Electron- and Positron-Emitting Radiolanthanides for Therapy: Aspects of Dosimetry and Production

All lanthanides have similar chemical properties regarding label-ing. Therefore, radiolanthanides that have been used for therapy, such as 153Sm and 177Lu, might easily be replaced with other radiolanthanides. The aim of this workwas to investigate the suit-ability of electron- and positron-emitting radiolanthanides for ra-dionuclide therapy with reference to dosimetry and production possibilities. Methods: Radiolanthanides with half-lives of 1 h to 15 d, stable or long-lived daughters, and limited photon emis-sion were selected. The ratio of the absorbed dose rate to the tumors and the normal tissue (TND ̇ ) was calculated for different tumor sizes and compared with the TND ̇ values for 90Y and 131I. The normal tissue and tumors were simulated as an ellipsoid and spheres, respectively. The TND ̇ values depend on the physical parameters of the radionuclides, the tumor size, and the ratio be-tween the activity concentrations in the tumor and normal tissu