نتایج جستجو برای: mlem

تعداد نتایج: 102  

Journal: :Physics in medicine and biology 2015
Florian R Schneider Kenji Shimazoe Ian Somlai-Schweiger Sibylle I Ziegler

Silicon Photomultipliers (SiPM) are interesting light sensors for Positron Emission Tomography (PET). The detector signal of analog SiPMs is the total charge of all fired cells. Energy and time information have to be determined with dedicated readout electronics. Philips Digital Photon Counting has developed a SiPM with added electronics on cell level delivering a digital value of the time stam...

2013
Ai-guo Duan Jian-guo Zhang Xiong-qing Zhang Cai-yun He

The objective of this study was to introduce application of the Richards equation on modelling and prediction of stand diameter distribution. The long-term repeated measurement data sets, consisted of 309 diameter frequency distributions from Chinese fir (Cunninghamia lanceolata) plantations in the southern China, were used. Also, 150 stands were used as fitting data, the other 159 stands were ...

Journal: :Proceedings of SPIE--the International Society for Optical Engineering 2017
Yansong Zhu Abhinav K Jha Jakob K Dreyer Hanh N D Le Jin U Kang Per E Roland Dean F Wong Arman Rahmim

Fluorescence molecular tomography (FMT) is a promising tool for real time in vivo quantification of neurotransmission (NT) as we pursue in our BRAIN initiative effort. However, the acquired image data are noisy and the reconstruction problem is ill-posed. Further, while spatial sparsity of the NT effects could be exploited, traditional compressive-sensing methods cannot be directly applied as t...

Jalil Pirayesh Islamian, Parvaneh Darkhor Samira Abbaspour

Introduction: In nuclear medicine, the use of a pixelated semiconductor detector such as CZT is an of growing interest for introducing new devices. Especially, the spatial resolution can be improved by using a pixelated parallel-hole collimator with equal holes and pixel sizes based on the pixelated detector. The purpose of this study was to compare the effect of pixelated and ...

Journal: :Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics 2014
Navid Zeraatkar Salar Sajedi Mohammad Hossein Farahani Hossein Arabi Saeed Sarkar Pardis Ghafarian Arman Rahmim Mohammad Reza Ay

The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recov...

Introduction: There has been a curiosity about the spheroid geometry for PET scanners developments since several years ago, therefore in this study, we are aiming to evaluate the performance of this geometry and compare its performance with cylindrical geometry using Monte Carlo simulation. Methods: We simulated a spheroid geometry with a radius of 199 mm...

2006
P. Crespo F. Fiedler J. Pawelke G. Shakirin W. Enghardt

Due to its effectiveness in monitoring highly tumourconformed charged hadron therapy, in-beam positron emission tomography (in-beam PET [1]) is strongly desirable at charged hadron facilities under construction [2] or planning [3]. We present, therefore, optimized arrangements of the γ-ray detectors for next-generation in-beam PET scanners. A versatile, fully 3D, maximum likelihood expectation ...

Journal: :Physics in medicine and biology 2008
A S Kirov J Z Piao C R Schmidtlein

Correcting positron emission tomography (PET) images for the partial volume effect (PVE) due to the limited resolution of PET has been a long-standing challenge. Various approaches including incorporation of the system response function in the reconstruction have been previously tested. We present a post-reconstruction PVE correction based on iterative deconvolution using a 3D maximum likelihoo...

2007
D. Xu Z. He

In conventional Compton camera systems, the image reconstruction is performed only in two-dimensional or three-dimensional spatial coordinates for a specific gamma-ray energy. By doing so, a priori knowledge of the incident gamma-ray energy is required, and usually an energy window is applied to select full energy deposition events. In some other applications, spectral-deconvolution algorithms ...

Journal: :Physics in medicine and biology 2012
Lijun Lu Nicolas A Karakatsanis Jing Tang Wufan Chen Arman Rahmim

Standard 3D dynamic positron emission tomographic (PET) imaging consists of independent image reconstructions of individual frames followed by application of appropriate kinetic model to the time activity curves at the voxel or region-of-interest (ROI). The emerging field of 4D PET reconstruction, by contrast, seeks to move beyond this scheme and incorporate information from multiple frames wit...

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