Dosimetric evaluation of newly developed well-type ionization chamber for use in the calibration of brachytherapy sources

Sathiyan, S; Godson, Henry Finlay; Ponmalar, Retna; Ravikumar, M; Mazarello, James

doi:10.4103/0971-6203.195187

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…Evaluation of measurement uncertainty based on the uncertainty component mentioned above obtained an expanded uncertainty of ±3.0%. Based on the uncertainty range obtained for determination of acceptable air Kerma strength was 5%, while the acceptable accuracy of calibration results was ±3% of air Kerma strength measured by the manufacturer [32].…”

Section: Uncertainty Of Measurementmentioning

confidence: 92%

Evaluation of Well-Type Chamber Calibration Factor for Measurement of Ir-192 Brachytherapy Source Over 10 Institutions

Firmansyah

Sunaryati

et al. 2020

JFA

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This paper describes the evaluation of well-type chamber calibration factor for measurement Ir-192 brachytherapy source. Data were collected at ten institutions of Ir-192 brachytherapy facilities. Calibration was carried out using the substitution method adopted from a protocol published by the International Atomic Energy Agency. The well-type chamber standard used was HDR-1000 Plus. The results obtained that NAKS for well-type chamber from PTW manufacturers has a range of values from 9.063 × 10 5 -9.875 × 10 5 Gy m 2 h −1 A −1 with an average value 9.522 × 10 5 Gy m 2 h −1 A −1 , while the well-type chamber from Standard Imaging manufacturers has a range of values from 4.634 × 10 5 -4.662 × 10 5 Gy m 2 h −1 A −1 with an average value 4.648 × 10 5 Gy m 2 h −1 A −1 . The range of deviations obtained between NAKS−new and N AKS−old ranges from 0.8% to -1.8%, while the range of normalization results of NAKS−new to the average value of NAKS−new ranges from 0.952-1.029. There was one calibration factor that has a deviation of more than 1% over the N AKS−old . Based on the calculation of uncertainty, all the calibration factor results obtained were still within the accepted range.

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Section: Uncertainty Of Measurementmentioning

confidence: 92%

Evaluation of Well-Type Chamber Calibration Factor for Measurement of Ir-192 Brachytherapy Source Over 10 Institutions

Firmansyah

Sunaryati

et al. 2020

JFA

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“…Some publications [18][19][20] state that to calculate kscatt can use the 7 distance method published by Goestch et al [21]. The 7 distance method uses an ionization chamber to measure the charge reading at several distances.…”

Section: Free-in-air Measurement Methodsmentioning

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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“…Another important issue observed in inspections is related to well chambers used for dose control of equipment of HDR brachytherapy [24,25]. Different to thimble ion chambers, the sole calibration laboratory for well chambers only started its activities in 2014, roughly at the same time the regulatory body changed the guidelines to include the need of calibration for this kind of dosimeter.…”

Section: Conventional Radiation Therapymentioning

confidence: 99%

Ion chambers compliance results of Brazilian radiation therapy facilities

et al. 2018

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The Brazilian Nuclear Energy Commission (cnen) has been making a constant effort to keep up to date with international standards and national needs to strengthen the status of radiological protection of the country. The guidelines related to radiation therapy facilities have been revised in the last five years in order to take into consideration the most relevant aspects of the growing technology as well as to mitigate the accidents or incidents observed in practice. Hence, clinical dosimeters have gained special importance in this matter. In the present work, we discuss the effectiveness of regulation and inspections to the enforcement of instrument calibration accuracy for the improvement of patient dosimetry and quality control. As a result, we observed that the number of calibrated instruments, mainly well chambers, is increasing each year. The same behavior is observed for instruments employed in technologically advanced radiation treatments such as intensity modulated radiotherapy, volumetric therapy and stereotatic radiosurgery. We ascribe this behavior to the new regulation.

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Dosimetric evaluation of newly developed well-type ionization chamber for use in the calibration of brachytherapy sources

Cited by 5 publications

References 12 publications

Evaluation of Well-Type Chamber Calibration Factor for Measurement of Ir-192 Brachytherapy Source Over 10 Institutions

Evaluation of Well-Type Chamber Calibration Factor for Measurement of Ir-192 Brachytherapy Source Over 10 Institutions

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

Ion chambers compliance results of Brazilian radiation therapy facilities

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