Brain tumor imaging in rats using the positron emitting fatty aciddl-erythro-9,10-[18F]difluoropalmitate

Abstract

Positron emittingdl-erythro-9,10[¹⁸F]difluoropalmitate, [¹⁸F]DFPA, was synthesized for thein vivo imaging of brain tumors in rats. Male Fischer 344 rats were intracerebrally implanted with Walker 256 carcinosarcoma tumor cells (1×10⁶ in 5μ1 tissue culture media) and 7 days later were infused with [¹⁸F]DFPA (500-1000mCi/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 (Pn=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.