title: Ir-192 Calibration in Air with Farmer Chamber for HDR Brachytherapy.
abstract: 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.
authors.affiliation: Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung, 82445 Taiwan.
authors.forename: Liyun
authors.initials: L
authors.lastname: Chang
authors.affiliation: Department of Nursing, Chang Jung Christian University, Tainan, 71101 Taiwan ; Department of Radiation Oncology, Chi Mei Medical Center, Liouying, Tainan, 73657 Taiwan.
authors.forename: Sheng-Yow
authors.initials: SY
authors.lastname: Ho
authors.affiliation: Medical Physics and Informatics Laboratory, Department of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung, 80778 Taiwan.
authors.forename: Tsair-Fwu
authors.initials: TF
authors.lastname: Lee
authors.affiliation: Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung, 82445 Taiwan.
authors.forename: Hueisch-Jy
authors.initials: HJ
authors.lastname: Ding
authors.affiliation: Department of Radiation Oncology, Sinlau Christian Hospital, Tainan, 70142 Taiwan.
authors.forename: Pang-Yu
authors.initials: PY
authors.lastname: Chen
keywords: Farmer-type ion chamber; High dose rate (HDR); In-air calibration; Ir-192 calibration