A new method to measure regional CBF (rCBF) and volume of distribution of water is presented. It centres on recording the tissue build-up and retention of 15O-labelled water during the continuous ...inhalation of 15O-labelled carbon dioxide. Simultaneously, the arterial concentration is continuously monitored, and corrections for delay and dispersion in the recorded response are made by curve fitting. The values for the volume of distribution of water obtained in four normal subjects were close to reported in vitro values. Using the same fixed distribution volumes for both build-up and steady-state studies resulted in comparable rCBF values for both techniques.
The synthesis of 3-(2'-18Ffluoroethyl)spiperone (1c), a radiotracer useful for imaging the brain dopamine receptor system in vivo using positron emission tomography, is described. Precursors of 1c, ...the functional 3-N-alkyl derivatives of spiperone (4), were prepared by the alkylation of the amide group in spiperone (2a) by 1,2-disubstituted ethanes under phase transfer conditions. A comprehensive evaluation of the reaction of the derivatives 4a-h with no-carrier-added K18F/Kryptofix clearly indicated that the ketalized derivatives 4e-h were the choice of the precursors for 1c. The i.r., MS and NMR spectral data suggested that under phase transfer reaction conditions, the amide nitrogen was preferentially alkylated. To provide a firm basis for comparison with related analogues, an x-ray analysis was performed on a single crystal of 3-(2'-fluoroethyl)spiperone (1d). The tomographic behavior of 1c in human brain tissue was measured for more than 7 h and was consistent with the labeling of dopamine D-2 receptors.
The project of a large underground experiment,
N
OE
(Neutrino Oscillation Experiment), composed by modules of scintillating fiber calorimeter interleaved with TRD modules, total weight 6.7 ktons, is ...presented. This apparatus has been optimized for long baseline neutrino oscillation studies, in particular to be sensitive in the region of sin
2 2θ and
Δm
2 suggested by the atmospheric neutrino anomaly (fig. 3).
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