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Esen N, Ramachandran P, Geso M. SABR pre-treatment checks using alanine and nanoDot dosimeters. JOURNAL OF RADIATION RESEARCH 2021:rrab056. [PMID: 34668563 DOI: 10.1093/jrr/rrab056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/05/2021] [Accepted: 12/19/2019] [Indexed: 06/13/2023]
Abstract
Stereotactic Ablative Radiotherapy (SABR) remains one of the preferred treatment techniques for early-stage cancer. It can be extended to more treatment locales involving the sternum, scapula and spine. This work investigates SABR checks using Alanine and nanoDot dosimeter for three treatment sites, including sternum, spine and scapula. Alanine and nanoDot dosimeters' performances were verified using a 6 MV photon beam before SABR pretreatment verifications. Each dosimeter was placed inside customized designed inserts into a Rod Phantom (in-house phantom) made of Perspex that mimics the human body for a SABR check. Electron Paramagnetic Resonance (EPR) spectrometer, Bruker EleXsys E500 (9.5 GHz) and Microstar (Landauer Inc.) Reader was employed to acquire the irradiated alanine and nanoDot dosimeters' signal, respectively. Both dosimeters treatment sites are expressed as mean ± standard deviation (SD) of the measured and Eclipse calculated dose Alanine (19.59 ± 0.24, 17.98 ± 0.15, 17.95 ± 0.18) and nanoDot (19.70 ± 0.43, 17.05 ± 0.08, 17.95 ± 0.98) for spine, scapula and sternum, respectively. The percentage difference between alanine and nanoDot dosimeters was within 2% for sternum and scapula but 2.4% for spine cases. These results demonstrate Alanine and nanoDot dosimeters' potential usefulness for SABR pretreatment quality assurance (QA).
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Affiliation(s)
- Nsikan Esen
- Peter MacCallum Cancer Centre, Melbourne 3165, Australia
- Medical Radiations Science, RMIT University, Bundoora 3082, Australia
| | - Prabhakar Ramachandran
- Medical Radiations Science, RMIT University, Bundoora 3082, Australia
- Princess Alexandra Hospital, Woolloongabba, Queensland 4102, Australia
| | - Moshi Geso
- Medical Radiations Science, RMIT University, Bundoora 3082, Australia
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2
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De Saint-Hubert M, De Angelis C, Knežević Ž, Michalec B, Reniers B, Pyszka E, Stolarczyk L, Swakon J, Foltynska G, Wochnik A, Parisi A, Majer M, Harrison RM, Kopec R, Vanhavere F, Olko P. Characterization of passive dosimeters in proton pencil beam scanning - A EURADOS intercomparison for mailed dosimetry audits in proton therapy centres. Phys Med 2021; 82:134-143. [PMID: 33611050 DOI: 10.1016/j.ejmp.2021.01.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/18/2020] [Accepted: 01/15/2021] [Indexed: 11/27/2022] Open
Abstract
The lack of mailed dosimetry audits of proton therapy centres in Europe has encouraged researchers of EURADOS Working Group 9 (WG9) to compare response of several existing passive detector systems in therapeutic pencil beam scanning. Alanine Electron Paramagnetic Resonance dosimetry systems from 3 different institutes (ISS, Italy; UH, Belgium and IFJ PAN, Poland), natLiF:Mg, Ti (MTS-N) and natLiF:Mg, Cu, P (MCP-N) thermoluminescent dosimeters (TLDs), GD-352M radiophotoluminescent glass dosimeters (RPLGDs) and Al2O3:C optically stimulated dosimeters (OSLDs) were evaluate. Dosimeter repeatability, batch reproducibility and response in therapeutic Pencil Beam Scanning were verified for implementation as mail auditing system. Alanine detectors demonstrated the lowest linear energy transfer (LET) dependence with an agreement between measured and treatment planning system (TPS) dose below 1%. The OSLDs measured on average a 6.3% lower dose compared to TPS calculation, with no significant difference between varying modulations and ranges. Both GD-352M and MCP-N measured a lower dose than the TPS and luminescent response was dependent on the LET of the therapeutic proton beam. Thermoluminescent response of MTS-N was also found to be dependent on the LET and a higher dose than TPS was measured with the most pronounced increase of 11%. As alanine detectors are characterized by the lowest energy dependence for different parameters of therapeutic pencil beam scanning they are suitable candidates for mail auditing in proton therapy. The response of luminescence detector systems have shown promises even though more careful calibration and corrections are needed for its implementation as part of a mailed dosimetry audit system.
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Affiliation(s)
- M De Saint-Hubert
- Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, BE-2400 Mol, Belgium.
| | - C De Angelis
- Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161 Rome, Italy
| | - Ž Knežević
- Ruđer Bošković Institute (RBI), Bijenička 54, Zagreb, Croatia
| | - B Michalec
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - B Reniers
- Research Group NuTeC, University Hasselt (UH), Agoralaan Gebouw H, B-3590 Diepenbeek, Belgium
| | - E Pyszka
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - L Stolarczyk
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - J Swakon
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - G Foltynska
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - A Wochnik
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - A Parisi
- Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, BE-2400 Mol, Belgium
| | - M Majer
- Ruđer Bošković Institute (RBI), Bijenička 54, Zagreb, Croatia
| | - R M Harrison
- University of Newcastle, Newcastle Upon Tyne NE2 4HH, UK
| | - R Kopec
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
| | - F Vanhavere
- Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, BE-2400 Mol, Belgium
| | - P Olko
- Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN), Radzikowskiego 152, 31-342 Krakow, Poland
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Höfel S, Stehle M, Zwicker F, Fix MK, Drescher M. A practical EPR dosimetry system for routine use in radiotherapy: uncertainty analysis of lithium formate dosimeters at the therapeutic dose level. Phys Med Biol 2021; 66:045005. [PMID: 32422627 DOI: 10.1088/1361-6560/ab9414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In electron paramagnetic resonance (EPR) dosimetry, solid dosimeter materials such as alanine (AL) or, more recently, lithium formate monohydrate (LFM) are typically used. These materials offer high potential for applications in radiotherapy based on their favorable dosimetric properties. Nevertheless, EPR dosimetry is not widespread in the clinics. This work presents an uncertainty analysis of EPR dosimetry in the dose range from 1 to 70 Gy using a compact spectrometer and applying a practical procedure being suitable for routine use in radiotherapy. The performances of self-pressed LFM pellets and commercial AL pellets are compared side by side. All pellets had a diameter of 4 mm and a height of 2 mm (AL) or 4 mm (LFM). The mean pellet mass was 35.81 mg and 73.81 mg for AL and LFM, respectively. Before irradiation, the pellets were stored for at least 8 weeks at 34 ± 2% relative humidity. For irradiation, the pellets were put inside an airtight capsule. In total, 25 pellets per material were examined. The pellets were irradiated at a temperature of 25 ± 2.5 (2σ) °C to doses of either 1, 5, 20, 50 or 70 Gy (five pellets per dose value and material) by a clinical 6 MV photon beam. Measurement uncertainties were obtained from five independent readouts per pellet within five weeks following irradiation using a benchtop EPR spectrometer. The measurement time of a single readout was restricted to 10 min per pellet. Dose values were derived from EPR signal amplitudes using a specifically developed spectral fitting procedure. Signal fading characteristics were analyzed and taken into account during evaluation. The relative dose uncertainties (1σ) for a single readout at doses ≥ 5 Gy are below 2.8% (AL) and 1.1% (LFM) but increase to 12.3% (AL) and 2.6% (LFM) at 1 Gy. By averaging five independent readouts, the uncertainties at 1 Gy decrease to 2.6% (AL) and 0.8% (LFM). In terms of dose uncertainty, the LFM pellets are superior to the commercial AL pellets owing to their narrower EPR spectrum and approximately doubled mass resulting in higher EPR signal intensities. In case of the LFM pellets, the EPR dosimetry system shows a high level of precision (< 3%) down to 1 Gy being preferable for applications in radiotherapy. The uncertainties can be further decreased by averaging multiple dose values from independent readouts.
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Affiliation(s)
- Sebastian Höfel
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Germany. Klinik und Praxis für Strahlentherapie am Klinikum Konstanz, Konstanz, Germany
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The first KREDOS-EPR intercomparison exercise using alanine pellet dosimeter in South Korea. NUCLEAR ENGINEERING AND TECHNOLOGY 2020. [DOI: 10.1016/j.net.2020.03.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tuta CS, Amiot MN, Sommier L, Ioan RM. Alanine pellets comparison using EPR dosimetry in the frame of quality assurance for a Gamma Knife system in Romania. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.108653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Investigation of IRGANOX®1076 as a dosimeter for clinical X-ray, electron and proton beams and its EPR angular response. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.08.002] [Citation(s) in RCA: 5] [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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Kunst J, Kopeć R, Kukołowicz P, Mojżeszek N, Sadowski B, Stolarczyk L, Ślusarczyk-Kacprzyk W, Toboła A, Olko P. Mailed dosimetric audit of therapeutic proton beams using thermoluminescence MTS-N (LiF:Mg,Ti) powder – First results. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Al-Karmi AM, Ayaz AAH, Al-Enezi MS, Abdel-Rahman W, Dwaikat N. Verification of the pure alanine in PMMA tube dosimeter applicability for dosimetry of radiotherapy photon beams: a feasibility study. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:425-34. [PMID: 26138456 DOI: 10.1007/s13246-015-0360-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 06/29/2015] [Indexed: 12/01/2022]
Abstract
Alanine dosimeters in the form of pure alanine powder in PMMA plastic tubes were investigated for dosimetry in a clinical application. Electron paramagnetic resonance (EPR) spectroscopy was used to measure absorbed radiation doses by detection of signals from radicals generated in irradiated alanine. The measurements were performed for low-dose ranges typical for single-fraction doses often used in external photon beam radiotherapy. First, the dosimeters were irradiated in a solid water phantom to establish calibration curves in the dose range from 0.3 to 3 Gy for 6 and 18 MV X-ray beams from a clinical linear accelerator. Next, the dosimeters were placed at various locations in an anthropomorphic pelvic phantom to measure the dose delivery of a conventional four-field box technique treatment plan to the pelvis. Finally, the doses measured with alanine dosimeters were compared against the doses calculated with a commercial treatment planning system (TPS). The results showed that the alanine dosimeters have a highly sensitive dose response with good linearity and no energy dependence in the dose range and photon beams used in this work. Also, a fairly good agreement was found between the in-phantom dose measurements with alanine dosimeters and the TPS dose calculations. The mean value of the ratios of measured to calculated dose values was found to be near unity. The measured points in the in-field region passed dose-difference acceptance criterion of 3% and those in the penumbral region passed distance-to-agreement acceptance criterion of 3 mm. These findings suggest that the pure alanine powder in PMMA tube dosimeter is a suitable option for dosimetry of radiotherapy photon beams.
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Affiliation(s)
- Anan M Al-Karmi
- Department of Physics, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
| | - Ali Asghar H Ayaz
- Department of Physics, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
| | - Mamdouh S Al-Enezi
- Department of Physics, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
| | - Wamied Abdel-Rahman
- Department of Radiation Oncology, King Fahad Specialist Hospital - Dammam, Dammam, Saudi Arabia.
| | - Nidal Dwaikat
- Department of Physics, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
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A system for remote dosimetry audit of 3D-CRT, IMRT and VMAT based on lithium formate dosimetry. Radiother Oncol 2014; 113:279-82. [DOI: 10.1016/j.radonc.2014.11.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 11/18/2022]
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Baffa O, Kinoshita A. Clinical applications of alanine/electron spin resonance dosimetry. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2014; 53:233-240. [PMID: 24398918 DOI: 10.1007/s00411-013-0509-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 12/22/2013] [Indexed: 06/03/2023]
Abstract
This paper discusses the clinical applications of electron spin resonance (ESR) dosimetry focusing on the ESR/alanine system. A review of few past studies in this area is presented offering a critical overview of the challenges and opportunities for extending this system into clinical applications. Alanine/ESR dosimetry fulfills many of the required properties for several clinical applications such as water-equivalent composition, independence of the sensitivity for the energy range used in therapy and high precision. Improvements in sensitivity and the development of minidosimeters coupled with the use of a spectrometer of higher microwave frequency expanded the possibilities for clinical applications to the new modalities of radiotherapy (intensity-modulated radiation therapy and radiosurgery) and to the detection of low doses such as those present in some radiological image procedures.
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Affiliation(s)
- Oswaldo Baffa
- Departamento de Física, Faculdade de Filosofia Ciências e Letras, USP, Av. Bandeirantes, 3900, Ribeirão Prêto, SP, 14040-901, Brazil,
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11
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The investigation of lithium formate hydrate, sodium dithionate and N-methyl taurine as clinical EPR dosimeters. RADIAT MEAS 2013. [DOI: 10.1016/j.radmeas.2013.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Anton M, Kapsch RP, Krauss A, von Voigts-Rhetz P, Zink K, McEwen M. Difference in the relative response of the alanine dosimeter to megavoltage x-ray and electron beams. Phys Med Biol 2013; 58:3259-82. [DOI: 10.1088/0031-9155/58/10/3259] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Oraei M, Motallebi A, Hoseini E, Javan S. Effect of gamma irradiation and frozen storage on chemical and sensory characteristics of rainbow trout (Oncorhynchus mykiss) fillet. Int J Food Sci Technol 2012. [DOI: 10.1111/j.1365-2621.2011.02930.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Marrale M, Longo A, Spanò M, Bartolotta A, D'Oca MC, Brai M. Sensitivity of Alanine Dosimeters with Gadolinium Exposed to 6 MV Photons at Clinical Doses. Radiat Res 2011; 176:821-6. [DOI: 10.1667/rr2256.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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15
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A methodology for choosing parameters for ESR readout of alanine dosimeters for radiotherapy. Radiat Phys Chem Oxf Engl 1993 2009. [DOI: 10.1016/j.radphyschem.2009.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Popoca R, Ureña-Núñez F. Dosimetric evaluation of lithium carbonate (Li2CO3) as a dosemeter for gamma-radiation dose measurements. RADIATION PROTECTION DOSIMETRY 2009; 134:102-106. [PMID: 19470449 DOI: 10.1093/rpd/ncp015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This work reports the possibility of using lithium carbonate as a dosimetric material for gamma-radiation measurements. Carboxi-radical ions, CO(2)(-) and CO(3)(-), arise from the gamma irradiation of Li(2)CO(3), and these radical ions can be quantified by electron paramagnetic resonance (EPR) spectrometry. The EPR-signal response of gamma-irradiated lithium carbonate has been investigated to determine some dosimetric characteristics such as: peak-to-peak signal intensity versus gamma dose received, zero-dose response, signal fading, signal repeatability, batch homogeneity, dose rate effect and stability at different environmental conditions. Using the conventional peak-to-peak method of stable ion radicals, it is concluded that lithium carbonate could be used as a gamma dosemeter in the range of 3-100 Gy.
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Affiliation(s)
- R Popoca
- Facultad de Medicina, Universidad Autónoma del Estado de México, Paseo Tollocan S/N, CP 50180, Toluca Edo. de México, México
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17
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Begnozzi L, Benassi M, Bertanelli M, Bonini A, Cionini L, Conte L, Fiorino C, Gabriele P, Gardani G, Giani A, Magri S, Morelli M, Morrica B, Olmi P, Orecchia R, Penduzzu G, Raffaele L, Rosi A, Tabocchini MA, Valdagni R, Viti V. Quality assurance of 3D-CRT: Indications and difficulties in their applications. Crit Rev Oncol Hematol 2009; 70:24-38. [DOI: 10.1016/j.critrevonc.2008.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 06/12/2008] [Accepted: 07/18/2008] [Indexed: 12/25/2022] Open
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19
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Abrego FC, Calcina CSG, de Almeida A, de Almeida CE, Baffa O. Relative output factor and beam profile measurements of small radiation fields with an L-alanine/K-Band EPR minidosimeter. Med Phys 2007; 34:1573-82. [PMID: 17555239 DOI: 10.1118/1.2717414] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The performance of an L-alanine dosimeter with millimeter dimensions was evaluated for dosimetry in small radiation fields. Relative output factor (ROF) measurements were made for 0.5 x 0.5, 1 x 1, 3 x 3, 5 x 5, 10 x 10 cm(2) square fields and for 5-, 10-, 20-, 40-mm-diam circular fields. In beam profile (BP) measurements, only 1 x 1, 3 x 3, 5 x 5 cm2 square fields and 10-, 20-, 40-mm-diam circular fields were used. For square and circular field irradiations, Varian/Clinac 2100, and a Siemens/Mevatron 6 MV linear accelerators were used, respectively. For a batch of 800 L-alanine minidosimeters (miniALAs) the average mass was 4.3+/-0.5 (1 sigma) mg, the diameter was 1.22+/-0.07 (1 sigma) mm, and the length was 3.5+/-0.2 (l sigma) mm. A K-Band (24 GHz) electron paramagnetic resonance (EPR) spectrometer was used for recording the spectrum of irradiated and nonirradiated miniALAs. To evaluate the performance of the miniALAs, their ROF and BP results were compared with those of other types of detectors, such as an ionization chamber (PTW 0.125 cc), a miniTLD (LiF: Mg,Cu,P), and Kodak/X-Omat V radiographic film. Compared to other dosimeters, the ROF results for miniALA show differences of up to 3% for the smallest fields and 7% for the largest ones. These differences were within the miniALA experimental uncertainty (-5-6% at 1 sigma). For BP measurements, the maximum penumbra width difference observed between miniALA and film (10%-90% width) was less than 1 mm for square fields and within 1-2 mm for circular fields. These penumbra width results indicate that the spatial resolution of the miniALA is comparable to that of radiographic film and its dimensions are adequate for the field sizes used in this experiment. The K-Band EPR spectrometer provided adequate sensitivity for assessment of miniALAs with doses of the order of tens of Grays, making this dosimetry system (K-Band/miniALA) a potential candidate for use in radiosurgery dosimetry.
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Affiliation(s)
- Felipe Chen Abrego
- Department of Physics and Mathematics, FFCLRP-University of São Paulo, 14040-901, Ribeirão Preto-SP, Brazil
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Malinen E, Waldeland E, Hole EO, Sagstuen E. LET effects following neutron irradiation of lithium formate EPR dosimeters. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 63:861-9. [PMID: 16495132 DOI: 10.1016/j.saa.2005.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 09/23/2005] [Accepted: 10/01/2005] [Indexed: 05/06/2023]
Abstract
Lithium formate electron paramagnetic resonance (EPR) dosimeters were irradiated using 60Co gamma-rays or fast neutrons to doses ranging from 5 to 20 Gy and investigated by EPR spectroscopy. Using a polynomial fitting procedure in order to accurately analyze peak-to-peak line widths of first derivative EPR spectra, dosimeters irradiated with neutrons had on average 4.4+/-0.9% broader EPR resonance lines than gamma-irradiated dosimeters. The increase in line width was slightly asymmetrical. Computer simulated first derivative polycrystalline EPR spectra of a *CO2- radical gave very good reconstructions of experimental spectra of irradiated dosimeters. The spectrum simulations could then be used as a tool to investigate the line broadening observed following neutron irradiation. It was shown that an increase in the simulated Lorentzian line width could explain both the observed line broadening and the asymmetrical effect. The ratio of the peak-to-peak amplitude of first derivative EPR spectra obtained at two different microwave powers (20 and 0.5 mW) was 7.8+/-1.2% higher for dosimeters irradiated with neutrons. The dependence of the spectrum amplitude on the microwave power was extensively investigated by fitting observations to an analytical non-linear model incorporating, among others, the spin-lattice (T1) and spin-spin (T2) relaxation times as fitting parameters. Neutron irradiation resulted in a reduction in T(2) in comparison with gamma-irradiation, while a smaller difference in T1 was found. The effects observed indicate increased local radical density following irradiation using high linear energy transfer (LET) neutrons as compared to low LET gamma-irradiation. A fingerprint of the LET may thus be found either by an analysis of the line width or of the dependence of the spectrum amplitude on the microwave power. Lithium formate is therefore a promising material for EPR dosimetry of high LET radiation.
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Affiliation(s)
- Eirik Malinen
- Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo, Norway.
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Onori S, Bortolin E, Calicchia A, Carosi A, De Angelis C, Grande S. Use of commercial alanine and TL dosemeters for dosimetry intercomparisons among Italian radiotherapy centres. RADIATION PROTECTION DOSIMETRY 2006; 120:226-9. [PMID: 16644956 DOI: 10.1093/rpd/nci632] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In the implementation of a large-scale dosimetry intercomparison one of the main constraints is the availability of large number of dosemeters of the highest quality. Therefore, ISS tested the possibility of using commercially available dosemeters, alanine pellets and thermoluminescence (TL) dosimetry chips, for transfer dosimetry within the Italian intercomparison programme. In this work the characterisation of commercial alanine and TL dosemeters along with the ISS dose assessment procedure used in the Italian intercomparison are reported. Results demonstrate the feasibility of the ISS approach to transfer dosimetry since it is possible to measure 10 Gy with a combined uncertainty of 1% (1sigma) and 1 Gy with a combined uncertainty of 1.7% (1sigma) with alanine and TL dosemeters, respectively.
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Affiliation(s)
- S Onori
- Department of Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
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22
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Abstract
ESR spectroscopy is currently taking root as a key technology in dosimetry, dating and imaging. In dosimetry, it competes with cytometry in the fields of biological dosimetry and retrospective dosimetry, leads in high-level reference and routine dosimetry, is high-ranking among the methods to identify radiation preserved foods, represents a method of choice to date geological, archaeological and paleontological materials back millions of years, and has demonstrated capacity for imaging. Further scientific and technological progress as predicted in the recent past (Appl. Radiat. Isot. 52 (2000) 1023) is reviewed here. Additionally, the review is expanded to include international reports and recommendations on ESR dosimetry and dose reconstruction, under way at the American Society for Testing and Materials (ASTM), the International Organisation of Standards (ISO), the International Atomic Energy Agency (IAEA) and the International Commission on Radiation Units and Measurements (ICRU). Emphasis is placed on interpretation of tooth enamel doses in terms of organ and effective doses, using CT-based virtual humans. The future of EPR spectroscopy for in situ dose measurements is noted, depicting a non-destructive in vivo dosimetry applicable directly to individuals, but also to hominid and animal fossils for direct dating.
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Affiliation(s)
- Dieter F Regulla
- GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
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