نتایج جستجو برای: positron
تعداد نتایج: 31378 فیلتر نتایج به سال:
In this paper, we first study the conditions for the existence of the solitonic solutions in ion-electron-positron plasma. Then we investigate the effect of increasing positron on the solitonic wave properties, We also consider the time evolution of these waves in passing through the boundaries of two plasma with different positron densities and different positron-electron temperature ratios.
Introduction Range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (PET). In this study, GEANT4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in PET imaging including 11C, 13N, 15O, 18F, 68Ga, and 82Rb. Materials and Methods GEA...
Positron annihilation lifetime spectroscopy method with valuation of non-destructive investigation of material, provides information about electron density, defect concentration, type of defects and atoms around the defects. The stability of the system was tested with a source. The time resolution of the whole system has been derived about 365 ps at FWHM. Then n- and p-type silicon samples we...
introduction range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (pet). in this study, geant4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in pet imaging including 11c, 13n, 15o, 18f, 68ga, and 82rb. materials and methods gea...
combined pet/ct scanners now play a major role in medicine for in vivo imaging in oncology, cardiology, neurology, and psychiatry. as the performance of a scanner depends not only on the scintillating material but also on the scanner design, with regards to the advent of newer scanners, there is a need to optimize acquisition protocols as well as to compare scanner performances on an objective ...
as a nuclear approach, positron emission tomography (pet) is a functional imaging technique which is based on the detection of gamma ray pairs emitted by a positron-emitting radionuclide. there are certain limitations to this technique such as normal tissue uptake. therefore, it has been recommended that patients prepare before scanning. fasting for a short while before pet imaging is an exampl...
introduction while primary malignant tumors of the heart are rare, angiosarcomas are the most common cardiac malignant tumors. case presentation we describe a 23-year-old woman who presented with a right atrial mass, which was discovered to be a cardiac angiosarcoma. we demonstrate the use of several noninvasive imaging modalities along with pathology confirmation for the definitive and compreh...
PET (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (PET radiopharmaceuticals) in the body. Positrons (ß+) are positively charged beta particles. They are emitted when the atom is proton rich. A positron has only a transient existence. After losing all of its kinetic ene...
PET (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (PET radiopharmaceuticals) in the body. Positrons (ß+) are positively charged beta particles. They are emitted when the atom is proton rich. A positron has only a transient existence. After losing all of its kinetic ene...
pet (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (pet radiopharmaceuticals) in the body. positrons (ß+) are positively charged beta particles. they are emitted when the atom is proton rich. a positron has only a transient existence. after losing all of its kinetic ene...
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