Clinical Radiopharmacy

QUALITY CONTROL IN NUCLEAR MEDICINE

        Due to their use as agents for diagnostic radiology, radiopharmaceuticals should be subject to certain quality control procedures to ensure their quality. Although radiopharmaceuticals providers, both local and business firms, conducted a thorough quality control on their products, many of radiopharmaceuticals are prepared in the Department of Nuclear Medicine from reagent kits and short lived radioisotopes ( 99m).

        From the viewpoint of radiation safety and image quality, if it is poor means that the study should be repeated increasing the cost and time to the department, in addition to discomfort and increased radiation dose to the patient. This can and should be avoided spending a short period of time each morning for the corresponding quality control.

Technetium-99m Radiopharmaceuticals

        Once the generator eluate controls the next step is to determine the percentage of hydrolyzed low Tecnetium-99m (colloid) in the eluate, and determining the radiochemical purity of the freshly prepared 99mTc radiopharmaceuticals.

        There are two radiochemical impurities which may appear in any compound of Tc99m: Tecnetium-99m free (as pertechnetate TcO4 99m) and 99m Tc-colloid (probably as TcO (OH) 2 x H2O Tecnetium-99m a hydrated oxide). In all soluble Tc99m radiochemicals it is necessary to discard the presence of both impurities.

        During the labeling process, some of the latest generation of radiopharmaceuticals and radiotracers are produced in a chemical form clinically useful, but may change after a short period of time and converted into another chemical form not having good clinical value as the first one. It is extremely important to identify and quantify the presence of these impurities before administration into the patient, to avoid  test repetition.

        As indicated by the technical specifications, in the latest generation of radiochemicals such as HMPAO, MAG3, MIBI, ECD, etc., it is mandatory to do quality control procedures to rule out poor labeling or other byproducts. For other compounds of Tc-99m this procedure is optional but highly recommended.

References:

1   The Chemistry of Technetium in Medicine. Joseph Steigman and William C. Eckelman, 1992

2   Nuclear Imaging in Drug Discovery, Development and Approval. Eds. H. Donald Burns, Raymond E. Gibson, Robert F. Dannals, Peter K. S. Siegl. Birkhauser Boston, 1993.

3   William C. Eckelman and Richard C. Reba. The Classification of Radiotracers. J.Nucl.Med. 19 Nº 10: 1170-1181, 1978.

4   Suresh C. Srivastava, In: Current Directions in Radiopharmaceuticals. Ed. S.J. Mather, 1996

5   Gil MC, Araya G y Tomicic M.  Fundamentos de Radiofarmacia pp: 11-18. Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González.  Editorial Masson, Barcelona España, 2003.

6   Fundamentos de Radiofarmacia. C.O. Cañellas.Tecnonuclear. Formato CD. 2007.

Page 4    Home       Index      Clinical Nuclear Medicine       Therapeutic Methods   Previous Page