Application of Premature Chromosome Condensation and Dicentric Analysis in Retrospective Biological Dosimetry of Radiation Accident

Cytogenetic dosimetry based on dicentric analysis and premature chromosome condensation plays an important role in the triage and medical management of affected people in radiological accidents. In our studies, blood samples from persons that were suspected of accidental exposure to ionizing radiation during interventional radiology procedure (plastic surgery of the renal arteries) were investigated for the purpose of the retrospective biological dosimetry of absorbed dose. In this case, the obligatory reported dose value, kerma area product, was high: 106.04 Gy cm(2). The peak skin dose was reported by X-ray machine system as 17 Gy. Peak skin dose for an iso-centric interventional fluoroscope is measured at defined reference point, located 15 cm from the isocenter toward the X-ray tube. Due to the lack of possibility to connect kerma area product with an effect (kerma area product could be connected with the maximum local dose in the X-ray field) the patient's blood and 2 most-at-risk people (medical doctors) were investigated. In addition, 5 dosimeters for the whole body (Hp(10)) and 1 ring dosimeter measuring the skin exposure (Hp(0.07)) of medical workers participating in the radiological procedure were investigated. The measurements of individual doses by the thermoluminescent dosimeters were carried out by the Laboratory of Individual and Environmental Dosimetry (Polish acronym LADIS). To estimate the potentially absorbed dose lymphocytes from blood were analyzed for the presence of chromosomal aberrations (dicentrics and rings), which are the "gold standard" assay for biodosimetry. Additionally, the absorbed dose was monitored by the analysis of excess fragments with premature chromosome condensation technique, which is recommended for high doses and partial body exposure. Finally, estimated doses for obtained blood samples were compared to the dose-response curves for dicentrics and premature chromosome condensation excess fragments, detected in our laboratory after induction in human lymphocytes by in vitro X-ray irradiation.