[Br-76]bromodeoxyuridine PET in tumor-bearing animals

5-bromodeoxyuridine (BUdR) provides in vitro measures of tumor cell prolife ration. We used positron emission tomography to study tissue and plasma kin etics of [Br-76]BUdR in tumor-bearing animals. In order to account for the slow washout of the major plasma metabolite, [Br-76]bromide, a mathematical correction for the distribution volume of [Br-76]bromide was applied. Howe ver, following correction specific tumor tracer retention was low or even z ero and did not correlate with independent measures of proliferation. The k inetic characteristics of [Br-76]BUdR make this tracer unsuitable for proli feration imaging. (C) 2001 Elsevier Science Inc. All rights reserved.