A technetium-99m-labelled cyclam acid porphyrin (CAP) for tumour imaging

Abstract

A new water-soluble cyclam acid porphyrin (CAP), 5,10,15,20-tetrakis- [4-{4',8',11'-tris(carboxymethyl)-1'-(1',4',8',11'-tetraazacyclotetradecane)amidomethyleneoxy} phenyl] porphyrin has been synthesised, characterised and labelled with Tc-99m. In vivo distribution studies were performed in C-6-gliomas and N-nitroso-N-methylurea (NMU) induced mammary tumour bearing rats and scintiimages were obtained at 5 h post-administration of the labelled ligand using gamma camera computer system. Tumour to muscle (T/M) ratios were determined and compared with currently available tumour seeking radiopharmaceuticals such as Tc-99m(V)-DMSA, Tc-99m-Citrate and (TlCl)-Tl-201. In the case of NMU induced mammary tumour rats the ratios were 6.93, 1.97, 5.30 and 3.29; while in the case of C-6-gliomas the ratios were 5.58, 2.18, 3.96 and 3.02 for (99m)-Tc-CAP, (99)mTc(V)-DMSA, Tc-99m-Citrate and (TlCl)-Tl-201, respectively. (C) 2001 . .