نتایج جستجو برای: positron

تعداد نتایج: 31378  

محسن سربیشه‌ای, , مرضیه متقی‌زاده, , پروین اسلامی, ,

  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.

Ali Asghar Mowlavi, Mohsen Mashayekhi

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...

جعفرزاده خطیبانی, مرتضی, خاقانی, مرتضی , طیب‌فرد, اسماعیل , مهمان دوست خواجه‌داد, علی‌اکبر , پورصالح, علی‌محمد ,

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...

Journal: :iranian journal of medical physics 0
ali asghar mowlavi physics department, hakim sabzevari university, sabzevar, iran. international centre for theoretical physics (ictp), associate and federation schemes, medical physics field, trieste, italy.

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...

Journal: :iranian journal of nuclear medicine 2009
parham geramifar mohammad reza ay mojtaba shamsaie zafarghandi george loudos arman rahmim

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 ...

Journal: :journal of fasting and health 0
elham dolat medical physics research center, mashhad university of medical sciences, mashhad, iran ameneh sazgarnia medical physics research center, mashhad university of medical sciences, mashhad, iran

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...

Journal: :archives of cardiovascular imaging 0
roy beigel the heart institute, cedars sinai medical center, david geffen school of medicine, ucla joao carlos tress hospital universitario pedro ernesto louise elizabeth jane thomson the heart institute, cedars sinai medical center, david geffen school of medicine, ucla daniel james luthringer department of pathology, cedars sinai medical center, david geffen school of medicine alexander shturman department of cardiovascular medicine, western galilee hospital, bar ilan university alfredo trento the heart institute, cedars sinai medical center, david geffen school of medicine, ucla

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...

Journal: :the iranian journal of pharmaceutical research 0
soraya shahhosseini

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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