Iodine-123-alpha-methyl tyrosine in gliomas: correlation with cellular density and proliferative activity.

Abstract

UNLABELLED: Amino acid transport rate in gliomas can be assessed using SPECT and the amino acid L-123I-alpha-methyl tyrosine (IMT). This study attempted to correlate the uptake of IMT by gliomas with the proliferative activity and cellular density of these neoplasms. METHODS: The study used 27 patients with gliomas, including 18 patients with high-grade tumors and nine patients with low-grade neoplasms. Amino acid transport rate was determined using IMT and the triple-headed SPECT camera. Proliferative activity was immunohistochemically assessed as the relative number of cells expressing the Ki-67 nuclear antigen; cellular density was evaluated using light microscopy. RESULTS: Relative IMT uptake correlated significantly with the proliferative fraction of tumor cells (r = 0.6, p < 0.001). There was no significant correlation between IMT uptake and cellular density (r = 0.25, p > 0.05). CONCLUSION: The uptake of the SPECT radiopharmaceutical IMT is related to proliferative activity rather than to the cellular density of gliomas.