Investigation of the influence of calibration practices on cytogenetic laboratory performance for dose estimation

Abstract

Purpose: In the frame of the QA program of RENEB, an inter-laboratory comparison (ILC) of calibration sources used in biological dosimetry was achieved to investigate the influence of calibration practices and protocols on the results of the dose estimation performance as a first step to harmonization and standardization of dosimetry and irradiation practices in the European biological dosimetry network. Materials and methods: Delivered doses by irradiation facilities used by RENEB partners were determined with EPR/alanine dosimetry system. Dosimeters were irradiated in the same conditions as blood samples. A short survey was also performed to collect the information needed for the data analysis and evaluate the diversity of practices. Results: For most of partners the deviation of delivered dose from the targeted dose remains below 10%. Deviations larger than 10% were observed for five facilities out of 21. Origins of the largest discrepancies were identified. Correction actions were evaluated as satisfactory. The re-evaluation of some ILC results for the fluorescence in situ hybridization (FISH) and premature chromosome condensation (PCC) assays has been performed leading to an improvement of the overall performances. Conclusions: This work has shown the importance of dosimetry in radiobiology studies and the needs of harmonization, standardization in irradiation and dosimetry practices and educational training for biologists using ionizing radiation. ARTICLE HISTORY

A general mechanistic model enables predictions of the biological effectiveness of different qualities of radiation

“…These experimental uncertainties include differences in cell handling which are not typically reported in detail (e.g. cell cycle differences resulting from different times from plating to irradiation 29 ), systematic and random experimental uncertainties (a recent report indicated laboratory radiation sources often have calibration errors of 10% or more 30 ) and differences in irradiation protocol which are not currently implemented including dose rate and any RBE effects seen with low energy X-rays 31 ).…”

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA)

“…Inherent variability on delivered dose from one radiation facility to another can be responsible for systematic bias. More details about this issue are discussed by Trompier et al (2016) in this special issue.…”

The harmonization process to set up and maintain an operational biological and physical retrospective dosimetry network: QA QM applied to the RENEB network

“…However, when based on the dose, the calibration of the radiation facility has to be similar between the different laboratories estimating the dose, i.e. same units (Trompier et al 2016b). If not, some discrepancies between biological dose assessments can be attributed to differences in protocols, in calibration curves rather than in calibration of radiation facilities.…”

“…The QA&QM manual defines rules regarding: (1) role of the responder reference laboratory and the service laboratory; (2) information on the radiation sources used for doseeffect curves or for irradiation of samples for inter-comparison (Trompier et al 2016b); (3) information on the establishment of calibration curves for the different assays; (4) performance of sample collection and sample preparation by assay; (5) conversion of the specific observed criteria of the assay into an estimate of absorbed dose; (6) report of minimum dose detection level, results and quality controls; (7) organization of inter-comparisons; (8) quality assurance and quality management of RENEB laboratories.…”