The novel PET radioligand (11)C-N,N-dimethyl-2-(2'-amino-4'-hydroxymethylphenylthio)benzylamine ((11)C-HOMADAM) binds with high affinity and selectively to the serotonin transporter (SERT). The purpose of this study was to develop a reliable kinetic model to describe the uptake of (11)C-HOMADAM in the healthy human brain.
Eight volunteers participated in the study; 5 of them were fitted with arterial catheters for blood sampling and all were scanned on a high-resolution research tomograph after the injection of (11)C-HOMADAM. Regional distribution volumes and binding potentials were calculated with 2- and 4-parameter arterial-input compartment models, a 3-parameter reference tissue compartment model, and the Logan graphic approach.
The 2-parameter arterial-input compartment model was statistically superior to the 4-parameter model and described all brain regions. Calculated binding potentials agreed well between the arterial-input model and the reference tissue model when the cerebellum was used as the reference tissue. The Logan graphic approach was not able to estimate the higher concentration of SERT in the dorsal raphe than in the midbrain.
(11)C-HOMADAM is a highly promising radioligand with high ratios of specific binding to nonspecific binding in known SERT-rich structures, such as the raphe nuclei. The 3-parameter reference tissue model approach permits a simplified quantitatively accurate method for estimating SERT binding potentials.
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"Conventional methods for kinetic parameter estimation define a region of interest (ROI) and estimate parameters based on the average. Such methods could be found in Lammertsma and Hume (1996), Slifstein et al. (2008) and Nye et al. (2008). However, conventional methods do not consider spatial heterogeneity. "
[Show abstract][Hide abstract] ABSTRACT: We present a fully Bayesian statistical approach to the problem of
compartmental modelling in the context of Positron Emission Tomography. We
cluster homogeneous region of interest and perform kinetic parameter estimation
simultaneously. A mixture modelling approach is adopted, incorporating both
spatial and temporal information based on reconstructed dynamic PET image. Our
modelling approach is flexible, and provides uncertainty estimates for the
estimated kinetic parameters. Crucially, the proposed method allows us to
determine the unknown number of clusters, which has a great impact on resulting
estimated kinetic parameters. We demonstrate our method on simulated dynamic
Myocardial PET data, and show that our method is superior to standard
[Show abstract][Hide abstract] ABSTRACT: The goal of the research presented in this paper is to identify
Pb-free alloys with melting temperatures close to or lower than that of
the near-eutectic 40Pb-60Sn solder (melting point of 183°C), and
that with the best mechanical properties. We have obtained substantially
improved mechanical properties through manipulation of alloy
microstructures. The following three alloys with superior mechanical
properties are discussed: i) Sn-3.5%Ag-1%Zn-0.5%Cu with a melting point
of ~216°C, ii) Sn-8%Zn-5%In-(0.1-0.5%)Ag with a melting point of
~187°C, and iii) 54.5%Bi-45%Sn-0.5%Ag with a melting point of
Electronics and the Environment, 1995. ISEE., Proceedings of the 1995 IEEE International Symposium on; 06/1995
[Show abstract][Hide abstract] ABSTRACT: In burst mode communication systems rapid carrier and clock
synchronization is essential. The authors propose a dedicated algorithm
for initial estimation of synchronization parameters in a PSK
demodulator which works in a single channel per carrier (SCPC) mode. The
algorithm is based on a very short special carrier preamble modulated by
a known pattern, which allows the reference parameters to be estimated
simultaneously and directly. The algorithm was implemented, together
with the whole PSK demodulator, on a Texas Instruments TMS320C31 digital
signal processor (DSP). Since the demodulator is entirely digital and
thanks to its implementation by means of low power VLSI technology it is
suitable for portable communication applications
Communications, 1995. ICC '95 Seattle, 'Gateway to Globalization', 1995 IEEE International Conference on; 07/1995