We proposed and tested a novel geometry for PET system design analogous to pinhole SPECT called the virtual-pinhole (VP-PET) determine whether it could provide high-resolution images. <b>Methods:</b> analyzed effects of photon acolinearity detector sizes on resolution extended empiric formula reconstructed image conventional earlier predict resolutions VP-PET. To measure VP-PET, we recorded coincidence events as ²²Na point source was stepped across line response between 2...

Statistical image reconstruction algorithms in X-ray computed tomography (CT) provide improved quality for reduced dose levels but require substantial computation time. Iterative that converge few iterations and are amenable to massive parallelization favorable multiprocessor implementations. The separable quadratic surrogate (SQS) algorithm is desirable as it simple updates all voxels simultaneously. However, the standard SQS requires many converge. This paper proposes an extension of leads...

A full-ring PET insert device should be able to enhance the image resolution of existing small-animal scanners. <b>Methods:</b> The consists 18 high-resolution detectors in a cylindric enclosure. Each detector contains cerium-doped lutetium oxyorthosilicate array (12 × 12 crystals, 0.72 1.51 3.75 mm each) coupled position-sensitive photomultiplier tube via an optical fiber bundle made 8 16 square multiclad fibers. Signals from are connected scanner through electronics disabled first ring...

An increasing number of X-ray CT procedures are being conducted with drastically reduced dosage, due at least in part to advances statistical reconstruction methods that can deal more effectively noise than traditional techniques. As data become photon-limited, detailed models necessary count rates drop the levels system electronic noise. We present two options for sinogram pre-treatment improve performance photon-starved measurements, intent following model-based image reconstruction. Both...

We developed a prototype system to evaluate the feasibility of using PET insert device achieve higher resolution from general-purpose animal scanner. <b>Methods:</b> The consists high-resolution detector, computer-controlled rotation stage, and custom mounting plate. detector cerium-doped lutetium oxyorthosilicate array (12 × 12 crystals, 0.8 1.66 3.75 mm³ each) directly coupled position-sensitive photomultiplier tube (PS-PMT). signals were fed into scanner electronics establish...

Markov random fields (MRFs) have been widely used as prior models in various inverse problems such tomographic reconstruction. While MRFs provide a simple and often effective way to model the spatial dependencies images, they suffer from fact that parameter estimation is difficult. In practice, this means typically very structure cannot completely capture subtle characteristics of complex images. paper, we present novel Gaussian mixture field (GM-MRF) can be expressive for denoising The...

A sequential PET/MR system like Philips Gemini TF generates attenuation correction map from an MR image instead of a CT or transmission for PET reconstruction. One problem in MR-based is that the table and coils are invisible images but they may contain high density materials which have to be compensated attenuation. This work investigates impacts several clinical correction. To tables coils, template inserting based approach proposed. Templates generated scans pre-install on system. For...

We are developing novel insert devices for existing whole body PET scanners to achieve better resolution in selected regions of interest such as the head, neck, breast or abdomen. The considered here is a full ring high detectors, which can be placed around object interest. Adding inside scanner leads three different types coincidences: insert–insert, insert–scanner and scanner–scanner. insert–insert scanner–scanner coincidences similar obtained traditional system. have an inherent fan-beam...

Non-linear iterative reconstruction (IR) algorithms have shown promising improvements in image quality at reduced dose levels. However, IR images sometimes may be perceived as having different noise texture than traditional filtered back projection (FBP) reconstruction. Standard linear-systems-based evaluation metrics are limited characterizing such textural differences and non-linear image-quality vs. trade-off behavior, hence predicting potential impact of diagnostic task. In an attempt to...

The presence of metal-artifacts in CT imaging can obscure relevant anatomy and interfere with disease diagnosis. cause occurrence are primarily due to beam hardening, scatter, partial volume photon starvation; however, the contribution artifacts from each them depends on type hardware. A comparison images obtained different metallic hardware various applications, along acquisition reconstruction parameters, helps understand methods for reducing or overcoming such artifacts. In this work, a...

When it comes to extending the lifespan of Wireless Sensor Networks, concept clustering is quite useful because lowers energy consumption required for their operation as well message overhead, network lifetime. sensor networks have unique routing protocol requirements dispersed and architecture. In this paper, a decentralised hierarchical cluster-based WSN algorithm discussed. This method reduces amount control packets by running multi hop algorithms simultaneously. The findings study, when...

In this paper, an attempt has been made to increase the transmission efficiency and network lifetime of a wireless sensor (WSN) by clustering method using Fuzzy logic. Here, cluster head (CH) is elected based on Enhancement for nodes operating in WSN important issue that needs be resolved increasing system performance. The technique found large number benefits with respect achieving least energy consumption. protocols employed intelligent should favor maximum provide from utilized algorithm...

We have developed a PET insert system that can be integrated into clinical PET-CT scanner to improve its image resolution when imaging patient for head and neck cancer. The consists of 28 detector modules arranged two half rings (24.6 cm in diameter). Each an array 13×13 LSO crystals each measuring 2 × 5 mm3, 2.8 mm thick light-guide, R8900-M16 PMT (Hamamatsu, Japan). 16 anode outputs are multiplexed produce 4 position-encoded signals resemble the output typical block scanner. An active...

With the advent of iterative reconstruction algorithms for CT, there is a significant need to develop analysis tools characterize behaviour such algorithms. The mean and variance are standard measures capture first order second moment CT images. However they fail complete images when noise correlated. in projection data may be very well approximated independant uncorrelated, however process introduces correlation Auto-correlation good measure moments an image presence correlated noise. In...

Reduction of CT radiation dose is important due to the potential effects on patients. But lowering incurs degradation in reconstructed image quality, furthering compromise diagnostic and image-based analyses performance. Considering patient health risks, high quality reference images cannot be easily obtained, making assessment challenging. Therefore, automatic no-reference desirable. Leveraging an innovative self-supervised regularization a convolutional neural network, we propose novel,...

We have developed a new type of PET insert system that, when integrated into whole-body scanner, offers the possibility imaging breast and chest wall region with higher resolution sensitivity than scanner alone. The focus this paper is to describe model that can be used within fully 3D iterative reconstruction algorithm accurately measured data. modeled most important components matrix, including spatially-variant geometric factor, inter-crystal penetration, body attenuation. Due irregular...

Abstract Background Photon counting detectors (PCDs) provide higher spatial resolution, improved contrast‐to‐noise ratio (CNR), and energy discriminating capabilities. However, the greatly increased amount of projection data in photon computed tomography (PCCT) systems becomes challenging to transmit through slip ring, process, store. Purpose This study proposes evaluates an empirical optimization algorithm obtain optimal weights for bin compression. is universally applicable spectral...

Photon counting x-ray detectors enable spectral imaging, which can be utilized for material decomposition and quantitative imaging tasks. This study investigates potential benefits of tube voltage optimization, including fast kV switching, on noise. In simulation studies, single scans 80/100/120/140 were tested as well an 80/140 switching pair. Fluences spectra normalized with respect to CTDI keep dose neutral. An open-source response model a realistic Si detector was used in the Cramér–Rao...

Photon counting detectors (PCDs) with energy discrimination capabilities provide spectral information through binning and higher spatial resolution than conventional integrating (EIDs). However, the projection data transmission from detector across slip ring to processing computer becomes more challenging due increased amount of data, including multiple (e.g., 8) bins. In this work, we propose a projection-domain bin weighting method that produces two energy-weighted measurements comparable...