p-[18F]Fluorobenzylguanidine ([
18F]PFBG) is a
norepinephrine analog that has been developed as a positron emission tomography (PET) imaging
radiopharmaceutical. Myocardial sympathetic innervation, neuroendocrine structures, and
tumors can be noninvasively imaged with [
18F]PFBG. In this study, the uptake characteristics of [
18F]PFBG were investigated in 2 dogs with a spontaneous
pheochromocytoma. The extent of the
pheochromocytoma was well documented in both dogs on the PET study. The standardized uptake values within the
pheochromocytomas were greater than 25 by 10 min, and were 37 and 50 by 45 min in each dog. A third dog that was suspected to have an adrenal mass was also studied. In this dog, the [
18F]PFBG study was normal. Surgical exploration and adrenal biopsy confirmed the [15F]PFBG imaging findings in both dogs. In each dog, there was rapid blood-pool clearance (within 10 min after
intravenous administration of the [
18F]PFBG), with high uptake specific within the myocardium and adrenal medulla. The results indicate that [
18F]PFBG may be useful for imaging canine
pheochromocytomas and aid in differentiating adrenal masses.