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Madden L, Lukas E, Santos A, Ganija M, Veitch P, Rosenfeld A, Li E. Deconvolution analysis improves real-time OSL of BeO ceramic. RADIAT MEAS 2021. [DOI: 10.1016/j.radmeas.2021.106680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Madden L, Santos A, Li E, Gowda R, Bezak E, Afshar V S, Rosenfeld A. Temporal modelling of beryllium oxide ceramics' real-time OSL for dosimetry with a superficial 140 kVp X-ray beam. Phys Med 2020; 80:17-22. [PMID: 33070008 DOI: 10.1016/j.ejmp.2020.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/17/2020] [Accepted: 10/03/2020] [Indexed: 11/30/2022] Open
Abstract
A new analysis method for the rtOSL of BeO ceramics is presented, using temporal curve fitting of an expected rtOSL signal to measured rtOSL signals. The presented technique does not require heavy signal averaging to determine the OSL bleaching correction associated with the ΔrtOSL method, reducing uncertainties in the post-correction rtOSL. The corrected rtOSL signal was demonstrated to be linear with dose, and dose-rate independent. The presented technique is expected to be applicable for many other dosimeters capable of the rtOSL technique. The presented technique achieved relative uncertainties in the corrected rtOSL between 3.4% and 6.5%. The initial measurements are promising, but uncertainties are required to be further improved upon before the technique can be used clinically.
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Affiliation(s)
- Levi Madden
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia
| | - Alexandre Santos
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia; School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Enbang Li
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia.
| | - Raghu Gowda
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia
| | - Eva Bezak
- School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia; Cancer Research Institute and the School of Health Sciences, University of South Australia, Adelaide, South Australia 5001, Australia
| | - Shahraam Afshar V
- School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia; Division of Information Technology, Engineering and Environment, School of Engineering, The University of South Australia, Adelaide, South Australia 5000, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, NSW 2522, Australia; Illawarra Medical and Health Research Institute, University of Wollongong, NSW 2522, Australia
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Schuyt JJ, Donaldson J, Williams GVM, Chong SV. Modelling the radioluminescence of Sm 2+ and Sm 3+ in the dosimeter material NaMgF 3:Sm. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:025703. [PMID: 31530766 DOI: 10.1088/1361-648x/ab450d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Photoluminescence (PL) and radioluminescence (RL) measurements were made on NaMgF3:Sm before, during and after exposure to high doses of ionising radiation. Magnetic measurements prior to irradiation showed that approximately 10% of the total Sm concentration was in the divalent state. The RL from Sm3+ was found to increase while the Sm2+ RL decreased with increasing x-ray dose before reaching steady-state values for high doses. This behaviour is opposite to that previously reported for Sm3+ and Sm2+ PL. We show that this apparent discrepancy can be accounted for by a RL model where there is a hole trap, an electron trap, and direct x-ray induced carrier recombination at Sm2+ and Sm3+. Furthermore, a good fit to the dose-dependence of all of the Sm RL emissions can be obtained by assuming that the relevant electron and hole traps are close to Sm3+. Our model accounts for F3-centre production during irradiation that affects some of the Sm3+ RL emissions via reabsorption of the RL by the F3-centres. Thus, the rate of F3-centre production can be conveniently monitored by the RL intensity ratio, I RL(567 nm)/I RL(650 nm). Additionally, the Sm2+ RL emissions may be expressed as [1.94 × I RL(721 nm)] - I RL(695 nm) to determine the real-time dose rate, independent of dose history.
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Affiliation(s)
- J J Schuyt
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
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Santos AMC, Gowda R, Bezak E, Afshar V S. Evaluation of a real-time optically stimulated luminescence beryllium oxide (BeO) fibre-coupled dosimetry system with a superficial 140 kVp X-ray beam. Phys Med 2019; 65:167-171. [PMID: 31494370 DOI: 10.1016/j.ejmp.2019.08.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 06/18/2019] [Accepted: 08/29/2019] [Indexed: 11/16/2022] Open
Abstract
The purpose of this study was to investigate the potential of real-time optically stimulated luminescence (rtOSL) measurements of a beryllium oxide (BeO) ceramic fibre-coupled luminescence dosimetry system. By pulsing the stimulation laser during the exposure to ionizing radiation, an rtOSL dose-rate measurement can be obtained which could be stem effect free. A portable rtOSL BeO ceramic fibre-coupled dosimetry system is presented and characterized using a constant dose-rate superficial 140 kVp X-ray beam. The rtOSL was measured for dose-rates between 0.29 and 3.88 Gy/min, controlled by varying the source to surface distance. After correcting for OSL decay during the exposure, a linear dose-rate response of the change in rtOSL (ΔrtOSL) was observed. The ΔrtOSL was also observed to be stem effect free.
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Affiliation(s)
- Alexandre M Caraça Santos
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia; School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Raghu Gowda
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia
| | - Eva Bezak
- School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia; Cancer Research Institute and the School of Health Sciences, University of South Australia, Adelaide, South Australia 5001, Australia
| | - Shahraam Afshar V
- School of Physical Sciences and Institute for Photonics and Advanced Sensing, University of Adelaide, Adelaide, South Australia 5005, Australia; Division of Information Technology, Engineering and Environment, School of Engineering, The University of South Australia, Adelaide, South Australia 5000, Australia
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Teichmann T, Sponner J, Henniger J. Fiber optical dose rate measurement based on the luminescence of beryllium oxide. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201817009012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This work presents a fiber optical dose rate measurement system based on the radioluminescence and optically stimulated luminescence of beryllium oxide. The system consists of a small, radiation sensitive probe which is coupled to a light detection unit with a long and flexible light guide. Exposing the beryllium oxide probe to ionizing radiation results in the emission of light with an intensity which is proportional to the dose rate. Additionally, optically stimulated luminescence can be used to obtain dose and dose rate information during irradiation or retrospectively. The system is capable of real time dose rate measurements in fields of high dose rates and dose rate gradients and in complex, narrow geometries. This enables the application for radiation protection measurements as well as for quality control in radiotherapy. One inherent drawback of fiber optical dosimetry systems is the generation of Cherenkov radiation and luminescence in the light guide itself when it is exposed to ionizing radiation. This so called “stem” effect leads to an additional signal which introduces a deviation in the dose rate measurement and reduces the spatial resolution of the system, hence it has to be removed. The current system uses temporal discrimination of the effect for radioluminescence measurements in pulsed radiation fields and modulated optically stimulated luminescence for continuous irradiation conditions. This work gives an overview of the major results and discusses new-found obstacles of the applied methods of stem discrimination.
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Study of dosimetric characteristics of a commercial optically stimulated luminescence system. JOURNAL OF RADIOTHERAPY IN PRACTICE 2017. [DOI: 10.1017/s1460396917000346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractBackgroundOptically stimulated luminescence dosimeters (OSLDs) have a number of advantages in radiation dosimetry making them an excellent dosimeter for in vivo dosimetry. The study aimed to study the dosimetric characteristics of a commercial optically stimulated luminescence (OSL) system by Landauer Inc., before using it for routine clinical practice for in vivo dosimetry in radiotherapy. Further, this study also aimed to investigate the cause of variability found in the literature in a few dosimetric parameters of carbon-doped aluminium oxide (Al2O3:C).Materials and methodsThe commercial OSLD system uses Al2O3:C nanoDotTM as an active radiation detector and InLightTM microStar® as a readout assembly. Inter-detector response, energy, dose rate, field size and depth dependency of the detector response were evaluated for all available clinical range of photon beam energies in radiotherapy.ResultsInter-detector variation in OSLD response was found within 3·44%. After single light exposure for the OSL readout, detector reading decreased by 0·29% per reading. The dose linearity was investigated between dose range 50–400 cGy. The dose response curve was found to be linear until 250 cGy, after this dose, the dose response curve was found to be supra-linear in nature. OSLD response was found to be energy independent for Co60 to 10 MV photon energies.ConclusionsThe cause of variability found in the literature for some dosimetric characteristics of Al2O3:C is due to the difference in general geometry, construction of dosimeter, geometric condition of irradiation, phantom material and geometry, beam energy. In addition, the irradiation history of detector used and difference in readout methodologies had varying degree of uncertainties in measurements. However, the large surface area of the detector placed in the phantom with sufficient build-up and backscatter irradiated perpendicularly to incident radiation in Co60 beam is a good method of choice for the calibration of a dosimeter. Understanding the OSLD response with all dosimetric parameters may help us in estimation of accurate dose delivered to patient during radiotherapy treatment.
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Dhabekar B, Rawat N, Gaikwad N, Kadam S, Koul D. Dosimetric characterization of highly sensitive OSL phosphor: LiCaAlF6:Eu,Y. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Le Guillou M, Gruel A, Destouches C, Blaise P. State of the art on nuclear heating measurement methods and expected improvements in zero power research reactors. EPJ NUCLEAR SCIENCES & TECHNOLOGIES 2017. [DOI: 10.1051/epjn/2017002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Real time dose rate measurements with fiber optic probes based on the RL and OSL of beryllium oxide. RADIAT MEAS 2016. [DOI: 10.1016/j.radmeas.2016.01.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Liu PZY, Suchowerska N, McKenzie DR. Twisted pair of optic fibers for background removal in radiation fields. APPLIED OPTICS 2013; 52:5500-5507. [PMID: 23913071 DOI: 10.1364/ao.52.005500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/02/2013] [Indexed: 06/02/2023]
Abstract
In many situations in which an optic fiber carries a signal through a radiation field, an unwanted background signal is produced consisting of fluorescent and/or Cerenkov light. This presents a major problem in the measurement of the light signal, for example, in scintillation dosimetry of medical therapeutic beams. In this paper, we demonstrate a new method of measuring and removing the background signal through the use of a twisted pair of optic fibers. The twisted pair consists of a fiber carrying the scintillation signal that is twisted with a second optic fiber to form a double helix. The two twisted fibers will experience the same radiation environment provided the periodicity of the twist is correlated to the dose rate gradient. An expression for the required twist periodicity is presented. A scintillation dosimeter with a twisted pair optic fiber was tested in a megavoltage beam and found to accurately measure its beam characteristics. The twisted pair approach is not restricted to medical applications and can be used in many situations in which optical signals are carried through radiation fields.
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Affiliation(s)
- P Z Y Liu
- School of Physics, University of Sydney, New South Wales, Australia.
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Klein D, Briere TM, Kudchadker R, Archambault L, Beaulieu L, Lee A, Beddar S. In-phantom dose verification of prostate IMRT and VMAT deliveries using plastic scintillation detectors. RADIAT MEAS 2012. [PMID: 23180976 DOI: 10.1016/j.radmeas.2012.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The goal of this work was to demonstrate the feasibility of using a plastic scintillation detector (PSD) incorporated into a prostate immobilization device to verify doses in vivo delivered during intensity-modulated radiation therapy (IMRT) and volumetric modulated-arc therapy (VMAT) for prostate cancer. The treatment plans for both modalities had been developed for a patient undergoing prostate radiation therapy. First, a study was performed to test the dependence, if any, of PSD accuracy on the number and type of calibration conditions. This study included PSD measurements of each treatment plan being delivered under quality assurance (QA) conditions using a rigid QA phantom. PSD results obtained under these conditions were compared to ionization chamber measurements. After an optimal set of calibration factors had been found, the PSD was combined with a commercial endorectal balloon used for rectal distension and prostate immobilization during external beam radiotherapy. This PSD-enhanced endorectal balloon was placed inside of a deformable anthropomorphic phantom designed to simulate male pelvic anatomy. PSD results obtained under these so-called "simulated treatment conditions" were compared to doses calculated by the treatment planning system (TPS). With the PSD still inserted in the pelvic phantom, each plan was delivered once again after applying a shift of 1 cm anterior to the original isocenter to simulate a treatment setup error.The mean total accumulated dose measured using the PSD differed the TPS-calculated doses by less than 1% for both treatment modalities simulated treatment conditions using the pelvic phantom. When the isocenter was shifted, the PSD results differed from the TPS calculations of mean dose by 1.2% (for IMRT) and 10.1% (for VMAT); in both cases, the doses were within the dose range calculated over the detector volume for these regions of steep dose gradient. Our results suggest that the system could benefit prostate cancer patient treatment by providing accurate in vivo dose reports during treatment and verify in real-time whether treatments are being delivered according to the prescribed plan.
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Affiliation(s)
- David Klein
- Department of Radiation Physics, Unit 94, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
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Monte-Carlo simulations of Al2O3 dosimetry in uniform MV photon beams: Influence of field and detector size. RADIAT MEAS 2012. [DOI: 10.1016/j.radmeas.2012.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Mrčela I, Bokulić T, Izewska J, Budanec M, Fröbe A, Kusić Z. Optically stimulated luminescencein vivodosimetry for radiotherapy: physical characterization and clinical measurements in60Co beams. Phys Med Biol 2011; 56:6065-82. [DOI: 10.1088/0031-9155/56/18/018] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tanyi JA, Nitzling KD, Lodwick CJ, Huston AL, Justus BL. Characterization of a gated fiber-optic-coupled detector for application in clinical electron beam dosimetry. Med Phys 2011; 38:961-7. [DOI: 10.1118/1.3539737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Jursinic PA. Changes in optically stimulated luminescent dosimeter (OSLD) dosimetric characteristics with accumulated dose. Med Phys 2009; 37:132-40. [DOI: 10.1118/1.3267489] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Yukihara EG, McKeever SWS. Optically stimulated luminescence (OSL) dosimetry in medicine. Phys Med Biol 2008; 53:R351-79. [DOI: 10.1088/0031-9155/53/20/r01] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Mones E, Veronese I, Vedda A, Loi G, Fasoli M, Moretti F, Chiodini N, Cannillo B, Brambilla M. Ce-doped optical fibre as radioluminescent dosimeter in radiotherapy. RADIAT MEAS 2008. [DOI: 10.1016/j.radmeas.2008.01.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Fernandez AF, Brichard B, O’Keeffe S, Fitzpatrick C, Lewis E, Vaille JR, Dusseau L, Jackson D, Ravotti F, Glaser M, El-Rabii H. Real-time fibre optic radiation dosimeters for nuclear environment monitoring around thermonuclear reactors. FUSION ENGINEERING AND DESIGN 2008. [DOI: 10.1016/j.fusengdes.2007.05.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Jursinic PA. Characterization of optically stimulated luminescent dosimeters, OSLDs, for clinical dosimetric measurements. Med Phys 2007; 34:4594-604. [DOI: 10.1118/1.2804555] [Citation(s) in RCA: 267] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Akselrod M, Bøtter-Jensen L, McKeever S. Optically stimulated luminescence and its use in medical dosimetry. RADIAT MEAS 2006. [DOI: 10.1016/j.radmeas.2007.01.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Andersen CE, Marckmann CJ, Aznar MC, Bøtter-Jensen L, Kjaer-Kristoffersen F, Medin J. An algorithm for real-time dosimetry in intensity-modulated radiation therapy using the radioluminescence signal from Al2O3:C. RADIATION PROTECTION DOSIMETRY 2006; 120:7-13. [PMID: 16644973 DOI: 10.1093/rpd/nci600] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Although the radioluminescence (RL) signal from optical fibre Al(2)O(3):C dosemeters used in medical applications is essentially proportional to dose rate, the crystals used so far are imperfect in the sense that their RL sensitivity changes with accumulated dose. A computational algorithm has been developed that corrects for these sensitivity changes. We further report on a new system that effectively separates the RL signal generated in the crystal from fluorescence and Cerenkov emission generated in the optical fibre cable using a gating technique in connection with pulsed linear accelerator radiation beams. The dosimetry system has been used for dose measurements in a phantom during an intensity-modulated radiation therapy (IMRT) treatment with 6 MV photons. The RL measurement results are in excellent agreement (i.e. within 1%) with both the OSL results and the dose delivered according to the treatment planning system. RL signals from Al(2)O(3):C can be used for real-time dose rate measurements with a time resolution of approximately 0.1 s and a spatial resolution only limited by the size of the detector (<0.5 mm).
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Affiliation(s)
- C E Andersen
- Risø National Laboratory, Radiation Research Department, DK-4000 Roskilde, Denmark.
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Yukihara EG, McKeever SWS. Ionisation density dependence of the optically and thermally stimulated luminescence from Al2O3:C. RADIATION PROTECTION DOSIMETRY 2006; 119:206-17. [PMID: 16585262 DOI: 10.1093/rpd/nci591] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This paper presents an overview of recent results on ionisation density dependence of the thermally stimulated luminescence (TL) and optically stimulated luminescence (OSL) signals from Al2O3:C, with emphasis on the sensitivity, efficiency, shape of the TL/OSL curves and the emission spectrum. High-ionisation densities are created uniformly by accumulated high doses of low-linear energy transfer radiation (gamma, beta, X rays) or non-uniformly in heavy charged particle tracks, even at low fluences, as in the case of space radiation fields. Significant deep trap filling, which occurs at these high-ionisation densities, ultimately results in changes in the concentration of recombination centres (F+-centres) and, consequently, in sensitivity changes and other effects. An OSL emission band at 335 nm has been observed in addition to the main F-centre luminescence band, and the relative intensities of these bands have been observed to be dependent on the ionisation density. The implications of these results and open issues are discussed.
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Affiliation(s)
- Eduardo G Yukihara
- Department of Physics, Oklahoma State University, Stillwater, OK 74078, USA.
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Gaza R, McKeever SWS. A real-time, high-resolution optical fibre dosemeter based on optically stimulated luminescence (OSL) of KBr:Eu, for potential use during the radiotherapy of cancer. RADIATION PROTECTION DOSIMETRY 2006; 120:14-9. [PMID: 16644971 DOI: 10.1093/rpd/nci603] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A real-time optically stimulated luminescence (OSL) dosimetry system for potential in vivo use during radiotherapy treatments is proposed. Single-crystal europium-doped KBr samples were grown in a Bridgman furnace, and characterised using optical absorption techniques. An algorithm for the processing of the OSL signal was defined for use in real-time measurements, and its performance was studied on data obtained with a home-built reader, using optical-fibre-coupled dosemeters. OSL dose-response, fading properties and temperature dependence of the signal were investigated in correlation with the concentration of Eu(2+) dopant in the sample.
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Affiliation(s)
- R Gaza
- Department of Physics, Oklahoma State University, 145 PS II, Stillwater, OK 74078, USA.
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Gaza R, McKeever SWS, Akselrod MS. Near-real-time radiotherapy dosimetry using optically stimulated luminescence of Al2O3:C: Mathematical models and preliminary results. Med Phys 2005; 32:1094-102. [PMID: 15895594 DOI: 10.1118/1.1884365] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this paper we report investigations aimed toward applying optically stimulated luminescence (OSL) of Al2O3:C for near-real-time medical dosimetry, especially in radiotherapy. The classical mathematical model normally used for the description of OSL phenomena was expanded to predict the behavior of the luminescence signal in the case when the OSL sample is simultaneously irradiated and optically stimulated. The predictions obtained were used to develop different measurement approaches and correction algorithms for the luminescence signals, thus enabling dose estimation from OSL during rather then after the irradiation procedure. Radiation probes with diameters of less than 1 mm, suitable for the envisioned in-vivo measurements were constructed by attaching small Al2O3:C crystals to optical fiber cables. The OSL fiber probes and a purpose-built, portable OSL stimulation and readout system were used to measure doses at speeds up to 1 data point every 3s, under irradiation at dose rates of the same order of magnitude as those found in conventional radiotherapy techniques. The corrected OSL signal was found to be proportional to the absorbed dose, and accurately followed sudden transitions in the irradiation dose rate.
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Affiliation(s)
- R Gaza
- Department of Physics, Oklahoma State University, 145 PS II, Stillwater, Oklahoma 74078, USA.
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