD$ ) of the x-ray image obtained using a clinical x-ray imaging detector; and (3) elasticity, evaluated by a compression test. RESULTS The elastic shield with small pores, containing 1200 g/m2 of the metal element (Bi), exhibited a well-balanced performance. TheD R F $DRF$ was approximately 80% for 70 kV diagnostic x-rays. This shield's elasticity was -0.62 N/mm, a loss of only 30% when compared to porous polyurethane without metal. Although the non-uniformity of the x-ray shield leads to poor shielding ability, it was found that the decrease in the shielding ability can be limited to a maximum of 6% when the shield is manufactured so that theS D $SD$ of the x-ray image of the shield is less than 10%. CONCLUSIONS It was verified that an elastic x-ray shield that offers an appropriate reduction in radiation exposure can be produced by embedding Bi2 O3 particles into porous polyurethane. Our findings can lead to the development of novel x-ray shielding products that can reduce the physical and mental stress on users.
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Affiliation(s)
- Tatsuya Maeda
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hiroaki Hayashi
- College of Medical, Pharmaceutical and Health Sciences, Kanazawa, Ishikawa, Japan
| | - Miku Ando
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Daiki Kobayashi
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Rina Nishigami
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Takashi Asahara
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
- Okayama University Hospital, Kitaku, Okayama, Japan
| | - Sota Goto
- Faculty of Health Sciences, Kobe Tokiwa University, Kobe, Hyogo, Japan
| | - Cheonghae Lee
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kazuta Yamashita
- Department of Orthopedics, School of Medicine, Tokushima University, Tokushima, Tokushima, Japan
| | - Kosaku Higashino
- Department of Orthopedics and Rehabilitation, Shikoku Medical Center for Children and Adults, Zentsuji, Kagawa, Japan
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Maehata I, Hayashi H, Kimoto N, Takegami K, Okino H, Kanazawa Y, Tominaga M. Practical method for determination of air kerma by use of an ionization chamber toward construction of a secondary X-ray field to be used in clinical examination rooms. Radiol Phys Technol 2016; 9:193-201. [PMID: 26994011 DOI: 10.1007/s12194-016-0352-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 02/10/2016] [Accepted: 02/16/2016] [Indexed: 11/28/2022]
Abstract
We propose a new practical method for the construction of an accurate secondary X-ray field using medical diagnostic X-ray equipment. For accurate measurement of the air kerma of an X-ray field, it is important to reduce and evaluate the contamination rate of scattered X-rays. To determine the rate quantitatively, we performed the following studies. First, we developed a shield box in which an ionization chamber could be set at an inner of the box to prevent detection of the X-rays scattered from the air. In addition, we made collimator plates which were placed near the X-ray source for estimation of the contamination rate by scattered X-rays from the movable diaphragm which is a component of the X-ray equipment. Then, we measured the exposure dose while changing the collimator plates, which had diameters of 25-90 mm(ϕ). The ideal value of the exposure dose was derived mathematically by extrapolation to 0 mm(ϕ). Tube voltages ranged from 40 to 130 kV. Under these irradiation conditions, we analyzed the contamination rate by the scattered X-rays. We found that the contamination rates were less than 1.7 and 2.3 %, caused by air and the movable diaphragm, respectively. The extrapolated value of the exposure dose has been determined to have an uncertainty of 0.7 %. The ionization chamber used in this study was calibrated with an accuracy of 5 %. Using this kind of ionization chamber, we can construct a secondary X-ray field with an uncertainty of 5 %.
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Affiliation(s)
- Itsumi Maehata
- School of Health Sciences, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Hiroaki Hayashi
- Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan.
| | - Natsumi Kimoto
- School of Health Sciences, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Kazuki Takegami
- Graduate School of Health Sciences, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Hiroki Okino
- Graduate School of Health Sciences, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Yuki Kanazawa
- Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
| | - Masahide Tominaga
- Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-Cho, Tokushima, Tokushima, 770-8503, Japan
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