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Current methods for magnetic resonance-based positron emission tomography attenuation correction (PET-MR AC) are time consuming, and less able than computed tomography (CT)-based AC methods to capture inter-individual variability and skull…

Quantitative PET attenuation correction (AC) for combined cardiac PET/MR is a challenging problem. We propose and evaluate an AC approach that uses coincidences from a relatively weak and physically fixed sparse external source, in…

Medical Physics · Physics 2023-01-02 Mi-Ae Park , Vlad G. Zaha , Ramsey D. Badawi , Spencer L. Bowen

In computed tomography (CT) reconstruction, scattering causes server quality degradation of the reconstructed CT images by introducing streaks and cupping artifacts which reduce the detectability of low contrast objects. Monte Carlo (MC)…

Image and Video Processing · Electrical Eng. & Systems 2022-02-01 Ammar Alsaffar , Steffen Kieß , Kaicong Sun , Sven Simon

Deep convolutional neural networks (DCNN) have demonstrated its capability to convert MR image to pseudo CT for PET attenuation correction in PET/MRI. Conventionally, attenuated events are corrected in sinogram space using attenuation maps…

Computer Vision and Pattern Recognition · Computer Science 2019-05-22 Jaewon Yang , Dookun Park , Jae Ho Sohn , Zhen Jane Wang , Grant T. Gullberg , Youngho Seo

Accurate quantification in positron emission tomography (PET) is essential for accurate diagnostic results and effective treatment tracking. A major issue encountered in PET imaging is attenuation. Attenuation refers to the diminution of…

In medical SPECT imaging, we seek to simultaneously obtain the internal radioactive sources and the attenuation map using not only ballistic measurements but also first order scattering measurements. The problem is modeled using the…

Analysis of PDEs · Mathematics 2015-09-02 Matias Courdurier , Francois Monard , Axel Osses , Francisco Romero

Purpose: To develop a model-based deep neural network for high-quality image reconstruction of undersampled multi-coil chemical exchange saturation transfer (CEST) data. Theory and Methods: Inspired by the variational network, the CEST…

Medical Physics · Physics 2023-05-26 Jianping Xu , Tao Zu , Yi-Cheng Hsu , Xiaoli Wang , Kannie W. Y. Chan , Yi Zhang

Photoacoustic (PA) computed tomography (PACT) shows great potentials in various preclinical and clinical applications. A great number of measurements are the premise that obtains a high-quality image, which implies a low imaging rate or a…

Computer Vision and Pattern Recognition · Computer Science 2021-06-01 Hengrong Lan , Juze Zhang , Changchun Yang , Fei Gao

Spectral Photon-Counting Computed Tomography (SPCCT) is a promising technology that has shown a number of advantages over conventional X-ray Computed Tomography (CT) in the form of material separation, artefact removal and enhanced image…

Image and Video Processing · Electrical Eng. & Systems 2020-03-10 Dimitris Kamilis , Mario Blatter , Nick Polydorides

Spectral graph contrastive learning often constructs low- and high-frequency views to capture complementary graph signals, but these views are commonly combined by graph-level or node-agnostic fusion rules. We show that graph-level fusion…

Machine Learning · Computer Science 2026-05-11 Zhuolong Li , Boxue Yang , Haopeng Chen

Due to its wide field of view, cone-beam computed tomography (CBCT) is plagued by large amounts of scatter, where attenuated photons hit the detector, and corrupt the linear models used for reconstruction. Given that one can generate a good…

Medical Physics · Physics 2017-07-06 Jonathan Mason , Alessandro Perelli , William Nailon , Mike Davies

Perceptual losses have emerged as powerful tools for training networks to enhance Low-Dose Computed Tomography (LDCT) images, offering an alternative to traditional pixel-wise losses such as Mean Squared Error, which often lead to…

Computer Vision and Pattern Recognition · Computer Science 2025-10-01 Gabriel A. Viana , Luis F. Alves Pereira , Tsang Ing Ren , George D. C. Cavalcanti , Jan Sijbers

Diffusion models have been demonstrated as powerful deep learning tools for image generation in CT reconstruction and restoration. Recently, diffusion posterior sampling, where a score-based diffusion prior is combined with a likelihood…

Medical Physics · Physics 2024-09-02 Shudong Li , Xiao Jiang , Matthew Tivnan , Grace J. Gang , Yuan Shen , J. Webster Stayman

Deep learning-based reconstruction of positron emission tomography(PET) data has gained increasing attention in recent years. While these methods achieve fast reconstruction,concerns remain regarding quantitative accuracy and the presence…

In positron emission tomography (PET), it is indispensable to perform attenuation correction in order to obtain the quantitatively accurate activity map (tracer distribution) in the body. Generally, this is carried out based on the…

Medical Physics · Physics 2025-10-16 Liyang Hu , Chong Chen

Spectral computed tomography (CT) has recently emerged as an advanced version of medical CT and significantly improves conventional (single-energy) CT. Spectral CT has two main forms: dual-energy computed tomography (DECT) and…

Scatter due to interaction of photons with the imaged object is a fundamental problem in X-ray Computed Tomography (CT). It manifests as various artifacts in the reconstruction, making its abatement or correction critical for image quality.…

Medical Physics · Physics 2024-01-30 Berk Iskender , Yoram Bresler

Multi-source stationary computed tomography (MSS-CT) offers significant advantages in medical and industrial applications due to its gantry-less scan architecture and/or capability of simultaneous multi-source emission. However, the lack of…

Medical Physics · Physics 2025-01-20 Yingxian Xia , Zhiqiang Chen , Li Zhang , Yuxiang Xing , Hewei Gao

The characteristics of an x-ray spectrum can greatly influence imaging and related tasks. In practice, due to the pile-up effect of the detector, it's difficult to directly measure the spectrum of a CT scanner using an energy resolved…

Medical Physics · Physics 2015-03-09 Wei Zhao , Kai Niu , Sebastian Schafer , Kevin Royalty

Scattered coincidences introduce quantitative bias in positron emission tomography (PET) and must be compensated during reconstruction. Conventional scatter estimates typically rely on simplified cylindrical scanner models that omit…