PET imaging drug distribution after intratumoral injection: the case for (124)I-iododeoxyuridine in malignant gliomas.

Abstract

Although a single injection of (124)I-IUdR resulted in radioactivity distribution over the tumor, retention at 24 h was substantially lower compared with intravenous injection of (124)I-IUdR. Slow diffusion after locoregional administration, in contrast to fast delivery via tumor capillaries after intravenous injection, may account for our findings, resulting in a low amount of drug incorporation into DNA before degradation and washout from tissue.