28,184 research outputs found
Going beyond the borders : field-of-view extension in MR/PET hybrid imaging
No full textThe recent combination of Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) is of emerging interest in clinical routine. On the one hand, MRI is a widely-used diagnostic tool in medical practice. The excellent soft-tissue contrast offers reliable anatomical information. On the other hand, PET is a key imaging technique in nuclear medicine. It shows the functional metabolism thus providing information on the biochemical and physiological processes of the patient. The recently developed MR/PET hybrid system combines these advantages in one whole-body system.
The integration of the PET detector in an MR system is a new challenge. In particular, new concepts for the attenuation correction of the PET data are
required. This attenuation correction can be performed based on the MR data. However, the MR field-of-view (FoV) is limited by intrinsic physical restrictions such as B0 inhomogeneities and gradient nonlinearities. It has been reported that the PET quantification is biased due to the limitation of the MR-based FoV. Thus, new acquisition techniques are required for imaging beyond the FoV limitation. This was addressed in this thesis.
A novel method was developed to compensate the distortions arising from the gradient nonlinearity and the B0 inhomogeneity by using an optimal gradient amplitude. This imaging technique was implemented in a spin-echo-based sequence featuring multi-slice acquisition, bipolar readout and continuous table movement. Thereby, an extension of the FoV was achieved. The optimal sequence parameters were determined inline and applied automatically. No further user interaction or hardware modifications were required. The additional acquisition time is easily tolerable for clinical routine.
In a patient study the improvement achieved by the proposed method was verified. The reported bias in the PET reconstruction was reduced significantly. Therefore, the proposed technique improves the MR-based attenuation correction of the PET emission data. Furthermore, the achieved FoV extension might be of interest for diverse MR applications such as image-guided therapy or measuring of large patients. In summary a method has been developed that improves the PET quantification in MR/PET hybrid imaging
Mr. Melvin J. Collier, RWWL AUC, June 2011
No full textThis video is a conversation with Mr. Melvin J. Collier. Mr. Collier talks about his book, "From Mississippi to Africa: A Journey of Discovery". Daniel Le, AUC Woodruff Library, is the interviewer
Bonnevie, Bo Tørris (Mr)
No full textDepartment of Zoology and Entomology Bo Tørris Bonnevie ORCID 0000-0002-5906-9577 Top 30 Rhodes Researchers 2010</a
Cohomology of with local integer coefficients
No full textsummary:Let \Cal Z be a set of all possible nonequivalent systems of local integer coefficients over the classifying space . We introduce a cohomology ring \bigoplus_{\Cal G\in \Cal Z} H^*(BO(n_1)\times \dots \times BO(n_m);\Cal G), which has a structure of a -graded ring, and describe it in terms of generators and relations. The cohomology ring with integer coefficients is contained as its subring. This result generalizes both the description of the cohomology with the nontrivial system of local integer coefficients of in [Č] and the description of the cohomology with integer coefficients of in [M]
Interview Excerpt of Mr. Donald M. Crawford, Sr.
No full text(1948-2018) Donald Mitchell Crawford, Sr. (“DC”), musician, author, and educator, was born on May 24, 1948, and was a lifelong resident of Birmingham, AL. His father and mother owned and operated “C & S Charter Tours Bus Company,” the first black-owned bus company in the state of Alabama. Crawford was a 1966 graduate of Western Olin High School in Birmingham, AL. Crawford was an outstanding drum major, playing first chair alto saxophone under the tutelage of the late Amos F. Gordon, Sr. After high school, he received a music scholarship to Alabama State University (ASU) where he earned both his Bachelor’s and Master’s Degrees in Music Education and was later inducted into the “School of Music Hall of Fame” at ASU. He was the youngest ever inducted into the Alabama Jazz Hall of Fame. He was a veteran of the U.S. Army and performed with the 291 st and 283rd Army Band in Fort Bennett, GA. DC was Band Director at Jackson Olin High School and taught in the Birmingham School System for over thirty-five years. His love for music and performing lead him after his retirement to serve as Band Director for Miles College.
Crawford is the author of “The Wheels of the Birmingham Civil Rights Movement.” This book chronicles the lives of his late father and mother, Worcy and Christine Pride Crawford, and the role he and the company played in the Birmingham Civil Rights Movement
Bo Oberhansly
No full textBo Oberhansly, son of Mr. and Mrs. Marc Oberhansly of Neola, was called to serve a mission for the Church of Jesus Christ of Latter-day Saints in the Rapid City, South Dakota mission
Scatter effects of MR components in PET-MR inserts
No full textSystem design research for upcoming PET-MR scanners has mainly focussed on the effect of the high magnetic field on PET performance and on the influence of the PET scanner inside the MR bore on MR image quality. However, the presence of MR components close to the PET detectors could also have an influence on PET performance. We have investigated these effects in a simulation study of the preclinical PET-MR insert and of the proposed integrated whole-body system of the HYPERimage project. Simulations were performed with the ProcessGATE extension of the GATE simulation framework, which makes it possible to determine the fractions of total scatter caused by different components. The preclinical insert was simulated inside a clinical MR scanner. All components of the clinical system and the preclinical insert were modeled in realistic dimensions and materials. The PET detector consisted of 10 detector blocks on a 100 mm radius cylinder, each containing a 44 (tangential) by 72 (axial) array of LYSO crystals. The crystal dimensions were 1.3 * 1.3 * 10 mm. The energy window was set to 250 - 750 keV. The integrated whole-body system was modeled as the same clinical MR system with a split gradient coil and PET detector blocks between both parts of the split gradient coil. The PET detector blocks in the whole-body system consisted of 22 detector blocks on a 35 cm radius cylinder containing 22 (tangential) by 43 (axial) LYSO crystals. The crystal dimensions were 4 * 4 * 22 mm. The energy window in this configuration was 410 - 700 keV. A uniform cylinder (radius 5 mm, length 100 mm) filled with 1 MBq of 18F was simulated in both the preclinical insert and the whole-body system. The simulated time was 1s yielding one million simulated decays. In the preclinical insert only 47 % of detected singles were unscattered. The clinical system and precinical insert accounted for respectively 38 % and 15 % of scattered photons. On the coincidences level the influence of the clinical system was much smaller (17 %), while the scatter effect of the insert increased (20%). In the clinical system the gradient coils scatter the largest fraction of photons (58 %). In the insert over 65 % of scatter is caused by the table and the RF screen. In the integrated whole-body system 44 % of detected singles were scattered. At coincidence level this fraction was reduced to 34 %. The largest amount of scattered coincidences is caused by the RF screen. In conclusion, it is clear that putting MR components within or close to the FOV of a PET scanner can cause significant scatter. The scattering effect of the MR components should be taken into account in the design phase
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.On p. 1: Anecdote of Cromwell.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.P. 1 contains an 'Anecdote' beginning "A certain nobleman, .. ".Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Interesting anecdotes, memoirs, allegories, essays, and poetical fragments, [electronic resource] : tending to amuse the fancy, and inculcate morality. By Mr. Addison.
No full textMr. Addison is a pseudonym.On p. 1: Anecdote of Doctor Young.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
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