Technetium-99m-labeled lapachol as an imaging probe for breast tumor identification.

Objective: Breast cancer is a health problem worldwide with high incidence and mortality rates. It is well known that the development of more sensitive and specific diagnostic methods is of great importance since an early diagnosis is essential to successfully treat tumors. Lapachol is a natural compound, belonging to the naphthoquinone group that has been widely used in traditional medicine to treat various illnesses, including cancer. The aim of this study was to evaluate technetium-99m (Tc-99m) labeled lapachol as an imaging probe for breast cancer identification. Methods: To achieve this purpose, lapachol was labeled with Tc-99m, radiochemical purity and in vitro stability were determined. Blood clearance, in healthy mice, and biodistribution, in 4T1 tumor-bearing mice, were also evaluated. Results: Lapachol was successfully labeled with Tc-99m, with high values of radiochemical yield (95.9 +/- 3.4%). In vitro stability showed that the radiolabeled complex remained stable for up to 24 h, with values above 90% for both saline and plasma (95.6 +/- 3.6% and 96.4 +/- 1.7%, respectively). The radio labeled complex decays in a biphasic manner, with a half-life of distribution and elimination equal to 3.3 and 50.0 min, respectively. Biodistribution and scintigraphic images showed high uptake in organs of excretion (kidneys, liver, and intestine). It could be also noted that tumor uptake was higher than the muscle at all time points. Tumor-to-muscle ratio reaches similar to 4.5 at 24 h after administration. Conclusion: These findings suggest that Tc-99m-lapachol can be a potential diagnostic agent for breast tumors. (C) 2019 Sociedad Espanola de Medicina Nuclear e Imagen Molecular. Published by Elsevier Espana, S.L.U. All rights reserved.