A cost-effective and flexible metaphase finder system for chromosomal biodosimetry

For biological dosimetry by counting chromosomes aberrations, automation technique has been required to process large number of sample preparations at low dose radiation exposure. Metaphase Finder is an automated optical microscope system, which automatically scans and finds metaphase cells on the slide glass, and relocates metaphase cells to the center of the field of view of the microscope to observe chromosomes in high magnification. These are several commercial products of metaphase finders, but these dedicated-system products are usually expensive and inconvenient for fitting to the variety of sample preparations. Now, we have constructed an improved system by assembling each components of the system, such as microscope, automated stage and computer, from the selection of the commercially available products, instead of purchasing one dedicated system. The new system has high cost-effectiveness and high flexibility in adapting to the new staining methods. This Metaphase Finder system consists of following components: an optical microsope, a motorized sample stage, an auto-focusing unit and two CCD cameras for focusing and for image acquisition. These components are controled by a personal computer. The image recognition software for detecting metaphase cells from the microscope image was developed on the programming environment provided by the general-purpose image analysis software. The processing speed of this Metaphase Finder system is 20 to 30 minutes per one slide glass (typical scan area is 20 mm x 50 mm), which is enough acceptable for practical use remarkably improved from the speed of our previous model of 1993. The algorithm for detecting metaphase cells has also improved to adapt to the variety of the condition of the sample preparation. This new system is scheduled to be distributed to several laboratories in Japan, and will be tested for the practical use.12th International Congress of Radiation Researc