Calibration of 192Ir high dose rate brachytherapy source using different calibration procedures

Shwetha, B; Ravikumar, M; Supe, Sanjay S.; Reddy, Buchuppudi Rekha

doi:10.1016/j.rpor.2013.07.014

Cited by 7 publications

(11 citation statements)

References 14 publications

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“…To calibrate the Ir-192 source, two experimental studies that used the DGMP recommendation [ 36 ], a recommendation used in German, were reported by Patel et al and Bondel et al [ 16 , 17 ], respectively. Their Ir-192 calibrations are mainly traced from the Co-60 calibration factor of the absorbed dose to water.…”

Section: Modified Calibration Methods In Indiamentioning

confidence: 99%

“…The calibration method is similar to the 7-distance technique (Eq. 6 ), but the Ir-192 air kerma calibration factor was derived differently: where N k_Ir_DG is the air kerma calibration factor from the recommendation of DGMP; g is the fraction of energy of the secondary electrons lost in bremsstrahlung; s 0.899, the mass energy absorption coefficient of air to that of water for Ir-192; N Co_DW is the calibration factor of the Co-60 absorbed dose to water of the Farmer chamber; K Q is the beam quality correction factor, which accounts for the differences in the energy spectrum of Co-60 for which the chamber has been calibrated and can be determined by interpolation from the energy response curves provided by the supplier or taken as 1.0, since the energy dependence of modern thimble chambers is trivial [ 17 ] (e.g., the difference between the calibration factors at the Cs-137 and 250-kVp X-ray points was approximately 2 % [ 12 ]).…”

Section: Modified Calibration Methods In Indiamentioning

confidence: 99%

“…The one exception is if the calibration is conducted by the National Physical Laboratory (NPL) in the UK; the expended uncertainty of the calibration coefficient obtained using the well chamber (0.8 %) is slightly lower than that obtained using the Farmer chamber/jig combination (1.1 %) [ 3 , 15 ]. In principle, more accurate calibration results can be obtained by using the Farmer chamber compared to those obtained using the well chamber [ 14 , 16 , 17 ].

Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The units of AKS and RAKR have the same physical quantity; the difference between them is that the dose and time units of RAKR are in Gy and seconds [ 3 ]. The 7-distance technique has been combined with other calibration techniques, such as the calibration conducted in Australia by Butler et al [ 18 ] following recommendations of the International Atomic Energy Agency (IAEA) with the chamber primarily calibrated by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), and the calibration conducted in India by Patel et al [ 16 ] and Bondel et al [ 17 ] following the Deutsche Gesellschaft fur Medizinische Physik (DGMP) recommendation.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Modified Calibration Methods In Indiamentioning

confidence: 99%

Section: Modified Calibration Methods In Indiamentioning

confidence: 99%

Fig.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Chang

Lee

et al. 2016

J. Med. Biol. Eng.

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“…Unlike direct measurements in the air, well-type ionization chambers were specifically designed to measure the source of brachytherapy and open to the atmosphere. Well-type chambers were more recommended in measuring the source of the brachytherapy in terms of air Kerma strength (AKS) [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

A Preliminary Study of Radiation Quality Correction Factor (Kq) Determination for Well-Type Ionization Chamber

Firmansyah

Wulandari³

et al. 2020

SPEKTRA

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This paper deals with the determination of the radiation quality correction factor (kQ) well-type ionization chamber for the measurement of Co-60 brachytherapy. The measurement of the brachytherapy source has been done in the hospital brachytherapy facilities. The measurement of air Kerma has been done using three different ionization chambers 0.6 cm3, 30 cm3, 80 cm3, which have calibration factor traceability for Co-60 and one well-type ionization chamber which calibrated for Ir-192. The determination of the radiation quality correction factor (kQ) was determined based on the results of the air Kerma ratio between measurements using ionization chambers, which have traceability to Co-60 and Ir-192 sources. The results of the measurement of the reference air Kerma rate (RAKR) obtained from the three chambers were 21.36, 19.87, 19.34 mGy.m2.h-1, while the results of measurements with ionization chambers get a value of 19.01 mGy.m2.h-1. The kQCal results from 0.6 cm3 ionization chamber get a value of 1.07. The kQCal value was compared with the value of Andreas Schuller’s et al. kQreff of 1.05 and get a deviation of 2.2%. Implementation of the booth kQ value on the results of the RAKR from the HDR1000Plus well-type ionization chamber in the measurement of brachytherapy in two different facilities gets maximal deviation 1.7% with dose value from Treatment Planning System (TPS). The deviation was in the acceptable range of ±5%. Based on this, the use of radiation quality correction factor (kQ) value can be implemented as one method if it does not have the traceability factor calibration of the Co-60 brachytherapy source.

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3D printed brachytherapy jig for Reference Air Kerma Rate calibration

et al. 2021

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3D printing in modern radiotherapy provides creative autonomy which can be a valuable tool for use in brachytherapy source calibration. Radiotherapy centres may verify their brachytherapy source strength with a calibrated Farmer chamber. For this purpose, a jig was designed, 3D printed and commissioned for in-air source strength calibration. Measurements on four afterloaders with varied equipment and environments were completed. A full uncertainty budget was developed and measurements with the in-air jig were consistently within 3% of the certificate source strength. By creating a jig that is able to be customised to multiple catheter sizes and cylindrical chamber designs, centres can be provided with the option of independently checking their source strength with ease and for little cost.

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Calibration of 192Ir high dose rate brachytherapy source using different calibration procedures

Cited by 7 publications

References 14 publications

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

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

A Preliminary Study of Radiation Quality Correction Factor (Kq) Determination for Well-Type Ionization Chamber

3D printed brachytherapy jig for Reference Air Kerma Rate calibration

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