[en] Full text: ¹⁵³Sm-EDTMP injection is the preferred radiopharmaceutical for the palliative treatment of bone pain due to the excellent clinical efficacy and minimal myelosuppression in comparison to other bone pain palliative radiopharmaceuticals. However owing to short half life of ¹⁵³Sm (46 h), shelf life of ¹⁵³Sm-EDTMP injection is limited. This in turn poses a number of logistic and operational problems namely, availability of radioisotope, radiochemical processing time, quality control testing, packing and transportation and administration to patients within a limited time. BRIT has been manufacturing and supplying this radiopharmaceutical since 1999, however during the last 2-3 years there has been a gradual increase in demand. Presently the amount of radioactivity, of ¹⁵³Sm, has gone up from 1-2 Ci per batch to 4-5 Ci per and it is increasing. Considering increased radioactivity per batch, for the preparation of ¹⁵³Sm-EDTMP injection, and production procedure with steam sterilization step, there is increased possibility of radiation exposure, thus serious concern for radiation safety from personnel and environmental point of view. In order to reduce this probability in accordance with ALARA principle, the whole production process has been modified. A new modular production protocol has been developed and adopted, suitable for easy operation in the existing production plant, for handling large batches without compromising on the quality parameters of the final product. This paper gives the details of the modified production process, involving the three operation modules. First module comprises of heating the reaction mixture containing ligand EDTMP and the calculated quantities of ¹⁵³Sm radioactivity. Second module is for on-line sterilization of the product by membrane filtration (0.22μ). Third module is for aseptic dispensing of unidose activity, in multiple pre-sterilized vials and sealing with sterilized combination seals. Using these semi automated techniques and gadgets and production modules, several therapeutic batches of ¹⁵³Sm-EDTMP injection have been processed, QC tested (radiochemical purity, radionuclidic purity, sterility test, bacteriological endotoxin test) and more than 100 doses (70 mCi each) have been supplied for clinical use, to various Nuclear Medicine Centers in India. Regular production of this product (BRIT Code SAM-2) is being undertaken on monthly frequency