Technical report: automated classification of first and second cycle metaphases.

Based on the technical configuration of the Metafer2 metaphase finder (Metasystems, Altlussheim, Germany), an automated system was developed that is able to discriminate first/M1 or second cycle/M2 metaphases. For an evaluation of the system in fluorescence plus Giemsa stained preparations of human lymphocytes, a learning sample and an independent test sample was used. Between 8 and 14 separated chromosomes per metaphase were sufficient to achieve correct classification rates between 95 and 100%. For practical application the system can be most efficiently used for biodosimetry of human radiation exposure which requires scoring of thousands of metaphases exclusively in M1. An application for selection of M2 for SCE scoring in mutagenicity testing was possible, but does not provide a comparable advantage.