en Absorption, Distribution, Metabolism and Excretion پژوهشي Research Article <div style="text-align: justify;">The purpose of the present work was to introduce ¹⁴¹Ce-EDTMP as a novel potential future pain palliative agent to patients suffering from disseminated skeletal metastases and diagnostic imaging radioisotope as well<em>.</em> Cerium-141 [T_1/2 = 32.501 days, E_&beta; (max) = 0.580 (29.8%) and 0.435(70.2%) MeV, E_&gamma; = 145.44 (48.2%) keV] possesses radionuclidic properties suitable for use in palliative therapy of bone metastases. ¹⁴¹Ce also has gamma energy of 145.44 keV, which resembles that of ^99mTc. Therefore, the energy window is adjustable on the Tc-99m energy because of imaging studies. ¹⁴¹Ce can be produced through a relatively easy route that involves thermal neutron bombardment on natural CeO₂ in medium flux research reactors (4&ndash;5&times;10¹³ neutrons/cm²&middot;s). The requirement for an enriched target does not arise. Ethylenediamine (tetramethylene phosphonic acid) (EDTMP) was synthesized and radiolabeled with ¹⁴¹Ce. The experimental parameters were optimized to achieve maximum yields (>99%). The radiochemical purity of ¹⁴¹Ce-EDTMP was evaluated by radio-thin layer chromatography. The stability of the prepared formulation was monitored for one week at room temperature, and results showed that the preparation was stable during this period (>99%). Biodistribution studies of the complexes carried out in wild-type rats exhibited significant bone uptake with rapid clearance from blood. The images showed high uptake of complex in bone after 72h and 2 weeks clearly. The percentage injected dose per gram of tissue (%ID/g) for each organ or tissue was calculated. The results show significant bone uptake with rapid clearance from blood. The properties of produced ¹⁴¹Ce-EDTMP suggest applying a new efficient bone pain palliative therapeutic agent to overcome metastatic bone pains.</div> &nbsp;<br> &nbsp; Cerium-141, Bone pain palliative, EDTMP, Radiopharmaceutical, Biodistribution 1 7 http://ijpt.iums.ac.ir/browse.php?a_code=A-10-38-2&slc_lang=en&sid=1 FATEMEH SOLTANI 10031947532846001597 10031947532846001597 No Department of Medical Radiation Engineering, Science & Research Branch, Islamic Azad University, Tehran, Iran SIMINDOKHT SHIRVANI ARANI 10031947532846001598 10031947532846001598 No Radiopharmaceutical Research and Development Lab (RRDL), Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran MAHDI SADEGHI sadeghi.m@iums.ac.ir 10031947532846001596 10031947532846001596 Yes Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran SAMIRA HEIDARI 10031947532846001599 10031947532846001599 No Medical Physics Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran ALI BAHRAMI SAMANI 10031947532846001600 10031947532846001600 No Radiopharmaceutical Research and Development Lab (RRDL), Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran KAMAL YAVARI 10031947532846001601 10031947532846001601 No Radiopharmaceutical Research and Development Lab (RRDL), Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran