Glucose analogs as potential diagnostic tracers for brain tumors.

No tumor-specific tracer has yet been found for the detection of brain tumors by external scintiscanning. Glucose is a substrate in high demand by almost all tumors, and therefore an investigation was undertaken into the potential value of glucose and its analogs as tracers for brain tumors. The compounds studied were D-)1-3H)glucose, D-(1-14C)glucose, (3H)3-O-methyl-D-glucose and L-(1-14C)glucose. The tracers were injected i.v. into C57BL/6J mice carrying a transplantable s.c. ependymoblastoma. At specific time intervlas after injection, mice were sacrificed and the radioactivity of 6 tissues including tumor and brain were assayed by means of an automated combustion technique and liquid scintillation counting. Tumor uptake, expressed as percentage mean body concentration, was 60% for 2 of the tracers, and 92 and 143%, respectively, for 2 others. Brain uptake was over 130% mean body concentration, with 3 of the 4 tracers studies. With L-glucose, brain uptake was only 15.4% mean body concentration, and a maximum tumor-to-brain ratio of 9.5 was achieved. The very high tumor uptake achieved with two of these carbohydrated demonstrates that a carbohydrate analog may be found that shows high tumor specificity and uptake, and that may be useful for external scintiscanning.