Vol.12,

The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original image voluminal data were acquired with a CT scanner, MR and dual-head coincidence SPECT, respectively. The data sets from all imaging devices were queried, retrieved, transferred and accessed via DICOM PACS. The image fusion was performed at the SPECT ICON work-station, where the MIM (Medical Image Merge) fusion software was installed. The images were created by reslicing original volume on the fly. The image volumes were aligned by translation and rotation of these view ports with respect to the original volume orientation. The transparency factor and contrast were adjusted in order that both volumes can be visualized in the merged images. The image volume data of CT. MR and nuclear medicine were transferred, accessed and loaded via PACS successfully. The perfect fused images of chest CT/¹⁸F-FDG and brain MR/SPECT were obtained. These results showed that image fusion technique using PACS was feasible and practical. Further experimentation and larger validation studies were needed to explore the full potential of the clinical use.

473

The effectiveness of using some ratios in ^99mTc-MIBI imaging for the diagnosis of breast tumors was evaluated. After 100 patients with the breast tumor underwent ^99mTc-MIBI imaging, the ratios of tumor to contralateral uptake (T/N). tumor to heart uptake (T/H), and tumor to sternum uptake (T/S) were obtained and then analysed about their reproducibility and values in differentiating benign breast lesion the from malignant tumor. To detect breast cancers, the sensitivity, specificity and accuracy of T/N were 92%, 90% and 91%, respectively. However, those of T/S were 70% (p<0.01), 74% (p<0.05), 72% (p<0.01), and those of T/H were 74% (p<0.05), 76% (p>0.05), 75% (p<0.01). The average coefficients of variation(CV) of T/N. T/S and T/H were 9.439±9.712, 4.856±4.420 (p>0.05), and 3.736±3.489 (p<0.05). It was found that T/N had the best sensitivity, specificity and accuracy to detect the breast cancer, but its reproducibility is poor. On the other hand. T/H has better reproducibility.

401

The aim of this study was to establish a model by single injection of Aβ_1-40+IA into rat brain basal ganglion and examine the effect of ZDY101, an active component of a Yin tonic from Chinese traditional medicinal herb. The results showed that the amnestic effect of co-injection of Aβ and IA lasted for at least 2 months. At same time, the total M-receptor density in model brain was significantly lower than blank control, indicating the change is profound enough for long term pathological studies or drug screening. It can be clearly seen that the decreased brain M-receptor density caused by Aβ was significantly increased by ZDY101. Such an elevation effect was significantly correlated with dose of ZDY101 when the dose was examined in a certain reasonable range. It can also be clearly seen that such an elevation of M-cholinergic receptor density was significantly correlated with the improvement of memory which indicated that the increase of M-cholinergic receptor density was an important factor in improving the memory of such animal model.

532

To prepare ^125/131I-β-CIT (2β-carbomethoxy-3β- (4-iodophenyl)tropane as an imaging agent for dopamine transporter (DAT), the labeling method from tributylstannyl precursor with peracetic acid has been reported in this article. The radiochemical purity (RCP) of the labeled compound was over 95% determined by HPLC and TLC. The stability, partition coefficients were also determined. The pharmacological studies of the imaging agent were performed in rats, mice, rabbits and normal monkey. The ligand showed preferable uptake in brain (1.9%ID/organ in rats and 4.5%ID/organ in mice at 5 min). The ratios of striatum/cerebellum. hippocampus/cerebellum and cortex/cerebellum were 28.9. 3.97 and 4.75 at 6h in rats, and 8.52. 2.99 and 3.06 at 6h in mice, respectively. In monkey brain imaging the ratios of striaturn/frontal cortex (ST/FC) and striatum/occipital cortex (ST/OC) were 5.14 and 5.97 at 4h, respectively. All of above showed the high affinity of the ligand to DAT. The compound was primarily metabolized in liver because the hepatic uptake was much higher than other organs (75.4%ID/organ at 18h). The half-life of blood elimination was 5 min. The dose received by mice was 2500 times as high as that received by human in the test of undue toxicity, which evaluated the safety of the agent. All the results suggest that β-CIT can be used as a potential DAT imaging agent.

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The author indicates that even a conclusive confirmation of neutrino oscillation does not necessarily imply the existence of massive neutrinos. The negative value of neutrino mass-square may be an alternative key with realistic physical meaning. Reexamining special relativity (SR) we find that there actually exists a formal phase velocity of "de Broglie's wave" in temporal Lorentz transformation attributed to the intrinsical essence of Minkowski's space. The properties of spacelike interval between two events have already included constrains to describe superluminal motion and SR is compatible with the faster-than-light motion originally in algebraic domain. Pay attention to that the operator representation, p→↔−iℏ∇→. has just verified for subluminal particles, not for superluminal particles, adhering to de Broglie's coexistence idea between waves and particles, it is possible to deduce a formal two-component Weyl equation to describe any species of free neutrinos with imaginary rest mass, which is equivalent to making use of the Dirac equation for a free spin-1/2 particle with zero rest mass in form.

497

60 MeV/u ¹⁸O ions were used to bombard natural uranium targets, and the heavy neutron-rich isotope ²³⁷Th was produced via multi-nucleon transfer reaction and dissipative fragmentation of the heavy target. A relatively fast radiochemical procedure was used to separate thorium from the mixture of uranium and complex reaction products. The chemically separated thorium fractions were studied by the γ-ray spectroscopic method. The behaviors of the growth and decay of 853.7 and 865.0 keV γ rays of ²³⁷Pa decay were observed. The half-life of ²³⁷Th was determined to be 4.69±0.60 min.

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The influence of the high temperature processing on the strain stored in SiGe hetero epilayer was studied by means of RBS/Channeling. Channeling angular scan along the < 110 > axial direction in the (100) plane was used to characterize the tetragonal distortion in the SiGe strained layer. The strained crystal structure parameters were acquired by combining the determination of strain with the elasticity theory. It is shown that the strain stored in the SiGe epilayer has significantly change (relaxation factor from 0.023 to 0.84) after high temperature annealing. The potential strain relaxation mechanisms were discussed.

356

To improve nuclear fuel utilization efficiency and prolong fuel cycle burn-up, a tight pitch lattice pressured heavy water reactor was investigated as an alternative of next generation of power reactors. It is shown that the high conversion ratio and negative coolant void reactivity coefficient are challenges in the reactor core physics designs. Various techniques were proposed to solve these problems. In this work, a tight pitch lattice and mixed fuel assemblies pressured heavy water reactor concept was investigated. By utilizing numerical simulation technique, it is demonstrated that reactor core mixed with Pu/U and Th/U assemblies can achieve high conversion ratio (0.98), long burn-up (60 GWD/t) and negative void reactivity coefficients.

391

The dynamical behavior of the subcooled boiling two-phase system was introduced and discussed. With the introduction of fractal concept, an analysis of the fractal feature of pressure wave signals from nonlinear dynamics point of view, was carried out. Meanwhile, the pseudo phase diagrams of typical time series of sound pressure were given. Finally, through dynamic clustering and on the basis of calculating correlation dimension and Hurst exponent of pressure wave time series on different subcooling conditions, the recognition of developing regime of the two-phase system was delivered, which might provide a promising approach of recognition and diagnosis of a boiling system.

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