Determination of TRS-398 Quality Factors for Cs-137 Gamma Rays in Reference Dosimetry

Kang, Sang Koo; Rhee, Dong Joo; Kang, Yeong Rok; Kim, Jeung Kee; Jeong, Dong Hyeok

doi:10.14316/pmp.2014.25.3.123

Cited by 2 publications

(1 citation statement)

References 4 publications

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“…According to the recent international protocols, 137 Cs is used as a good beam quality for calibration in the range of radiation protection [6][7][8][9][10]. 137 Cs reference beam at NIS is characterized to be used in survey meter calibrations and other radiation detectors at protection level as well.…”

Section: Introductionmentioning

confidence: 99%

Development of ¹³⁷Cs irradiation facility for metrological application

Hassan

Esmat

El-Sersy

2017

Int. J. Metrol. Qual. Eng.

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Abstract. In this work, 137 Cs irradiation facility at the National Institute of Standards (NIS) was developed to enhance the calibration processes. Different thickness lead sheets were used for beam attenuation, to enlarge the 137 Cs dose range. Ambient dose equivalent rate, H*(10) was measured using two ionization chambers at a different source-detector distances (SDDs) and a lead sheet thickness. The deviation from the inverse square law for the dose-SDD relationship was obtained. The beam flatness of unattenuated and the lead attenuated beam was measured. The attenuation coefficient for the used lead sheets was obtained and correlated to the broad beam geometry. The room scattering was studied in detail. The uncertainty of the measured doses was calculated. It was found that the inverse square law is verified well at SDD ≥ 2 m. The measured attenuation coefficient for lead attenuators is affected by the broad beam geometry. The contribution of the scattering component of the dose at a certain SDD is the major source of uncertainty since it extracted a value of 1.05%, while the combined uncertainty from all other factors affecting the dose measurements is 1.34%.

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Section: Introductionmentioning

confidence: 99%

Development of ¹³⁷Cs irradiation facility for metrological application

Hassan

Esmat

El-Sersy

2017

Int. J. Metrol. Qual. Eng.

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Uncertainties Associated with Clonogenic Assays using a Cs-137 Irradiator and Ir-192 Afterloader: A Comprehensive Compilation for Radiation Researchers

et al. 2022

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Clonogenic assays are the gold standard for measuring cell clonogenic survival and enable quantification of a cell line's radiosensitivity through the calculation of the surviving fraction, the ratio of cell clusters (colonies) formed after radiation exposure compared to the number formed without exposure. Such studies regularly utilize Cs-137 irradiators. While uncertainties for specific procedural aspects have been described previously, a comprehensive review has not been completed. We therefore quantified uncertainties associated with clonogenic assays performed using a Cs-137 Shepherd irradiator, and a recently established brachytherapy afterloader in vitro radiation delivery apparatus (BAIRDA), through a series of experiments and a literature review. The clonogenic assay is subject to uncertainties that affect the determination of the surviving fraction (e.g., accuracy of the number of cells seeded, potential effects of hypothermia, and the threshold number of cells for a cluster to be identified as a colony). Furthermore, dose delivery uncertainties related to both the Cs-137 irradiator and BAIRDA were also quantified. The combined standard (k = 1) uncertainty was ± 6.0% in the surviving fraction for the Cs-137 irradiator (±6.3% for BAIRDA), up to ± 1.3% in the dose delivered by the Cs-137 irradiator, and up to ± 2.2% in the dose delivered by BAIRDA. The largest individual uncertainties were associated with the number of cells seeded on a plate (3.4%) and inter-observer variability in counting (4.1%), suggesting that effective reduction of uncertainties in the conduct of the clonogenic assay proper may provide the greatest relief on the uncertainty budget. Finally, measurable impact on experimental findings was assessed by applying this uncertainty to clonogenic assays of SW756 cells using either a Cs-137 irradiator or BAIRDA, introducing a maximum shift in the reported radiobiological parameters a/b and T1/2 of 0.3 Gy and 0.4 h, respectively, while the 95% confidence interval increased by 0.5 Gy and decreased by 0.4 h, respectively. Though the overall impact on radiobiological parameter estimation was small, the individual uncertainties could have a significant influence in other applications of in vitro experiments in radiation biology. Hence, better understanding of the uncertainties associated with both clonogenic assays and the radiation source used can improve the accuracy of experimental analysis and reproducibility of the results.

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Determination of TRS-398 Quality Factors for Cs-137 Gamma Rays in Reference Dosimetry

Cited by 2 publications

References 4 publications

Development of ¹³⁷Cs irradiation facility for metrological application

Development of ¹³⁷Cs irradiation facility for metrological application

Uncertainties Associated with Clonogenic Assays using a Cs-137 Irradiator and Ir-192 Afterloader: A Comprehensive Compilation for Radiation Researchers

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Determination of TRS-398 Quality Factors for Cs-137 Gamma Rays in Reference Dosimetry

Cited by 2 publications

References 4 publications

Development of 137Cs irradiation facility for metrological application

Development of 137Cs irradiation facility for metrological application

Uncertainties Associated with Clonogenic Assays using a Cs-137 Irradiator and Ir-192 Afterloader: A Comprehensive Compilation for Radiation Researchers

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Product

Resources

About

Development of ¹³⁷Cs irradiation facility for metrological application

Development of ¹³⁷Cs irradiation facility for metrological application