synthesis and application of new gadolinium-porphyrins as potential mr imaging contrast agents for cancer detection in nude mice

two new potential magnetic resonance imaging contrast agents, gd-hematoporphyrin (gd-h) and gd-tetra-carboranylmethoxyphenyl-porphyrin (gd tcp), were synthesized and applied to nude mice with human melanoma (mm 138) xenografts. these agents showed a high relaxivity because of their greater potential to coordinate water molecules. the reduction of t1 relaxation times of 16 and 21% was observed in human melanoma tumors grafted in the nude mice 24 h after injection of gd-tcp and gd-h, respectively. the percent of injected gd, that localized to the tumor and measured by inductively coupled plasma atomic emission spectroscopy (icp-aes), was approximately 21% for gd-tcp and 28% for gd-h. a higher concentration of gd was achieved compared with control indicating selective delivery of gd-porphyrins to the melanoma xenografts. the data indicate that gd-tcp can be used as a dual probe for diagnosis in mr imaging and for therapy in boron neutron capture therapy (bnct).