Abstract Background Positron emission tomography (PET) has had a transformative impact on oncological and neurological applications. However, still much of PET's potential remains untapped with limitations primarily driven by low spatial resolution, which severely hampers accurate quantitative PET imaging via the partial volume effect (PVE). Purpose We present experimental results practical cost‐effective ultra‐high resolution brain‐dedicated scanner, using our depth‐encoding Prism‐PET...

The structure of amorphous selenium is clouded with much uncertainty and contradictory results regarding the dominance polymeric chains versus monomer rings. analysis diffraction radial distribution functions are inconclusive because similarities between crystalline allotropes in terms coordination number, bond length, angle, dihedral angle. Here, we took a different approach probed molecular symmetry thermodynamically unstable state via structural phase transformations. We verified...

Depth-encoding detectors with single-ended readout provide a practical, cost-effective approach for constructing high-resolution and high-sensitivity PET scanners. However, the current iteration of such uses uniform glass light-guide to achieve depth encoding, resulting in nonuniform performance throughout detector array due suboptimal intercrystal light sharing. We introduce Prism-PET, single-ended-readout module segmented composed an prismatoids that enhanced, deterministic <b>Methods:</b>...

Active matrix flat panel imagers (AMFPI) have limited performance in low dose applications due to the electronic noise of thin film transistor (TFT) array. A uniform layer avalanche amorphous selenium (a-Se) called high gain rushing photoconductor (HARP) allows for signal amplification prior readout from TFT array, largely eliminating effects noise. The authors report preliminary measurements first HARP structure developed direct deposition onto a array.The is fabricated on glass substrate...

Quantitative in vivo molecular imaging of fine brain structures requires high-spatial resolution and high-sensitivity. Positron emission tomography (PET) is an attractive candidate to introduce into standard clinical care due its highly targeted versatile capabilities based on the radiotracer being used. However, PET suffers from relatively poor spatial compared other modalities, which limits ability accurately quantify uptake regions nuclei smaller than 3 mm diameter. Here we a new...

Abstract Objective. Inter-crystal scattering (ICS) in light-sharing positron emission tomography (PET) detectors leads to ambiguity positioning the initial interaction, which significantly degrades contrast, quantitative accuracy, and spatial resolution of resulting image. Here, we attempt resolve ICS a depth-encoding detector by exploiting confined, deterministic enabled segmented light guide unique Prism-PET. Approach. We first considered test case between two adjacent crystals using an...

Abstract Background High‐resolution brain positron emission tomography (PET) scanner is emerging as a significant and transformative non‐invasive neuroimaging tool to advance neuroscience research well improve diagnosis treatment in neurology psychiatry. Time‐of‐flight (TOF) depth‐of‐interaction (DOI) information provide markedly higher PET imaging performance by increasing image signal‐to‐noise ratio mitigating spatial resolution degradation due parallax error, respectively. detector...

Spatial resolution in positron emission tomography using traditional pixelated block detectors is inherently limited by the size of detector array elements, namely, scintillator crystals and readout pixels. Conventional centroiding algorithms based on Anger logic are widely used to localize individual events down level. However, these associated with well-known performance degradation along edges corners arrays. In this article, we explore use convolutional neural networks (CNNs) for 3D...

Depth of interaction (DOI) readout in PET imaging has been researched efforts to mitigate parallax error, which would enable the development small diameter, high-resolution scanners. However, DOI not yet commercialized due lack practical, cost-effective, and data efficient methods. The rationale for this study was develop a supervised machine learning algorithm estimation that can be trained deployed on unique sets crystals.

Depth-of-interaction (DOI) positron emission tomography (PET) detector with time-of-flight (TOF) readout has been developed in recent years. With DOI, PET scanner could achieve high spatial resolution and sensitivity simultaneously. improved TOF readout, better coincidence time (CTR) is achieved, making the localization of events along lines response (LORs) more accurate enhancing reconstructed image quality. Prism-PET a novel DOI-TOF module single-ended readout. It utilizes segmented...

We propose a true solid-state alternative to the vacuum photomultiplier tube using amorphous selenium (a-Se) as bulk avalanche i-layer. A-Se is unique photosensing material in which carrier transport can be shifted entirely from localized extended states where only holes get hot and undergo impact ionization, resulting deterministic non-Markovian gain. To achieve reliable repeatable ionization gain without irreversible breakdown, non-insulating metal oxide n-type...

The use of high resistivity amorphous solids as photodetectors, especially selenium, is currently great interest because they are readily produced over large area at substantially lower cost compared to grown crystalline solids. However, have been ruled out viable radiation detection media for frame-rate applications, such single-photon-counting imaging, low carrier mobilities, transit-time-limited photoresponse, and consequently, poor time resolution. To circumvent the problem charge...

Coincidence time resolution (CTR) in modern time-of-flight (TOF) PET scanners is limited by properties of the detector system, namely scintillator size and material, as well single-photon (SPTR) photon detection efficiency readout pixels. Recent studies have demonstrated effectiveness incorporating depth interaction (DOI) information into TOF to improve CTR. Having multiple timestamps per event has also been shown CTR through leading edge slope estimation. We propose using convolutional...

Amorphous selenium is emerging as a viable large-area imaging detector with avalanche multiplication gain for low-light and low-dose radiation detection applications. A key feature of its process that only holes become “hot” carriers undergo impact ionization. Thus, understanding the transport non-equilibrium hot in extended states pivotal to all device One interesting aspects elemental similar general electronic structure various phase modifications. This stems from strikingly short-range...

Abstract Background Given the large number of readout pixels in clinical positron emission tomography (PET) scanners, signal multiplexing is an indispensable feature to reduce scanner complexity, power consumption, heat output, and cost. Purpose In this paper, we introduce interleaved (iMux) scheme that utilizes characteristic light‐sharing pattern depth‐encoding Prism‐PET detector modules with single‐ended readout. Methods iMux readout, four anodes from every other silicon photomultiplier...

Signal multiplexing is necessary to reduce the large number of readout channels in positron emission tomography (PET) scanners minimize cost and achieve lower power consumption. However, conventional weighted average energy method cannot localize multiplexed events, more sophisticated approaches are for accurate demultiplexing. The purpose this article propose a nonparametric decision tree model demultiplexing signals prismatoid PET (Prism-PET) detector module that consisted <inline-formula...

Memory effects in direct detection solid-state photoconductors are attributed to interrupted charge transport by traps the bulk and result persistent photocurrent lag ghosting. The identified sources for image following cessation of x-ray exposure inhomogeneous electric field’s spatial distribution detrapping space charge. This work shows that latter is dominant mechanism stabilized n-i-p amorphous selenium proposes unipolar charge-sensing detector design reducing improving temporal...

Ultrafast photodetection has traditionally been performed with crystalline photodetectors, which tend to suffer from low production yield, suboptimal detection efficiency, and operational limitations that restrict their potential applications. Amorphous selenium is a unique, disordered photosensing material in carrier transport can be shifted entirely localized extended states where holes get hot, resulting deterministic, non-Markovian impact ionization avalanche, causing exhibit...

Abstract Recent progress in the field of micron-scale spatial resolution direct conversion X-ray detectors for high-energy synchrotron light sources serve applications ranging from nondestructive and noninvasive microscopy techniques which provide insight into structure morphology crystals, to medical diagnostic measurement devices. Amorphous selenium ( a -Se) as wide-bandgap thermally evaporated photoconductor exhibits ultra-low thermal generation rates dark carriers has been extensively...

PurposeActive matrix flat panel imagers (AMFPIs) with thin-film transistor arrays experience image quality degradation by electronic noise in low-dose radiography and fluoroscopy. One potential solution is to overcome using avalanche gain an amorphous selenium (a-Se) (HARP) photoconductor indirect AMFPI. In this work, we aim improve temporal performance of HARP a novel composite hole blocking layer (HBL) structure increase optical quantum efficiency (OQE) CsI:Tl scintillators tellurium (Te)...

Abstract Colloidal quantum dot (CQD) based infrared (IR) photodetectors offer facile wavelength tunability in the IR and low‐cost fabrication. However, owing to their large surface areas, CQDs intrinsically have significant traps critically affecting speed of CQD photodetectors, typically mediated through tedious passivation efforts. In this report, an alternative strategy involving coupling near‐IR photoactive lead sulfide with a thermally evaporated amorphous selenium (a‐Se) hole transport...