نتایج جستجو برای: attenuation correction

تعداد نتایج: 212408  

Journal: :Radiologic clinics of North America 2004
Adam M Alessio Paul E Kinahan Phillip M Cheng Hubert Vesselle Joel S Karp

PET/CT scanners offer a hardware solution for aligning and viewing functional and anatomic images that is immune to many of the errors in strictly software registration techniques. Moreover, PET attenuation-corrected emission scans benefit from the use of the onboard CT for fast, low-noise attenuation correction. Along with the significant improved localization and reduced acquisition time, PET...

2006
Steven E. Fick Dorea Ruggles

Radiation force balance (RFB) measurements of time-averaged, spatially-integrated ultrasound power transmitted into a reflectionless water load are based on measurements of the power received by the RFB target. When conical targets are used to intercept the output of collimated, circularly symmetric ultrasound sources operating at frequencies above a few megahertz, the correction for in-situ at...

2006
Alexander Ryzhkov David Hudak John Scott

A long-standing problem of attenuation correction at shorter weather radar wavelengths can be efficiently resolved by using measurements of differential phase ΦDP if the radar is polarimetrically upgraded. Original polarimetric method for attenuation correction by Bringi et al. (1990) stipulates that the ratio αh between specific attenuation Ah and specific differential phase KDP does not vary ...

Journal: :Journal of nuclear medicine technology 2016
Lee C Morris Marques L Bradshaw

Left ventricular assist devices (LVADs) provide the ability to maintain cardiac output and sustain life as a bridge to transplantation, definitive therapy, or a permanent decision. We present a case of LVAD drive infection that was differentiated from pump infection by the use of attenuation-corrected and non-attenuation-corrected CT, along with correlation with the planar images. Clinically, t...

Journal: :Annals of nuclear medicine 2002
Toru Kashiwagi Kenji Yutani Minoru Fukuchi Hitoshi Naruse Tadaaki Iwasaki Koichi Yokozuka Shinichi Inoue Shoji Kondo

Improvements in image quality and quantitation measurement, and the addition of detailed anatomical structures are important topics for single-photon emission tomography (SPECT). The goal of this study was to develop a practical system enabling both nonuniform attenuation correction and image fusion of SPECT images by means of high-performance X-ray computed tomography (CT). A SPECT system and ...

Journal: :Seminars in nuclear medicine 2003
Paul E Kinahan Bruce H Hasegawa Thomas Beyer

A synergy of positron emission tomography (PET)/computed tomography (CT) scanners is the use of the CT data for x-ray-based attenuation correction of the PET emission data. Current methods of measuring transmission use positron sources, gamma-ray sources, or x-ray sources. Each of the types of transmission scans involves different trade-offs of noise versus bias, with positron transmission scan...

Journal: :Journal of nuclear medicine technology 2006
Carlos A Garcia Giuseppe Esposito Elmo R Acio Douglas Van Nostrand

A 51-y-old man underwent (18)F-FDG PET for disease restaging of non-Hodgkin's lymphoma. Initial attenuation correction images demonstrated unilateral hemispheric cerebral hypometabolic activity. The remainder of the scan was otherwise unremarkable. Non-attenuation correction images demonstrated a patient motion artifact attributable to lateral movement of the patient's head during image acquisi...

Journal: :Journal of medical imaging 2014
Jinsong Ouyang Yoann Petibon Chuan Huang Timothy G Reese Aleksandra L Kolnick Georges El Fakhri

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...

2011
Lance T. Hall Aaron F. Struck Christopher G. Guglielmo Christine J. Jaskowiak Michael A. Wilson Scott B. Perlman

Purpose of Report: Evaluate the effect of IV contrast use with FDG PET/CT on clinical interpretation of PET images for head and neck cancer. Procedures: 20 consecutive patients referred for PET/CT and contrast enhanced CT of the head and neck had two sets of PET images obtained. One set used standard low dose CT for attenuation correction, and the other used IV contrast enhanced diagnostic qual...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2016
Yao Wu Wei Yang Lijun Lu Zhentai Lu Liming Zhong Meiyan Huang Yanqiu Feng Qianjin Feng Wufan Chen

Attenuation correction is important for PET reconstruction. In PET/MR, MR intensities are not directly related to attenuation coefficients that are needed in PET imaging. The attenuation coefficient map can be derived from CT images. Therefore, prediction of CT substitutes from MR images is desired for attenuation correction in PET/MR. METHODS This study presents a patch-based method for CT p...

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