Bio diesel fuel(BDF) was purified by column chromatography and the carbon 14(C-14) content was successfully measured by liquid scintillation counting(LSC). BDF was dissolved in hexane (10 wt%), and was purified by the column chromatography using an activated clay. Then the purified BDF was separated from hexane by evaporation under the boiling point of hexane. The purified BDF with toluene scintillator was measured by LSC. The biomass ratio obtained by LSC was in good agreement with that obtained by accelerator mass spectrometry.
18F-fluoride ion(18F-NaF)first introduced by Blau in 1962 was approved in 1972 by the FDA, and 99mTc-diphosphonate becomes the standard bone imaging radiopharmaceutical, with bone scintigraphy performed more than 430000 times a year in Japan. High resolution, high sensitivity and multi-slice PET device appeared from the first half of the 1990's, and systemic three dimensional tomograms became easily obtainable, making it possible for bone PET to search for systemic bony lesions within a short time. In the Japanese Society of Nuclear Medicine Working Group, we evaluated bone PET and PET/CT as compared with bone scintigraphy in three institutions during a two-year period to determine the clinical usefulness and cost effectiveness of bone PET and PET/CT. Bone PET and PET/CT showed a significant superiority over bone scintigraphy in 67 patients with lytic and sclerotic malignant and benign lesions. We consider based on other studies and our results that bone PET and PET/CT will become routine bone imaging modalities in future.
Tritium enrichment is a important determination method of the tritium concentration in an environmental water. However, more advanced method is required because the tritium separation factor (βa) obtained by the electrolysis using solid polymer electrolyte membrane (SPE electrolysis method) is not so large. We therefore focused on effects of magnetic field and temperature on electrolysis enrichment, and carried out some experiments as below. The electrolysis cell of the electrolysis-apparatus based on the SPE electrolysis method was set as follows:the direction of electrolysis current was set at right angle (orthogonal condition) to the magnetic field. Then the electrolysis was carried out at both a magnetic flux density in the range of 0-5T and a constant temperature in the range of 25-35°C. Consequently, the followings have been clarified. (1)βa is affected by the magnetic field at the orthogonal condition. (2)βa increases with increasing the magnetic field (0-4T). (3)Both the magnetic field and the temperature affect βa in the orthogonal condition. (4)The effect of temperature on βa may relate to the influence of the magnetic field and the temperature dependence of the dissociation of HTO.
Chinese nuclear medicine has 53 years history since 1956, and now is spreading in the country with the development of economy. Positron emission tomography(PET)has a rapid development in China, especially in the application of oncology, neurological and cardiologic diseases. The research of molecular imaging including PET also has been initiated. Zhejiang University as the largest university in China, has established the center of excellence in molecular imaging to improve the development of molecular imaging, which has active partnership and collaborative relationship with Japan, USA and European countries. The future of molecular imaging including PET in China is bright.
Imaging has been used as an effective research tool in many fields. In recent years, “molecular imaging” has come to attract a major attention as it studies molecular events in living animals and humans. Variety of modalities is used in molecular imaging, sometimes in combination, and the machines and techniques are going through rapid progress. Two of popular modalities among them are fluorescence imaging and radioisotope (RI) imaging such as positron emission tomography (PET) and single photon emission tomography (SPECT). Fluorescence imaging provides rich selection in imaging probes and the resolution can reach into sub-cellular level. RI imaging, especially PET, is superior to the others in quantitative analysis and the direct applicability to humans. In this article the two imaging modalities are overviewed comparing their characteristics.
11C-L-methionine (MET) is the most popular PET tracer for amino acid imaging of neoplastic disease. Amino acid metabolism of cancer is associated with numerous metabolic processes favoring tumor growth. L-methionine, an essential amino acid, plays a central role in the altered metabolism of cancer cells. Specially, increased uptake of MET as measured by PET has been suggested to reflect increased transport, transmethylation rate, and protein synthesis of malignant tissue, and has less influence of radiation-induced inflammatory reaction after radiotherapy. This article discusses the role of MET-PET in imaging of brain, head and neck, chest, pelvis and other part of body. The role of MET-PET in clinical management of patients with cerebral gliomas, head and neck cancer, lung cancers, ovarian tumors, uterine carcinomas, rectal cancers, malignant melanomas, multiple myelomas or bone and soft tissue tumors is reviewed in detail. In summary, MET-PET has a high sensitivity and specificity in detecting some malignant tumors. Statistically significant differences in MET uptake have been demonstrated between high- and low-grade gliomas. Patients with a lower MET uptake has been associated with a better prognosis even if patients have the same grade glioma. The feasibility and usefulness of MET-PET for therapy assessment and follow-up after therapy have demonstrated. MET-PET appears to have a high sensitivity and specificity in differentiating recurrent brain tumor from radiation injury. MET-PET has shown its usefulness in initial diagnosis, tumor-extent delineation, biopsy planning, radiotherapy planning, assessment of response to therapy and some other clinical management of cancer patients.