نتایج جستجو برای: mlem

تعداد نتایج: 102  

2004
David S.C. Biggs Zhiping Mu Yupeng Zhang Timothy J. Holmes Alexey Khodjakov Shinya Inoué

Image deconvolution has been widely used in optical microscopy to improve image resolution and enhance contrast, mainly for 3D optically sectioned images. 2D images can be deconvolved in a similar way, and in many circumstances, such processing is either necessary or sufficient. Confocal microscope image slices can be processed as 2D images, especially if the pinhole is opened slightly to incre...

Journal: :Physics in medicine and biology 2016
Abolfazl Mehranian Fotis Kotasidis Habib Zaidi

Time-of-flight (TOF) positron emission tomography (PET) technology has recently regained popularity in clinical PET studies for improving image quality and lesion detectability. Using TOF information, the spatial location of annihilation events is confined to a number of image voxels along each line of response, thereby the cross-dependencies of image voxels are reduced, which in turns results ...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2005
Youngho Seo Kenneth H Wong Mingshan Sun Benjamin L Franc Randall A Hawkins Bruce H Hasegawa

UNLABELLED (111)In-Capromab pendetide imaging is indicated for postprostatectomy patients at risk for residual or recurrent disease. However, this study is complicated by relatively long times for tumor uptake and background washout that require imaging to be performed several days after radiopharmaceutical administration. In addition, (111)In-capromab pendetide demonstrates uptake in normal st...

Journal: :Physics in medicine and biology 2013
Meredith K Kupinski Eric W Clarkson Harrison H Barrett

In tomographic medical imaging, a signal activity is typically estimated by summing voxels from a reconstructed image. We introduce an alternative estimation scheme that operates on the raw projection data and offers a substantial improvement, as measured by the ensemble mean-square error (EMSE), when compared to using voxel values from a maximum-likelihood expectation-maximization (MLEM) recon...

Journal: :iranian journal of radiation research 0
a. vahidian kamyad department of mathematic, ferdowsi university, mashad, iran m.h. noori eskandari department of mathematic, ferdowsi university, mashad, iran m. naji midani department of medical physics, mashad university for medical sciences, mashad, iran m. hajizadeh saffar department of medical physics, mashad university for medical sciences, mashad, iran

background: photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of spect images and results to errors in accuracy of quantitative measurements. this can be corrected via different physical or mathematical approaches. as the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘piece wise line...

دستگاه تصویربرداری گسیل پوزیترون برای تشخیص تغییرات فیزیولو‍‍‍ژیک بدن استفادها می شود. بنابراین هدف اصلی در مطالعات پت، به‌دست آوردن تصاویر با کیفیت خوب و جزئیات فانتومی است که به‌وسیلة پت تصویربرداری شده است. کارایی دستگاه پت و در‌نتیجه کیفیت تصویر خروجی، به پارامترهای قدرت تفکیک مکانی، کسر پراکندگی، حساسیت، RMS کنتراست و سیگنال به نویز بستگی دارد، که دستگاه بر‌اساس آن ارزیابی می شود. در این م...

A. Vahidian Kamyad, M. Hajizadeh Saffar, M. Naji Midani, M.H. Noori Eskandari,

Background: Photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of SPECT images and results to errors in accuracy of quantitative measurements. This can be corrected via different physical or mathematical approaches. As the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘Piece ...

Journal: :Physics in medicine and biology 2007
M Reyes G Malandain P M Koulibaly M A González-Ballester J Darcourt

In emission tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity...

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