TOXICITY AND RADIATION-DOSE OF 2-[F-18]-2 -DEOXY-D-GLUCOSE DURING POSITRON-EMISSION-TOMOGRAPHY

2-[F-18]-FDG, a non-physiological glucose analogue, is the most import ant positron-emission-tomography (PET) radiopharmaceutical. As an exam ple we refer to the production of 2-[F-18]-FDG at the research center in Karlsruhe. 2-[F-18]-FDG is synthesized in a ''no carrier added'' pr ocess. It is delivered at a maximal filling volume of 10 ml from a 14. 5 ml batch with a batch-to-batch yield fluctuation from 5075 to 50,750 MBq and a specific activity from 1 to 10 GBq/mu mol. The residual rem aining synthesis reagents like solvents or catalysts have no toxicolog ical relevance. The applicated dose per patient is in a range from 185 to 370 MBq and 1000 times lower than the correlating concentrations o f stable FDG which can be regarded harmless in animals. 2-[F-18]-FDG d oes not interfere with normal glucose metabolism. It is taken up by ce lls and phosphorylated to 2-[F-18]-FDG-6-phosphate. The following deph osphorylation step is slow and the labeled compound is retained over s everal hours within the cells. Non-metabolized 2-[F-18]-FDG is excrete d rapidly in the urine to an extent of about 16% after 60 min, and 50% after 135 min, respectively. Fluorine-F-18 decays by emission of 511 KeV gamma photons. The whole body effective dose is reported to be 21 to 27 mu Sv/MBq. In case of an intravenous injection of 370 MBq this l eads to a total dose of 7.8 to 10 mSv. The critical organ is the bladd er wall (radiation dose 120 to 170 mu Sv/MBq or 80 to 100 mrem/mCi). T he risk of a radiation induced late malignoma at 10 mSv can be estimat ed to be 1 : 2000; The genetical risk as a consequence of FDG-PET diag nostics would be 1 : 100,000 to 2 : 100,000 for dominant, and 5 times higher for recessive mutations.