Semi-automated micronucleus scoring in cytokinesis-blocked lymphocytes after irradiation.

A semi-automated scoring procedure for the cytokinesis-block micronucleus assay based on computerized image analysis was validated by comparing results of the automated analysis with those from manual analysis by those experienced scorers of micronuclei. Each object selected by the computer system was also relocated and visually inspected. The validation was based on slides of blood samples after in vitro irradiation with X-rays in the low-dose range up to 2 Gy. Up to 1 Gy a very satisfactory agreement between manual and semi-automated scoring was obtained. At 2 Gy the micronucleus yields obtained by the semi-automated scoring were systematically below the manual data due to a small percentage of false negatives (3%). Using the appropriate dose-response relationship the validation study indicates that the results obtained by computerized image analysis are comparable to manual scoring with respect to accuracy. The computerized assay is superior regarding reproducibility. At present, semi-automated scoring of micronuclei is practically feasible for a limited number of slides for large-scale applications of the semi-automated micronucleus is assay in the field of radiation protection an increase of the speed of the system is necessary.