[en] 6-[¹⁸F]Fluoro-l-dopa (6FD) has been proposed and used for probing cerebral dopamine metabolism by positron emission tomography. Recently a new method for asymmetric synthesis of 6FD has been reported. This method involves synthesis of 6-[¹⁸F]fluoro-3,4-dimethoxybenzylbromide which is reacted with (S)-1-Boc-2-tert-butyl-3-methyl-4-imidazolidinone. The resulting alkylated compound is then hydrolyzed with hydriodic acid to produce 6FD. This method has been used to produce 6FD and several critical steps that required attention found, in addition to some modification for successful 6FD production. 6FD is prepared in 6-13% radiochemical yield (decay not corrected) after HPLC purification with a production time of 85 min

[en] Gamma activities of 36 brick samples around Tehran (Iran) have been determined using gamma spectrometry. The average values of the measured activities are 34±5, 32±4 and 615 ± 63 Bq Kg^-1 for ²²⁶ Ra, ²³² Th and ⁴⁰ K respectively. The estimated radium equivalent concentration is 127 ± 14 Bq Kg^-1 . This value is comparable with the reported values for many countries in the world. The internal and external hazard indices vary from 0.25 to 0.36 and 0.28 to 0.4 respectively. Therefore, these bricks are not a major sources of radiation hazards

[en] Data presented on pharmacological effects of gadolinium labeled disofenin (DISIDA) upon administration of large mass amounts suitable to produce MR contrast prompted us to investigate these effects with technetium labeled DISIDA. A variable mass of [sup(99m)Tc]Tc-DISIDA, 0.05-100 mg, was administered to rabbits. The effective half life in the liver did not vary significantly for doses between 0.05 and 5 mg, with an average of about 17 min. However, the effective half life increased to about 300 min for a 100 mg dose of DISIDA. (author)

[en] I-123 labeled N-isopropyl-p-iodoamphetamine (IMP) has been shown to be an important and useful radiopharmaceutical for measurement of cerebral blood flow. Since substituted amphetamines have a strong pharmacological activity, the synthesis of ''No Carrier Added'' (NCA) labeled IMP would be desirable. In this paper we report a modified and improved method for the synthesis of para-halogenated-N-isopropylamphetamine and the preparation of NCA I-131 IMP. This procedure involves a labeling reaction using I-131 sodium iodide and para-bromo-N-isopropyl amphetamine (BrMP) followed by HPLC separation of I-131 IMP and BrMP using reverse phase chromatography. (author)

[en] The purpose of the study was to develop an MR imaging contrast agent that would specifically localize in the liver and subsequently be excreted into the biliary tree. Gadolinium-DTPA dihexadecylamide was injected into rabbits. In each case, ''carrier-added'' Gd-153 with specific activity of 1.0 μCi/mg was used. Before injection, each rabbit was imaged in a 0.6-T clinical imager to serve as its own control. Postinjection gamma camera scintigraphy and postinjection MR imaging were then performed. Scintiphotos made 5 minutes after injection showed excellent uptake in the liver. At 1 hour after injection there was definite activity in bowel, indicating excretion of the agent into the bile. Comparison of preinjection and postinjection T1 values for the liver showed 60% shortening of T1 relaxation time. Biodistribution studies revealed that most of the activity accumulated in the liver in the first few minutes. Gd-DTPA dihexadecylamide shows great promise for hepatobiliary MR imaging

[en] Short communication

[en] Technetium-99m MDP was prepared from MDP kits from several different sources. The resulting [/sup 99m/Tc]MDP preparations were analyzed by electrophoresis. The results demonstrated the presence of at least four different /sup 99m/Tc complexes in these preparations. Modified kit preparations were analyzed to show the effects of concentration and pH on formation of the impurities. The electrophoresis results were correlated with scintillation camera imaging studies in rabbits and suggest that hydrolysis of MDP to phosphate and methylphosphate results in formation of /sup 99m/Tc complexes with poor biological behavior as bone scanning agents

[en] Short communication

[en] Short communication

[en] The use of DTPA bicyclic anhydride of DTPA and N-hydroxy succinimide pentaester of DTPA to attach DTPA to different proteins have been reported. However, there is indication in the literature that alternative methods are needed. We have now synthesized N-hydroxy succinimide diester of DTPA for this purpose. The synthetic procedure is quite simple and this molecule has been shown to be stable. The maximum coupling efficiency occurs at pH=7.0, reaction time is about 10 min, the intramolecular coupling is less, and in vivo stability is better than that found using the pentaester. (author)