SCORING OF RADIATION-INDUCED MICRONUCLEI IN CYTOKINESIS-BLOCKED HUMAN-LYMPHOCYTES BY AUTOMATED IMAGE-ANALYSIS

The micronucleus assay in human lymphocytes is, at present, frequently used to assess chromosomal damage caused by ionizing radiation or mut agens. Manual scoring of micronuclei (MN) by trained personnel is very time-consuming, thing work, and the results depend on subjective inte rpretation of scoring criteria. More objective scoring can be accompli shed only if the test can be automated. Furthermore, an automated syst em allows scoring of large numbers of cells, thereby increasing the st atistical significance of the results. This is of special importance f or screening programs for low doses of chromosome-damaging agents. In this paper, the first results of our effort to automate the micronucle us assay with an image-analysis system are represented. The method we used is described in detail, and the results are compared to those of other groups. Our system is able to detect 88% of the binucleated lymp hocytes on the slides. The procedure consists of a fully automated loc alization of binucleated cells and counting of the MN within these cel ls, followed by a simple and fast manual operation in which the false positives are removed. Preliminary measurements for blood samples irra diated with a dose of 1 Gy X-rays indicate that the automated system c an find 89% +/- 12% of the micronuclei within the binucleated cells co mpared to a manual screening. (C) 1994 Wiley-Liss, Inc.