Challenges of analysing suspected over exposed subjects using biological dosimetry at Sri Ramachandra University

Biological dosimetry based on the analysis of dicentric chromosomes has become a routine component of the radiological protection programmes and has a valuable role to contribute in suspected over exposed subjects who perform diagnostic and therapeutic procedures. The Department of Human Genetics, Sri Ramachandra University, Porur, Chennai, has been involved in the standardization of chromosomal aberration analysis as a biological dosimeter for investigating accidental ionising radiation exposure since 1998. Our laboratory has been accredited since 2007 by Atomic Energy Regulatory Board. The initial process was to establish the in vitro dose response curve for various type of low LET ionizing radiation. Since accreditation, a total of 61 subjects have been referred to Sri Ramachandra University from SRRC, Kalpakkam. Brief social/medical history and informed consent are being obtained prior to blood samplings. The dose estimates expressed in sievert (Sv) measured by Thermoluminescence badges was in the range of 0.05-2779.05 mSv. Chromosomal aberration assay was used for analysis which allows direct detection of aberration in peripheral blood lymphocytes. The test was performed as per the standard operating protocol on peripheral blood lymphocyte. Currently the dose response curve for the automated scoring process in under way and we hope to improve upon quality and turnaround time using the automation available. Future challenge would be to establish an in vitro dose response curve with automated scoring technique and developing inter-laboratory comparison of dose response generated using automation