Positron emitting dl-erythro-9,10[18F]difluoropalmitate, [18F]
DFPA, was synthesized for the in vivo imaging of
brain tumors in rats. Male Fischer 344 rats were intracerebrally implanted with Walker 256
carcinosarcoma tumor cells (1 x 10(6) in 5 microliters tissue
culture media) and 7 days later were infused with [18F]
DFPA (500-1000 mCi/mmol) i.v. for 5 min. Rats were killed after 20 min. Brains were removed and either prepared for autoradiography, or brain and
tumor were separated and their radioactivity quantified by gamma spectroscopy.
Brain tumors were well demarcated from surrounding and normal brain in autoradiographs, and closely paralleled
tumor growth in histological sections. The mean optical density of
tumor was significantly greater, by 318 +/- 68 per cent (P less than 0.025, n = 3), than normal brain in autoradiographs, and that of edematous brain surrounding a large
tumor was intermediately increased. [18F]
DFPA proved of value to image and circumscribe intracerebral
tumors in awake rats, and studies are continuing to facilitate its clinical application in
brain tumor patients.