A system for fluorescence metaphase finding and scoring of chromosomal translocations visualized by in situ hybridization.

Full automation on the scoring of radiation-induced chromosomal aberrations in conventionally stained metaphase spreads cannot be achieved reliably due to the complex image analysis problems involved. More success may be obtained by using in situ hybridization staining of the chromosomes. We describe the development of a system to detect metaphases on the basis of a fluorescent counterstain and subsequently analyze the number of translocations with the aid of whole chromosome paints fluorescing in a different colour. The system consists of a Macintosh IIfx computer, an automated Ergolux microscope equipped for fluorescence, and a Sony CCD camera. The performance of the metaphase finder was measured on a small set of slides counterstained with DAPI, whereas the suitability of the system for scoring aberrations was tested in a small feasibility study for the detection or radiation-induced translocations involving chromosome 4. The potentialities of the system for the use of multiple colours are discussed.