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Rakshit S, Kulkarni MS. Development and establishment of a parallel plate ionization chamber as a transfer standard for measurement of dose to tissue in beta radiation fields. Appl Radiat Isot 2024; 206:111213. [PMID: 38340533 DOI: 10.1016/j.apradiso.2024.111213] [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: 05/04/2023] [Revised: 12/12/2023] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
A parallel-plate ionization chamber (PPC) with a nominal volume of 8.16 cm³ was developed based on theoretically simulated design parameters. Its purpose is to serve as a transfer standard for dosimetry in a beta radiation field. The entrance window of the PPC consists of an aluminized Mylar sheet with a thickness of 1.4 mg/cm2. The collecting and guard electrodes are created by applying a graphite coating on a Poly Methyl Methacrylate (PMMA) substrate with a thickness of 5 mm. The nominal sheet resistance of the graphite-coated PMMA substrate was measured using a four-probe technique and found to be approximately 800 Ω per square (Ω/□). Dosimetric characterization of the PPC was performed in the ISO 6980 reference beta radiation field, utilizing 90Sr-90Y and 85Kr beta radiation sources. The assessment included studies on short-term stability, linearity, current-to-voltage characteristics, stabilization time, and leakage current. The PPC was calibrated and established as a transfer standard using the 'Extrapolation Ionization Chamber,' recognized as an absolute standard for dose to tissue in 90Sr-90Y and 85Kr beta sources within the laboratory. The calibration coefficient of the PPC indicates an energy dependence of 0.6 % for 90Sr-90Y and 85Kr beta sources.
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Affiliation(s)
- S Rakshit
- Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India; Homi Bhabha National Institute, Mumbai, 400 094, India
| | - M S Kulkarni
- Health Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India; Homi Bhabha National Institute, Mumbai, 400 094, India.
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Nazempoor A, Poorbaygi H, Aghamiri SMR, Javanshir MR, Sheibani S, Naghdi R, Moradi S, Habibpanah A. Development of a Relative Dosimetric System for Calibration of 32P Eye Applicators Using Radiochromic Films. J Med Phys 2024; 49:49-55. [PMID: 38828074 PMCID: PMC11141744 DOI: 10.4103/jmp.jmp_99_23] [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: 07/31/2023] [Revised: 01/29/2024] [Accepted: 01/29/2024] [Indexed: 06/05/2024] Open
Abstract
Introduction Beta irradiation after bare scleral surgery of primary pterygium is an effective and safe treatment, which reduces the risk of local recurrence. Purpose Obtaining the reference dose rate for a radioactive applicator consisting of a plate as a 32P absorber, a steel window and a steel capsule. Methods Relative dosimetry and dose profile were measured using two types of radiochromic films, HD-810 and EBT1, for the 32P applicator and were compared with Monte Carlo simulation data. Dose uniformity in the 32P applicator was obtained with radiochromic HD-810 film. Results The measurement depth dose distribution data at distances up to 3.8 mm were compared with calculation data, and the values were not found to differ statistically. Depth dose distribution with a large dose gradient was determined and the dose rate data obtained 0.0053 ± 9.9% in unit of Gy/s.mCi at a 0.1 mm depth distance. Practical results indicated that the dose nonuniformity and the maximum symmetrical for the 32P applicator were 11.5% and 9.2%, respectively. Conclusions Our experiments show that the use of the radiochromic film to perform the relative dosimetric checks is feasible and the activity value with acceptable error can be determined through this indirect method.
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Affiliation(s)
- Alireza Nazempoor
- Departments of Medical Radiation Engineering, Shahid Beheshti University, Tehran, Iran
| | - Hosein Poorbaygi
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | | | - Mohammad Reza Javanshir
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Shahab Sheibani
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Reza Naghdi
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Somayeh Moradi
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
| | - Ali Habibpanah
- Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran
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Arib M, Ayad R, Alhamdan H, Ababtain M, Aldosari A, Alnahdi K, Alfadhli S, Suliman A, Alatawi AA. Development of a motorized system for the characterization of the RQR reference x-ray beams at the KFSHRC's SSDL using an extrapolation chamber. Appl Radiat Isot 2023; 202:111064. [PMID: 37866227 DOI: 10.1016/j.apradiso.2023.111064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/21/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023]
Abstract
An extrapolation chamber of type Böhm 23392, used for the dosimetry of RQR beam qualities at the Secondary Standard Dosimetry Laboratory of King Faisal Specialist Hospital, is presented. A computer-based motorized system consisting of a stepping motor coupled to the chamber's built-in micrometer screw was designed to expedite the measurements process, giving a linear relationship between the number of motor steps and the chamber depth with a Coefficient of Determination (COD) equal to 0.9990. The extrapolation chamber along with the motorized system was used to determine the extrapolation curves. The slope of the extrapolation curves, measured for the eight RQR beam qualities with a relative uncertainty between 0.17% and 0.58%, varies linearly with the beam quality expressed in terms of HVL, with a COD between 0.9995 and 1.0000.
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Affiliation(s)
- M Arib
- King Faisal Specialist Hospital & Research Center (KFSHRC), Riyadh, Kingdom of Saudi Arabia.
| | - R Ayad
- University of Tabuk, Kingdom of Saudi Arabia
| | - H Alhamdan
- King Faisal Specialist Hospital & Research Center (KFSHRC), Riyadh, Kingdom of Saudi Arabia
| | | | - A Aldosari
- King Faisal Specialist Hospital & Research Center (KFSHRC), Riyadh, Kingdom of Saudi Arabia
| | - K Alnahdi
- University of Tabuk, Kingdom of Saudi Arabia
| | - S Alfadhli
- University of Tabuk, Kingdom of Saudi Arabia
| | - A Suliman
- University of Tabuk, Kingdom of Saudi Arabia
| | - A A Alatawi
- University of Tabuk, Kingdom of Saudi Arabia
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Variance reduction technique in a beta radiation beam using an extrapolation chamber. Appl Radiat Isot 2017; 128:154-157. [PMID: 28711839 DOI: 10.1016/j.apradiso.2017.06.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 06/02/2017] [Accepted: 06/14/2017] [Indexed: 11/21/2022]
Abstract
This paper aims to show how the variance reduction technique "Geometry splitting/Russian roulette" improves the statistical error and reduces uncertainties in the determination of the absorbed dose rate in tissue using an extrapolation chamber for beta radiation. The results show that the use of this technique can increase the number of events in the chamber cavity leading to a closer approximation of simulation result with the physical problem. There was a good agreement among the experimental measurements, the certificate of manufacture and the simulation results of the absorbed dose rate values and uncertainties. The absorbed dose rate variation coefficient using the variance reduction technique "Geometry splitting/Russian roulette" was 2.85%.
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Vahabi SM, Shamsaie Zafarghandi M, Ghasemi M, Alipoor A, Shahvar A. A prototype of an extrapolation chamber for beta radiation beams of 90Sr+90Y. J Radioanal Nucl Chem 2014. [DOI: 10.1007/s10967-014-3117-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Alva-Sánchez MS, de Oliveira LN, Petchevist PC, Moreira MV, de Almeida A. Beta planar source quality assurance with the Fricke xylenol gel dosimeter. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2013.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Antonio PL, Oliveira ML, Caldas LVE. Calibration of the 90Sr+90Y ophthalmic and dermatological applicators with an extrapolation ionization minichamber. Appl Radiat Isot 2013; 85:11-3. [PMID: 24362457 DOI: 10.1016/j.apradiso.2013.10.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 09/10/2013] [Accepted: 10/10/2013] [Indexed: 10/25/2022]
Abstract
(90)Sr+(90)Y clinical applicators are used for brachytherapy in Brazilian clinics even though they are not manufactured anymore. Such sources must be calibrated periodically, and one of the calibration methods in use is ionometry with extrapolation ionization chambers. (90)Sr+(90)Y clinical applicators were calibrated using an extrapolation minichamber developed at the Calibration Laboratory at IPEN. The obtained results agree satisfactorily with the data provided in calibration certificates of the sources.
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Affiliation(s)
- Patrícia L Antonio
- Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, IPEN/CNEN-SP, Av. Prof. Lineu Prestes, 2242, 05508-000 São Paulo, SP, Brazil.
| | - Mércia L Oliveira
- Centro Regional de Ciências Nucleares, Comissão Nacional de Energia Nuclear, CRCN/CNEN, Av. Prof. Luis Freire, 200, 50740-540 Recife, PE, Brazil
| | - Linda V E Caldas
- Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, IPEN/CNEN-SP, Av. Prof. Lineu Prestes, 2242, 05508-000 São Paulo, SP, Brazil
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da Silva EAB, Caldas LVE. Application of extrapolation chambers in low-energy X-rays as reference systems. Appl Radiat Isot 2012; 70:1411-6. [PMID: 22520689 DOI: 10.1016/j.apradiso.2012.03.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 11/29/2022]
Abstract
Extrapolation chambers are instruments designed to measure doses of low-energy radiations, mainly beta radiation. In this work, a commercial extrapolation chamber and a homemade extrapolation chamber were applied in measurements using standard radiotherapy X-ray beams. Saturation curves and polarity effect as well as short- and medium-term stabilities were obtained, and these results are within the recommendations of the International Electrotechnical Commission (IEC). The response linearity and the extrapolation curves were also obtained, and they presented good behavior. The results show the usefulness of these extrapolation chambers in low-energy X-ray beams.
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Affiliation(s)
- Eric A B da Silva
- Instituto de Pesquisas Energéticas e Nucleares, Comissão Nacional de Energia Nuclear, IPEN/CNEN-SP, 05508-000 São Paulo, SP, Brazil
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Comparison of calibration results for an extrapolation chamber obtained with different 90Sr+90Y secondary standard sources. Appl Radiat Isot 2012; 70:388-91. [DOI: 10.1016/j.apradiso.2011.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 10/18/2011] [Accepted: 10/18/2011] [Indexed: 11/18/2022]
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The role of radiotherapy in the treatment of pterygium: A review of the literature including more than 6000 treated lesions. Cancer Radiother 2011; 15:140-7. [DOI: 10.1016/j.canrad.2010.03.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 03/11/2010] [Accepted: 03/23/2010] [Indexed: 11/20/2022]
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Costa AMD, Caldas LVE. Câmara de ionização de placas paralelas para radiação-X de radiografia convencional e mamografia. Radiol Bras 2008. [DOI: 10.1590/s0100-39842008000100011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Desenvolver uma câmara de ionização de placas paralelas de dupla face para determinação de kerma no ar e taxa de kerma no ar em campos de radiação-X utilizados em radiografia convencional e mamografia. MATERIAIS E MÉTODOS: A câmara desenvolvida tem janelas de entrada de poliéster aluminizado, elétrodos internos e anéis de guarda de alumínio em uma face (face A) e de grafite na outra (face G). Neste trabalho foram testadas as características operacionais de linearidade, dependência angular e energética de resposta. RESULTADOS: A linearidade de resposta foi de 0,86% para a face A e de 0,92% para a face G. Para ângulos de incidência da radiação de 0° a ± 5°, a variação da resposta relativa foi menor que 0,8% para ambas as faces da câmara. A dependência energética de resposta foi de 0,8% para a face A nas qualidades de raios-X para diagnóstico convencional e de 2,4% para a face G da câmara nas qualidades de raios-X para mamografia. CONCLUSÃO: Esta câmara pode ser utilizada rotineiramente na determinação de kerma no ar e taxa de kerma no ar em feixes de raios-X utilizados em radiografia convencional e mamografia.
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Oliveira ML, Caldas LVE. Performance of a prototype of an extrapolation minichamber in various radiation beams. Appl Radiat Isot 2007; 65:975-9. [PMID: 17574854 DOI: 10.1016/j.apradiso.2007.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 01/10/2007] [Accepted: 03/22/2007] [Indexed: 11/26/2022]
Abstract
An extrapolation minichamber was developed for measuring doses from weakly penetrating types of radiation. The chamber was tested at the radiotherapeutic dose level in a beam from a (90)Sr+(90)Y check source, in a beam from a plane (90)Sr+(90)Y ophthalmic applicator, and in several reference beams from an X-ray tube. Saturation, ion collection efficiency, stabilization time, extrapolation curves, linearity of chamber response vs. air kerma rate, and dependences of the response on the energy and irradiation angle were characterized. The results are satisfactory; they show that the chamber can be used in the dosimetry of (90)Sr+(90)Y beta particles and low-energy X-ray beams.
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Affiliation(s)
- M L Oliveira
- Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Comissão Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 São Paulo, SP, Brazil.
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