Transaxial PET images investigate p53 gene expression in rats implanted with a test tumor in the left shoulder, a negative control tumor in the right shoulder, and a positive control xenograft in the thigh (not shown). The animal treated with BCNU chemotherapy (right) exhibits localized radioactivity in the test tumor but no radioactivity above background in the negative control. Nontreated animal shows no localization radioactivity in either the test or negative control xenografts.
(Provided by R. Blasberg)

National Cancer Institute chief Dr. Richard D. Klausner has pumped considerable funds into molecular imaging research.