Development of 99mTc labelled Lipiodol: biodistribution following injection into the hepatic artery of the healthy pig.

ABSTRACT

BACKGROUND: We develop a method for the radiolabelling of Lipiodol with Tc, using a lipophilic complex, [99mTc-(S2CPh)(S3Ph)2], dissolved in Lipiodol (99mTc-SSS Lipiodol). RESULTS: The labelling yield is high (96 +/- 0.8%), and the radiochemical purity satisfactory (92 +/- 2.6%). This labelling is reproducible and stable for up to 24 h in vitro. Studies carried out after injection into the hepatic artery of the healthy pig show that the biodistribution of 99mTc-SSS Lipiodol is comparable with that observed for 188Re Lipiodol. MATERIALS AND METHODS: The 99mTc-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with 99mTc, in cold lipiodol. The radiochemical purity (RCP) of the labelling was checked immediately and at 24 h. The 99mTc-SSS lipiodol was injected into the hepatic artery of four healthy pigs for an ex-vivo biodistribution study. An autoradiographic study was performed in two cases. CONCLUSIONS: Apart from the specific interest of a Lipiodol-bearing technetiated agent for carrying out dosimetric studies, the labelling of Lipiodol with 99mTc is a preliminary step towards the use of radiolabelling with the 188Re analogue.