70 research outputs found

    Full-dose PET Synthesis from Low-dose PET Using High-efficiency Diffusion Denoising Probabilistic Model

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    To reduce the risks associated with ionizing radiation, a reduction of radiation exposure in PET imaging is needed. However, this leads to a detrimental effect on image contrast and quantification. High-quality PET images synthesized from low-dose data offer a solution to reduce radiation exposure. We introduce a diffusion-model-based approach for estimating full-dose PET images from low-dose ones: the PET Consistency Model (PET-CM) yielding synthetic quality comparable to state-of-the-art diffusion-based synthesis models, but with greater efficiency. There are two steps: a forward process that adds Gaussian noise to a full dose PET image at multiple timesteps, and a reverse diffusion process that employs a PET Shifted-window Vision Transformer (PET-VIT) network to learn the denoising procedure conditioned on the corresponding low-dose PETs. In PET-CM, the reverse process learns a consistency function for direct denoising of Gaussian noise to a clean full-dose PET. We evaluated the PET-CM in generating full-dose images using only 1/8 and 1/4 of the standard PET dose. Comparing 1/8 dose to full-dose images, PET-CM demonstrated impressive performance with normalized mean absolute error (NMAE) of 1.233+/-0.131%, peak signal-to-noise ratio (PSNR) of 33.915+/-0.933dB, structural similarity index (SSIM) of 0.964+/-0.009, and normalized cross-correlation (NCC) of 0.968+/-0.011, with an average generation time of 62 seconds per patient. This is a significant improvement compared to the state-of-the-art diffusion-based model with PET-CM reaching this result 12x faster. In the 1/4 dose to full-dose image experiments, PET-CM is also competitive, achieving an NMAE 1.058+/-0.092%, PSNR of 35.548+/-0.805dB, SSIM of 0.978+/-0.005, and NCC 0.981+/-0.007 The results indicate promising low-dose PET image quality improvements for clinical applications

    The Lantern Vol. 73, No. 1, Fall 2005

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    • Newspaper Clippings Found on the Wall of Giuseppe Luchenzo\u27s Home When it was Raided by Police • All the Time in the World • The Man Who Would Win • Souffle Suit • A Day in the Mind • Context • Felicity / Awareness • Frivolous • Thank You Note to J.S.B. • September 17, 2005 • Eight Ways of Looking at a Highway • Dusty Glass Spreads Air Like Light • Clockwork • Rubber Band • Outside Eye or I Am? • A Mundane Mysticism • Half Carat • Things I Learned on My Trip to the Mutter Museum of Medical Oddities • Peer Editing • The Attic Bones • Yeshttps://digitalcommons.ursinus.edu/lantern/1167/thumbnail.jp

    The Lantern Vol. 72, No. 2, Spring 2005

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    • Transmigration • Faces of the Moon • Euphony of the Euphonium • He Met Me in the Arcs & Ebbs of Frailty • An Adoration of Ordination • Ebony: The Essence Thereof • Curbside Statue Has No Legs Left • Triggerfinger Romance • Lost • Running Through Connecticut • Eve • The Day Lates and the Dollar Shorts • Somnambulist • That\u27s That • The Glenn Machine • Evenfall in Bad Homburg • Absence of Field • Dating Myself • Traveling Without a Map • The Non-Euclidean Way to Get Some Bagels • La Belle Epoque • Satin Boxeshttps://digitalcommons.ursinus.edu/lantern/1166/thumbnail.jp

    The Lantern Vol. 75, No. 2, Spring 2008

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    • In a French Courtyard at the Philadelphia Museum of Art • Picky Mangoes • And for My Un-Birthday I Drank Poets\u27 Tea and Got to See • Tree-Baby • Wrestling With Plants • I Smile • Walking Home • The Wall Between • Phalangese, or the Art of Speaking to Fingers • Early Spring • Karma Kids • A Bazaar Triptych • The Joys of Ritual Circumcision • [Of] Archetype[s] or I Don\u27t Like Your Poetry • Truth and Beauty Bombed • Chevalier Anachronistic • Kinds of Birds • Sparknotes Entry for The Changing Tide by Eric Relvas • Thirst • The Devil\u27s Dictionary • Portrait of an Artist Who Loves Icarus • Dinner at the Old House • The Meaning of a Dust-Busterhttps://digitalcommons.ursinus.edu/lantern/1172/thumbnail.jp

    The Lantern Vol. 73, No. 2, Spring 2006

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    • Of the Man • Beauty in America • Kindling • Genevieve • Bits of Copper • A Love Song to Hip Hop • From James\u27 Journal • I Want a Woman • Peregrine Rain • Resurge • Frustrations • (At Least) You Gave Me Something to Write About • The Fun of Giving Interactive History Lectures as a Summer Job • Exigence • White Water • My Summer, with Salt • The City With Two Faces • I Dig Your Cello • Life-Filled Ghost Town • Laura, On Happiness • Integration/Assimilation • Sunny Side Estates • Every Night I Shut My Eyes • New England State of Mind • Your Body\u27s Weight in Water for Your Soul, Thank You Very Much • A Story That\u27s 10 Percent Truehttps://digitalcommons.ursinus.edu/lantern/1168/thumbnail.jp

    Is it safe to perform cardiac catheterizations on adults with congenital heart disease in a pediatric catheterization laboratory?

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    Objective : To determine the complication rate during the catheterization in adults with congenital heart disease (CHD) in a pediatric catheterization laboratory (PCL). Background : An increasing number of patients with CHD are surviving into adulthood, with diagnostic and interventional cardiac catheterization being essential for the management of their disease. The complication rate during the catheterization of adults with CHD has not been reported. Methods : A retrospective chart review was performed on all adult patients (>18 years) with CHD who underwent diagnostic or interventional catheterization in our PCL within the past 8.5 years. Results : A total of 576 procedures were performed on 436 adult patients (median age 26 years). Complex heart disease was present in 387/576 (67%) procedures. An isolated atrial septal defect or patent foramen ovale was present in 115/576 (20%) procedures, and 51/576 (9%) procedures were performed on patients with structurally normal hearts with arrhythmias. Interventional catheterization was performed in 378/576 (66%) procedures. There were complications during 61/576 (10.6%) procedures; 19 were considered major and 42 minor. Major complications were death (1), ventricular fibrillation (1), hypotension requiring inotropes (7), atrial flutter (3), retroperitoneal hematoma, pneumothorax, hemothorax, aortic dissection, renal failure, myocardial ischemia and stent malposition (1 each). The most common minor complications were vascular entry site hematomas and hypotension not requiring inotropes. Procedures performed on patients ≥ 45 years of age had a 19% occurrence of complications overall compared with 9% occurrence rate in patients of age < 45 years ( P < 0.01). Conclusions : The complication rate during the catheterization of adults with CHD in a PCL is similar to the complication rate of children with CHD undergoing cardiac catheterization. The older subset of patients are more likely to encounter complications overall. The encountered complications could be handled effectively in the PCL. With screening in place, it is safe to perform cardiac catheterization on most adults with CHD in a PCL. © 2005 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48775/1/20537_ftp.pd

    Magnetic properties of ilmenite-hematite single crystals from the Ecstall pluton near Prince Rupert, British Columbia

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    Paleomagnetic studies of the 91 Ma Ecstall pluton and other Cretaceous plutons of British Columbia imply large northward tectonic movements (>2000 km) may have occurred during the tectonic evolution of western North America. However, more recent studies have shown that the eastern edge of the Ecstall pluton experienced considerable mineralogical changes as younger Eocene plutons, such as the ∼58 Ma Quottoon Pluton, were emplaced along its margins. We investigated changes in the rock magnetic properties associated with this reheating event by examining isolated grains of intergrown ilmenite and hematite, the primary paleomagnetic recorder in the Ecstall pluton. Measurements of hysteresis properties, low-temperature remanence, and room temperature isothermal remanent magnetization acquisition and observations from magnetic force microscopy and off-axis electron holography indicate that samples fall into three groups. The groups are defined by the presence of mineral microstructures that are related to distance from the Quotoon plutonic complex. The two groups closest to the Quottoon Pluton contain magnetite within hematite and ilmenite lamellae. Reheating of the Ecstall pluton led to an increase in coercivity and magnetization, as well as to development of mixed phase hysteresis. These results indicate that shallow paleomagnetic directions from the western Ecstall pluton are not affected by reheating and are therefore likely to record original field conditions at the time of pluton emplacement. In the absence of structural deformation, these shallow inclinations are consistent with large-scale northward translation suggested by the Baja–British Columbia hypothesis

    Rapid age-grading and species identification of natural mosquitoes for malaria surveillance

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    The malaria parasite, which is transmitted by several Anopheles mosquito species, requires more time to reach its human-transmissible stage than the average lifespan of mosquito vectors. Monitoring the species-specific age structure of mosquito populations is critical to evaluating the impact of vector control interventions on malaria risk. We present a rapid, cost-effective surveillance method based on deep learning of mid-infrared spectra of mosquito cuticle that simultaneously identifies the species and age class of three main malaria vectors in natural populations. Using spectra from over 40, 000 ecologically and genetically diverse An. gambiae, An. arabiensis, and An. coluzzii females, we develop a deep transfer learning model that learns and predicts the age of new wild populations in Tanzania and Burkina Faso with minimal sampling effort. Additionally, the model is able to detect the impact of simulated control interventions on mosquito populations, measured as a shift in their age structures. In the future, we anticipate our method can be applied to other arthropod vector-borne diseases
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