The quality of 99mTc-radiopharmaceuticals –a basic requirement in the diagnostic
- Ivanova, H. Popsavova, I. Kostadinova
Abstract. The development and application of new high quality radiopharmaceuticals (RP) are of a great significance for the development in nuclear medicine. The high quality of the radiopharmaceuticals has a major influence on the accuracy of nuclear medical examinations. Therefore, a good knowledge and application of various control methods, is essential. Radiochemical impurities affect the quality of RP most significantly and they can appear at every stage of the preparation. The aim of this review is to present the literature information concerning the quality of the most commonly used radiopharmaceuticals, labeled with 99mTc, and all requirements for them, i.e. radiochemical, radionuclide, and chemical purity. This is well-known fact that metastable isotope of Technetium is golden standard for diagnostics in nuclear medicine. Research shows that about 80% of approximately 25 million nuclear medical studies a year are performed with this radionuclide. According to the European Pharmacopoeia and to the leaflets provided with the kits, radiochemical purity must exceed 95%. The main radiochemical impurities in 99mTcradiopharmaceuticals are free pertechnetate (99mTcO4-), whose presence causes accumulation of RP in the thyroid gland, stomach, gastrointestinal tract, or the salivary glands, leading to a wrong diagnosis, and reduced hydrolyzed technetium, which causes visualization of the reticulo-endothelial system. This paper contains information about the authors’ experience with analyses of the radiochemical purity of the two most commonly used radiopharmaceuticals in Bulgaria – for bone and renal scintigraphy (MDP and DTPA). An ITLC (Instant Thin-Layer Chromatography) is used for this purpose. It is concluded that the high quality of the applied 99mTcradiopharmaceuticals can be guaranteed only with both selection of renowned manufactures, recognized by EU, and a routine daily control of the labeling and generator eluate, meeting all requirements of the manufacturer and observing all regulations for work in nuclear medical centers in the country.
Key words: 99m TC-RADIOPHARMACEUTICALS. QUALITY
CONTROL. THIN LAYER CHROMATOGRAPHY