In 1966 he moved into cancer-related research, specifically at National Institutes of Health and later the National Cancer Institute where he turned his interest in visual pattern recognition to medical imaging applications.[1][9] He also worked on efficient algorithms for screening chemical compounds for studying chemical carcinogenesis.[1][10][11][12][13][14] His work on models of clustering for chemical compounds was pronounced a "milestone" by the Developmental Therapeutics Program of the National Cancer Institute, for "revolutioniz[ing] the selection of compounds of interest by measuring the novelty of a chemical structure by comparing it to known compounds."[15]