The second method (II) was the fluorination of the protected precursor 1-(2 0 -nitro-1 0 -imidazolyl)-2-O-tetrahydropyranyl-3-O-toluenesulphonyl-propanediol, followed by a rapid removal of the protecting group. With the first method, the radiochemical yield was about 10% at the end of the synthesis (EOS), and the radiochemical purity was over 99%. The radiochemical yield in the second method was 21% (EOS) on an average, and the radiochemical purity was over 97%. When an automated commercial synthesis module was used with method II, slightly better and more reproducible yields were achieved. The improvement in the synthesis yield with the automated apparatus will be valuable when working with high activities, and therefore it is under further development.

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A synthesis method has been developed for the labelling of N‐(3‐[18F]fluoropropyl)‐2β‐carbomethoxy‐3β‐(4‐fluorophenyl)nortropane ([18F]β‐CFT‐FP), a potential radioligand for visualization of the dopamine transporters by positron emission tomography. The two‐step synthesis includes preparation of [18F]fluoropropyl tosylate and its use without purification in the fluoroalkylation of 2β‐carbomethoxy‐3β‐(4‐fluorophenyl)nortropane (nor‐β‐CFT). The final product is purified by HPLC. Optimization of the two synthesis steps resulted in a greater than 30% radiochemical yield of [18F]β‐CFT‐FP (decay corrected to end of bombardment). The synthesis time including HPLC‐purification was approximately 90 min. The radiochemical purity of the final product was higher than 99% and the specific radioactivity at the end of synthesis was typically 20 GBq/µmol. In comparison to alkylation by [18F]fluoropropyl bromide, the procedure described here results in an improved overall radiochemical yield of [18F]β‐CFT‐FP in a shorter time. Copyright © 2005 John Wiley & Sons, Ltd.

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A method based on autoradiography was developed to determine the sorption and diffusion of cesium, strontium, cobalt, nickel, iodine and americium into rock matrix. Samples chosen for this study were filled and unfilled natural fracture surfaces and drill cores having a central drilled hole (”). Rock types were mica gneiss, tonalite and rapakivi granite, which were selected to represent the common rocks and minerals in Finnish bedrock. Distribution coefficients (Ka-values) of cesium and strontium determined for fissure surfaces and drill core cups were of the same order of magnitude. After three months contact time the greatest penetration depth for cesium was 2.5 mm, for a natural fissure surface sample of rapakivi granite. For strontium the penetration depths of 11 mm in three months and 35 mm in twelve months were found for filled natural fissure surface samples of rapakivi granite. The range of Da-values was 1.5 × 10−15 - 3.2 × 10−14 m2/s and 1.4 × 10−14 - 2.1 × 10−13 m2/s for cesium and strontium, resp. For cobalt the Da-values of 5 × 1016 m2/s in tonalite was obtained. In six months the penetration depths of nickel, iodine and americium were too low (< 0.5 mm) to allow calculation of Da.