Novel MR imaging contrast agents for cancer detection

Background: novel potential mr imaging contrast agents gd-tetra-carboranylmethoxyphenyl-porphyrin (gd-tcp), gd-hematoporphyrin (gd-h), gd-dtpa-9.2.27 against melanoma, gd-dtpa-wm53 against leukemia and gd-dtpac595 against breast cancer cells were synthesized and applied to mice with different human cancer cells (melanoma mm-138, leukemia hl-60, breast mcf-7). the relaxivity, the biodistribution, t1 relaxation times, and signal enhancementof the contrast agents are presented and the results are compared.jviethods: after preparation of contrast agents, the animal studies were performed. the cells (2x 106 cells) were injectedsubcutaneously in the both flanks of mice. two to three weeks after tumor implantation, when the tumor diameterwas 2-4 mm, mice were injected with the different contrast agents. the animals were sacrificed at 24 hr post ip injectionfollowed by removal of critical organs. the t1 relaxation times and signal intensities of samples were measured using 11.4 t magnetic field and gd concentration were measured using uv-spectrophotometer.results: for gd-h, the percent ofgd localized to the tumors measured by uv-spect was 28, 23 and 21 in leukemia, melanoma and breast cells, respectively. for gd-tcp this amount was 21%, 18% and 15%, respectively. for gd-dtpa-9.2.27, gd-dtpa-wm53 and gd-dtpa-c595 approximately 35%,32% and 27% of gadolinium localizedto their specific tumor, respectively.conclusion: the specific studied conjugates showed good tumor uptake in the relevant cell lines and low levels of gdin the liver, kidney and spleen. the studied agents have considerable promise for further diagnosis applications of mr imaging.