An Update on Extemporaneous Preparation of Radiopharmaceuticals Using Freeze-Dried Cold Kits

The field of nuclear medicine is rapidly evolving due to the high demand of radiopharmaceuticals for diagnostic and therapeutic applications. The availability of a vast array of radioisotopes, improvement in radiolabeling strategies, and advancements in detection systems have also contributed to the progress in this field. Radiopharmaceuticals are mainly classified based on their application as diagnostic or therapeutic radiopharmaceuticals. These are available either as ready to use preparations or prepared at hospital radiopharmacy either using automated synthesis modules or by using freezedried cold kit formulations. Availability of freeze-dried cold kits for preparation of varied radiopharmaceuticals for targeting various organs and tumors played an essential role in the extensive use of ^99mTc radiopharmaceuticals for diagnostic imaging by single-photon emission computed tomography (SPECT) imaging. Cold kits are especially suitable for the preparation of radiopharmaceuticals labeled with isotopes like ¹⁷⁷Lu with relatively long half-life or radionuclides produced by radioisotope generators. A simplified procedure for the preparation of positron emission tomography (PET) radiopharmaceuticals is also desired to achieve images with higher resolution and sensitivity offered by PET. Robust kit formulations will simplify the preparation of PET radiopharmaceuticals and will contribute to extensive applications of positron emitters such as ⁶⁸Ga. Several therapeutic radiopharmaceuticals are also being made using cold kits of the ligands. This review provides an update on diagnostic and therapeutic radiopharmaceuticals prepared using cold kits.