Evaluation of a metaphase chromosome finder: potential application to chromosome-based radiation dosimetry

An automated metaphase chromosome finder is described which combines a microscope, state-of-the-art computer technology and a simple decision-making algorithm. A microscope slide is systematically scanned under computer control and the location of each positive 'signal' placed into memory for later recall and review by a human operator. The software identifies two events, positives (the presence of a 'signal') and negatives (the absence of a 'signal'). The performance of the metaphase finder was evaluated using receiver operating characteristic curve analysis. At the optimum decision threshold, the detection rates for true positives (metaphase spreads) was about 74%, false positives (type I error) about 6%, and false negatives (type II error) about 26%. The overall accuracy, which accounts for differences in the sensitivity of the detector to positive and negative events, was 89.4% (+/- 0.01%; standard error of the mean, n = 8). Potential applications to radiation dosimetry are discussed.