Today, PET and SPECT tracers cannot be imaged simultaneously at high resolutions but require 2 separate imaging systems. This paper introduces a Versatile Emission Computed Tomography system (VECTor) for radionuclides that enables simultaneous submillimeter of single-photon positron-emitting radiolabeled molecules. <b>Methods:</b> γ-photons produced both by electron–positron annihilation emitters are projected onto the same detectors means novel cylindric high-energy collimator containing...

Presently used clinical brain SPECT suffers from limited spatio-temporal resolution. Here we investigate the feasibility of high-resolution and high-sensitivity full-ring multi-pinhole (MP-SPECT). Using an analytical model optimized pinhole-detector geometries MP-SPECT for different detector intrinsic resolutions Ri. System resolution sensitivity were compared to conventional SPECT. The comparison system systems was done at matched sensitivity, which achieved by tuning pinhole diameters....

SPECT with submegabecquerel amounts of tracer or subsecond time resolution would enable a wide range new imaging protocols such as screening tracers initially low yield labeling efficiency, receptor densities, even performing outside regular radiation laboratories. To this end we developed dedicated ultra-high-sensitivity pinhole SPECT. <b>Methods:</b> A cylindric collimator 54 focused 2.0-mm-diameter conical pinholes was manufactured and mounted in stationary small-animal system. The system...

PET imaging of rodents is increasingly used in preclinical research, but its utility limited by spatial resolution and signal-to-noise ratio the images. A recently developed system uses a clustered-pinhole collimator, enabling high-resolution, simultaneous SPECT tracers. Pinhole collimation strongly departs from traditional electronic achieved via coincidence detection PET. We investigated potential such design direct comparison to scanner. <b>Methods:</b> Two small-animal scanners, 1 with...

Small-animal SPECT systems with stationary detectors and focusing multiple pinholes can achieve excellent resolution-sensitivity trade-offs. These are able to perform fast total-body scans by shifting the animal bed through collimator using an automated xyz stage. However, so far, a large number of highly overlapping central fields view have been used, at cost overhead time needed for repositioning long image reconstruction times due high numbers projection views.To improve temporal...

Ordered subsets expectation maximization (OS-EM) is widely used to accelerate image reconstruction in single photon emission computed tomography (SPECT). Speedup of OS-EM over maximum likelihood (ML-EM) close the number used. Although a high can shorten times significantly, it also cause severe artifacts such as improper erasure reconstructed activity if projections contain few counts. We recently showed that be prevented by using count-regulated (CR-OS-EM) algorithm which automatically...

Abstract Objective. Utilizing prompt gammas in preclinical pinhole-collimated PET avoids image degradation due to positron range blurring and photon down scatter, enables multi-isotope can improve counting statistics for low-abundance emitters. This was earlier reported 124I, 89Zr simultaneous 124I -18F using the VECTor scanner (MILabs, The Netherlands), demonstrating sub-mm resolution despite long ranges. aim of present study is investigate if such imaging also feasible a large variety...

We study the asymptotic dynamics of a driven quantum two-level system coupled via detector to environment. find multiphoton resonances which are due entanglement qubit and detector. Different regimes studied by employing perturbative Floquet-Born-Markov approach for $\mathrm{\text{qubit}}+\mathrm{\text{detector}}$ system, as well nonperturbative real-time path integral schemes spin-boson system. analytical results resonances, including red blue sidebands. They agree with those exact ab...

State-of-the-art small-animal single photon emission computed tomography (SPECT) enables sub-half-mm resolution imaging of radio-labelled molecules. Due to severe penetration through pinhole edges, current multi-pinhole SPECT is not suitable for high-resolution photons with high energies, such as the annihilation emitted by positron emitting tracers (511 keV). To deal this edge penetration, we introduce here clustered (CMP): each in a cluster has narrow opening angle reduce penetration....

The combined α-, γ-, and x-ray emitter ²¹³Bi (half-life, 46 min) is promising for radionuclide therapy. SPECT imaging of challenging, because most emitted photons have a much higher energy (440 keV) than common in SPECT. We assessed capabilities the Versatile Emission Computed Tomograph (VECTor) dedicated to (simultaneous) preclinical both PET isotopes over wide photon range 25–600 keV. <b>Methods:</b> VECTor was equipped with clustered pinhole collimator. Both 79 keV x-rays 440...

Direct conversion photon counting detectors (PCDs) using CdTe, CZT, or Si for the sensor material are being investigated and manufactured. Indirect conversion, scintillator-based PCDs have historically thought to be too slow high flux requirements of diagnostic CT. Recent scintillators e.g. PET applications very fast inspire us rethink this paradigm. We evaluate potential a LaBr3:Ce PCD Monte Carlo simulations. compared CdTe PCD, assuming pixel density 9 pixels/mm2 in each case surrounding...

Shot noise in a chaotic cavity (Lyapunov exponent $\lambda$, level spacing $\delta$, linear dimension $L$), coupled by two $N$-mode point contacts to electron reservoirs, is studied as measure of the crossover from stochastic quantum transport deterministic classical transport. The transition proceeds through formation {\em fully} transmitted or reflected scattering states, which we construct explicitly. fully states contribute mean current $\bar{I}$, but not shot-noise power $S$. We find...

Planar molecular breast imaging (MBI) is rapidly gaining in popularity diagnostic oncology. To add 3D capabilities, we introduce a novel tomosynthesis (MBT) scanner concept based on multi-pinhole collimation. In our design, the patient lies prone with pendant lightly compressed between transparent plates. Integrated webcams view through these plates and allow operator to designate scan volume (e.g. whole or suspected region). The then scanned by translating focusing NaI(Tl) gamma detectors...

SPECT can be used to image dopamine transporter (DaT) availability in the human striatum, e.g. for diagnosis of Parkinson's disease (PD). As traditional provides limited resolution and sensitivity, we proposed a full ring focusing multi-pinhole system (G-SPECT-I (Beekman 2015 Eur. J. Nucl. Med. Mol. Imaging 42 S209)) which demonstrated 2.5 mm reconstructed phantom scans. G-SPECT-I achieves data completeness scan region interest by translating patient bed with an xyz-stage combining...

Despite improvements in small animal PET instruments, many tracers cannot be imaged at sufficiently high resolutions due to positron range, while multi-tracer is hampered by the fact that all annihilation photons have equal energies. Here we realize multi-isotope and sub-mm resolution of isotopes with several mm range utilizing prompt gamma are commonly neglected. A PET-SPECT-CT scanner (VECTor/CT, MILabs, The Netherlands) equipped a high-energy cluster-pinhole collimator was used image 124I...

We consider two quantum coherent conductors interacting weakly via long range Coulomb forces. describe the interaction in terms of two-particle collisions described by a scattering matrix. As an example we determine transmission probability and correlations experiment find that results can be expressed density-of-states matrices noninteracting scatterers.

Gamma cameras based on charge-coupled devices (CCDs) and micro-columnar CsI scintillators can reach high spatial resolutions. However, the gamma interaction probability of these is low (typically <30% at 141 keV) due to limited thickness presently available scintillators. Continuous improve but suffer from increased light spread compared columnar In addition, for both types scintillators, photons incident an oblique angle reduce resolution variable depth (DOI). To spectral characteristics...

Pinhole SPECT often provides an excellent resolution sensitivity trade-off for radionuclide imaging compared to with parallel holes, particularly when small experimental animals like rodents. High absorption pinhole materials are chosen because of their low edge penetration and therefore good system resolution. Capturing more photons in the edges however results decreased if diameter remains same, which may partly undo beneficial effect on In search optimal we have projection data...

In clinical brain SPECT, correction for photon attenuation in the patient is essential to obtain images which provide quantitative information on regional activity concentration per unit volume (kBq.[Formula: see text]). This generally requires an map ([Formula: text] map) denoting coefficient at each voxel often derived from a CT or MRI scan. However, such additional scan not always available and method may suffer registration errors. Therefore, we propose SPECT-only-based strategy...

Abstract Background Gamma camera imaging, including single photon emission computed tomography (SPECT), is crucial for research, diagnostics, and radionuclide therapy. cameras are predominantly based on arrays of multipliers tubes (PMTs) that read out NaI(Tl) scintillation crystals. In this way, standard gamma can localize ɣ‐rays with energies typically ranging from 30 to 360 keV. the last decade, there has been an increasing interest towards imaging outside conventional clinical energy...

We identify the time T between Andreev reflections as a classical adiabatic invariant in ballistic chaotic cavity (Lyapunov exponent lambda), coupled to superconductor by an N-mode constriction. Quantization of adiabatically torus phase space gives discrete set periods T(n), which turn generate ladder excited states epsilon (nm)=(m+1/2)pi(h) /T(n). The largest quantized period is Ehrenfest T(0)=lambda(-1)ln(N). Projection onto coordinate plane shows that wave functions inside are squeezed...

The recently developed Versatile Emission Computed Tomography (VECTor) technology enables high-energy SPECT and simultaneous PET of small animals at sub-mm resolutions.VECTor uses dedicated clustered pinhole collimators mounted in a scanner with three stationary large-area NaI(Tl) gamma detectors.Here, we develop validate image reconstruction methods that compensate for degradation by incorporating accurate models the transport annihilation photons.Ray tracing software was used to calculate...

We study a realistic model for driven qubits using the numerical solution of Bloch-Redfield equation as well analytical approximations high-frequency scheme. Unlike in idealized rotating-wave models suitable NMR or quantum optics, we driving term which neither is orthogonal to static nor leaves adiabatic energy value constant. investigate underlying dynamics and analyze spectroscopy peaks obtained recent experiments. show, that unlike case, this system exhibits nonlinear effects. width how...