نتایج جستجو برای: attenuation emission data
تعداد نتایج: 2593617 فیلتر نتایج به سال:
Abstract We use Paschen- β (Pa ; 1282 nm) observations from the Hubble Space Telescope G141 grism to study star formation and dust-attenuation properties of a sample 29 low-redshift ( z < 0.287) galaxies in CANDELS Ly α Emission at Reionization survey. first compare nebular attenuation Pa /H with stellar inferred spectral energy distribution, finding that our are consistent an average ratio ...
Myocardial perfusion studies suffer from artifacts caused by misalignment of the transmission and emission data due to the influences of voluntary and involuntary patient motion. Regardless of 68Ge or respiratory-averaged CT based attenuation correction and good patient cooperation, approximately 21% of perfusion studies exhibit artifacts arising from misalignment that cannot be corrected by ma...
A 68-year–old woman had been experiencing Raynaud symptom, palpitation of the heart, and short breath in walking stairs or slopes for 7 years. Recently, these symptoms had rapidly become worse. She admitted to our hospital. At that time, she was diagnosed with systemic scleroderma (limited scleroderma). Pulmonary hypertension was pointed out by echocardiography (estimated pulmonary artery press...
Rhizophora wood exhibits characteristics of interaction with radiation similar to those of water. Recently, a novel model based on MCNP4C code has been proposed for calculation of mass attenuation coefficients for some polymers. The aim of this study is to determine the mass attenuation coefficients for Rhizophora wood in energy range 15.77-60 keV using this model. First, the mentioned model wa...
Iterative reconstruction algorithms produce accurate images without streak artifacts as in ®ltered backprojection. They allow improved incorporation of important corrections for image degrading effects, such as attenuation, scatter and depth-dependent resolution. Only some corrections, which are important for accurate reconstruction in positron emission tomography and single photon emission com...
In combined PET/MR, the high soft tissue contrast of Magnetic Resonance Imaging (MRI) and the functional information of Positron Emission Tomography (PET) are combined in one machine. Although this combination still poses many technological challenges, recent progress [1] indicates that it is only a matter of time before PET/MR machines enter the market. On the software side, attenuation correc...
Simultaneous positron emission tomography and magnetic resonance imaging (PET-MR) is an innovative and promising imaging modality that is generating substantial interest in the medical imaging community, while offering many challenges and opportunities. In this study, we investigated whether MR surface coils need to be accounted for in PET attenuation correction. Furthermore, we integrated moti...
The aim of this study was to examine the angular distribution of the light emitted from radiation-excited scintillators in medical imaging detectors. This distribution diverges from Lambert's cosine law and affects the light emission efficiency of scintillators, hence it also affects the dose burden to the patient. In the present study, the angular distribution was theoretically modeled and was...
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