Purpose: To evaluate the efficacy of single photon emission computed tomography (SPECT) images with N-isopropyl-p-[(123)I]-iodoamphetamine ([(123)I]-IMP) as a radiopharmaceutical for the diagnosis of uveal melanoma.
Methods: Consecutive interventional case series. Single photon emission computed tomography images were obtained after intravenous injection of [(123)I]-IMP in 20 patients with clinically suspected uveal melanoma (16 eyes of 16 patients) or ocular adnexal melanoma (four adnexal tumors of four patients). Histologic findings in seven eyes enucleated for uveal melanoma were analyzed with the SPECT images semiquantitatively evaluated.
Results: Eight of 20 eyes with suspected uveal melanoma showed high accumulation of [(123)I]-IMP in the late phase in the area corresponding to the uveal tumor, and the diagnosis of uveal melanoma was confirmed histologically in seven enucleated eyes. Tumor size and histologic features did not reflect the intensity of scintillation counts of [(123)I]-IMP. Twelve patients with no accumulation on the SPECT images were found to have clinically or histologically iris nevus, choroidal nevus, and other intraocular and adnexal conditions.
Conclusion: N-isopropyl p-[(123)I]-iodoamphetamine SPECT may serve as a sensitive and specific examination for the diagnosis of uveal melanoma.