Biological response of digestive system in experimental study of 177Lu-based compound

Purpose. To compare information about the condition of the digestive tract obtained by ex vivo radiometry and in vivo imaging methods after administration of 177 Lu-DOTA-TATE to rats. Materials and methods. The compound 177 Lu-DOTA-TATE was synthesized in the cyclotron-radiochemical laboratory of the Department of Radionuclide Diagnostics and Therapy of the N. N. Blokhin National Medical Research Center of Oncology. SPECT/CT method was used to visualize the digestive tract of laboratory rats after administration of 177 Lu-DOTA-TATE. Classical direct radiometry of post mortem biological samples was used as a comparison method. In vivo imaging was performed sequentially in dynamic mode with MilLabs VECTOR6 small animal imaging system. In direct radiometry, signal from the radioisotope was detected with "WIZARD 2480" system. Safety of the compound 177 Lu-DOTA-TATE was assessed with standard toxicological methods. Results. The safety of the compound was assessed. Biodistribution data was obtained with ex vivo and in vivo methods, the results were compared. Conclusion. In the preclinical toxicological study, 177 Lu-based compound was recommended for further investigation. Pancreas uptake of the radioactive compound was consistent with literature data. For the small and large intestine, differences in feasibility of uptake detection with ex vivo and in vivo methods were shown. This fact should be taken into account when planning similar experiments for gastrointestinal cancer.