A dosimetric analysis was performed to evaluate nanoliposomes as carriers of radionuclides (188Re-liposomes) and radiochemotherapeutic drugs [188Re-doxorubicin (DXR)-liposomes] in internal radiotherapy for colon carcinoma, as evaluated in mice. Methods: Pharmacokinetic data for 188Re-N, N-bis (2-mercaptoethyl)-N′,N′-diethylethylenediamine (BMEDA), 188Re-liposome, and 188Re-DXR-liposome were obtained for the estimation of absorbed doses in tumors and normal organs. Two colon carcinoma mouse models were employed: subcutaneous growing solid tumor and malignant ascites pervading tumor models. Radiation-dose estimates for normal tissues and tumors were calculated by using the OLINDA/EXM program. An evaluation of a recommended maximum administered activity (MAA) for the nanotargeted drugs was also made. Results: Mean absorbed doses derived from 188Re-liposome and 188Re-DXR-liposome in normal tissues were generally similar to those from 188Re-BMEDA in intraperitoneal and intravenous administration. Tissue-absorbed dose in the liver was 0.24–0.40 and 0.17–0.26 (mGy/MBq) and in red marrow was 0.033–0.050 and 0.038–0.046 (mGy/MBq), respectively, for 188Re-liposome and 188Re-DXR-liposome. Tumor-absorbed doses for the nanotargeted 188Re-liposome and 188Re-DXR-liposome were higher than those of 188Re-BMEDA for both routes of administration (4–26-fold). Dose to red marrow defined the recommended MAA. Conclusions: Our results suggest that radionuclide and chemoradiotherapeutic passive targeting delivery, using nanoliposomes as the carrier, is feasible and promising in systemic-targeted radionuclide therapy.
