Calibration of a Microselectron HDR iridium 192 source

Flynn, Anthony; Workman, G.

doi:10.1259/0007-1285-64-764-734

Cited by 10 publications

(4 citation statements)

References 3 publications

(2 reference statements)

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“…Some studies use a calibration factor from irradiation with 60 Co (Kapp et al 1992, Pradhan andQuast 2000) or a 300 kVp clinical orthovoltage therapy beam (Howlett et al 1996, Duggan et al 2000. For example, Flynn and Workman (1991) discussed the problems involved in measuring the air kerma rate at 5 cm from low dose rate (LDR) and HDR 192 Ir brachytherapy sources, such as the steep dose gradient, electrometer leakage over long exposure times for ionization chambers (for LDR sources) and that it would be preferable to have a calibration factor for the relevant photon energy traceable to a standard rather than using a factor for 60 Co. Furthermore, Mangold et al (2001) stated that the limited accuracy of source strength specification of 192 Ir is a possible source of a systematic error in the treatment planning calculation since it is an essential input parameter.…”

Section: Diagnostic and Interventional Radiologymentioning

confidence: 99%

Variations in dose response with x-ray energy of LiF:Mg,Cu,P thermoluminescence dosimeters: implications for clinical dosimetry

et al. 2004

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In many medical procedures where accurate radiation dose measurements are needed, the variation of detector response with x-ray energy is of concern. The response of LiF:Mg,Cu,P TLDs to a range of x-ray energies was analysed in monoenergetic (synchrotron), diagnostic and therapy radiation beams with the aim of implementing this dosimeter into clinical practice where existing dosimetry techniques are limited due to lack of sensitivity or tissue equivalence (e.g. neonatal radiography, mammography and brachytherapy). LiF:Mg,Cu,P TLDs in different forms from two manufacturers (MCP-N: TLD Poland, GR200: SDDML China) were irradiated using x-ray beams covering 10 keV to 18 MVp. Dose readings were compared with an ionization chamber. The effect of different TLD types and annealing cycles on clinical utility was investigated. The measured energy response of LiF:Mg,Cu,P TLDs was fit to a simple model devised by Kron et al (1998 Phys. Med. Biol. 43 3235-59) to describe the variation of TLD response with x-ray energy. If TLDs are handled as recommended in the present paper, the energy response of LiF:Mg,Cu,P deviates by a maximum of 15% from unity and agrees with the model to within 5% or experimental uncertainty between 15 keV and 10 MeV. LiF:Mg,Cu,P TLDs of all forms have consistent and superior energy response compared to the standard material LiF:Mg,Ti and are therefore suitable for a wide range of applications in diagnostic radiology and radiotherapy.

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Section: Diagnostic and Interventional Radiologymentioning

confidence: 99%

Variations in dose response with x-ray energy of LiF:Mg,Cu,P thermoluminescence dosimeters: implications for clinical dosimetry

et al. 2004

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“…Source calibration has received much attention from medical physicists and the medical literature contains many discussions about its technical aspects (Flynn and 161 NuREG/CR-6 125 Workman, 1991;Goetsch et al, 1991;Kohn, Gooch, and Zajac, 1991;Meertens, 1990;Wu et al, 1990). Problems have been reported that have implicated inaccurate supplier source calibration data.…”

Section: Quality Assurance and Maintenancementioning

confidence: 99%

Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

Callan¹,

Kelly²,

Quinn³

1995

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“…The calibration of an Ir-192 HDR system using the Farmer chamber has been studied for decades [ 8 – 12 ]. The standard AKS calibration for Ir-192 sources was established at the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) in 1991 by Goetsch et al [ 9 ], who employed an interpolation procedure using NIST calibrations of 662 keV (Cs-137) and 146 keV (250 kVcp X-rays) to get a calibration of 397 keV (the exposure-weighted average Ir-192 energy) because NIST does not offer calibration of ionization chambers with the gamma-ray spectrum of Ir-192.…”

Section: Introductionmentioning

confidence: 99%

Ir-192 Calibration in Air with Farmer Chamber for HDR Brachytherapy

Chang

Lee

et al. 2016

J. Med. Biol. Eng.

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A comprehensive review for the in-air calibration of an Ir-192 high-dose-rate brachytherapy source in terms of air kerma strength (AKS) and reference air kerma rate (RAKR) using the Farmer chamber was conducted. The reviewed calibration methods include the National Physical Laboratory (NPL) calibration standard in the UK, the 7-distance technique with the standard calibration of the National Institute of Standards and Technology and Accredited Dosimetry Calibration Laboratory in the US, the calibration conducted in Australia following recommendations of the International Atomic Energy Agency with the chamber primarily calibrated by the Australian Radiation Protection and Nuclear Safety Agency, the calibration conducted in India following the Deutsche Gesellschaft fur Medizinische Physik recommendation, and the convenient empirical method used in Taiwan. The calibrated AKS (or RAKR) and uncertainty obtained using Farmer chambers are similar to those obtained using well chambers. All reported differences (between measurements obtained using Farmer and well chambers, respectively) and uncertainties (k = 2) were generally less than 1.5 and 2.5 %, respectively. The standard uncertainty of the NPL calibration is approximately half that of all the other proposed approaches, and may become the gold standard calibration procedure. Almost all techniques follow the 7-distance technique basis; however, the services at NPL can calibrate the source with lower uncertainty. Users can calibrate the Ir-192 source more conveniently using the empirical method with only one source-chamber distance.

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Calibration of a Microselectron HDR iridium 192 source

Cited by 10 publications

References 3 publications

Variations in dose response with x-ray energy of LiF:Mg,Cu,P thermoluminescence dosimeters: implications for clinical dosimetry

Variations in dose response with x-ray energy of LiF:Mg,Cu,P thermoluminescence dosimeters: implications for clinical dosimetry

Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

Ir-192 Calibration in Air with Farmer Chamber for HDR Brachytherapy

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