Multi-detector System Research Articles

Calculation of efficiency and resolution of a hexagonal NaI(Tl) detector as a function of source position

Most gamma-ray scintillation detectors currently in use are made from inorganic materials that have a relatively high electron density. Quite often they are used to build multidetector systems that provide high scintillation light output. The performance of a gamma radiation detector (its detection efficiency) depends on the shape and size of the crystal, as well as on the source-to-detector geometry used. The NaI(Tl) gamma detector exhibits moderate energy resolution but relatively high gamma-ray detection efficiency and fast time response. In this work, the efficiency and resolution of a scintillation hexagonal detector are studied to optimize its response function. This type and size of scintillator were selected to construct a budget-friendly, reconfigurable, easy-to-maintain multidetector system for registering gamma-rays following fission, capture, and inelastic neutron scattering reactions, with reasonably good energy and time resolutions The research results made it possible to establish a geometric solid angle that increases the efficiency of recording gamma-ray radiation of the hexagonal NaI(Tl) scintillation probe under study.

Discussion about a new possible experiment for detection of resonance Mössbauer electron neutrinos

Up to date, resonant neutrino emission and absorption, although predicted more than half a century ago, has not been measured. We propose a new neutrino resonance experiment exploiting the isotope 55Fe. Experimental features such as the use of sources, detectors and experimental conditions are discussed in detail. For the resonant neutrino absorption cross-section in the range of 10−38 to 10−37 cm2, resonant Mössbauer neutrinos can be detected using high-activity commercially available radioactive sources in conjunction with a multi-detector system. Although the experiment has the same serious difficulties as other neutrino experiments, it offers unique opportunity in an effort to provide the first successful detection of resonant Mössbauer neutrinos. In the case of no signal, the proposed experiment will provide state-of-the art information and unprecedented limits on the cross-section parameters for resonant neutrino absorption.

Passive single-sphere multi-detector spectrometry system for profiling of neutron fields in the thermal to 20 MeV energy range

This study explores the development and application of a custom-designed single-sphere multi-detector spectrometer (SSMDSS) for characterizing neutron fields. Stray neutrons in reactor and accelerator facilities present complex, energy-diverse fields. Accurately assessing these fields is crucial for personnel safety. The SSMDSS system is designed to address this challenge, offering a compact and passive dosimetry solution for constrained workspaces. We studied the performance of SSMDSS in two environments: radio-nuclide based neutron sources and stray neutron fields at a research reactor hall. Our investigation demonstrates that SSMDSS provide reliable neutron energy distributions. The performance of the SSMDSS was compared with commercially available ROSPEC system. SSMDSS exhibits superior resolution due to its design, leading to a more accurate measurement of low-energy fluence when compared with ROSPEC. This distinction is reflected in various measured parameters, including average energy and fluence-to-dose conversion coefficients. Inside the reactor hall, SSMDSS measured a fluence-to-dose conversion coefficient of 121 pSv.cm2 compared to ROSPEC's 83 pSv.cm2. Additionally, SSMDSS measured a higher average energy (0.25 MeV) compared to ROSPEC (0.14 MeV). While ROSPEC remains a valuable tool for real-time data collection in dynamic fields with high gamma backgrounds, SSMDSS presents itself as a viable alternative for neutron spectrometry in neutron work fields due to its compact design and passive dosimetry capabilities. This makes it particularly suitable for deployment in constrained workspaces with potential stray neutron exposure.

A Rule-Based Automated Chemical Recognition Algorithm for a Multi-Cell Multi-Detector Micro Gas Chromatograph

A chemical recognition algorithm is an integral part of any autonomous microscale gas chromatography (µGC) system for automated chemical analysis. For a multi-detector µGC system, the chemical analysis must account for the retention time of each chemical analyte as well as the relative response of each detector to each analyte, i.e., the detector response pattern (DRP). In contrast to the common approaches of heuristically using principal component analysis and machine learning, this paper reports a rule-based automated chemical recognition algorithm for a multi-cell, multi-detector µGC system, in which the DRP is related to theoretical principles; consequently, this algorithm only requires a small amount of calibration data but not extensive training data. For processing both the retention time and the raw DRP, the algorithm applies rules based on expert knowledge to compare the detected peaks; these rules are located in a customized software library. Additionally, the algorithm provides special handling for chromatogram peaks with a small signal-to-noise ratio. It also provides separate special handling for asymmetrical peaks that may result from surface adsorptive analytes. This work also describes an experimental evaluation in which the algorithm used the relative response of two complementary types of capacitive detectors as well as a photoionization detector that were incorporated into the µGC system of interest. In these tests, which were performed on chromatograms with 21–31 peaks for each detector, the true positive rate was 96.3%, the true negative rate was 94.1%, the false positive rate was 5.9%, and the false negative rate was 3.7%. The results demonstrated that the algorithm can support µGC systems for automated chemical screening and early warning applications.

A novel algorithm for evaluating cement azimuthal density based on perturbation theory in horizontal well

Cement density monitoring plays a vital role in evaluating the quality of cementing projects, which is of great significance to the development of oil and gas. However, the presence of inhomogeneous cement distribution and casing eccentricity in horizontal wells often complicates the accurate evaluation of cement azimuthal density. In this regard, this paper proposes an algorithm to calculate the cement azimuthal density in horizontal wells using a multi-detector gamma-ray detection system. The spatial dynamic response functions are simulated to obtain the influence of cement density on gamma-ray counts by the perturbation theory, and the contribution of cement density in six sectors to the gamma-ray recorded by different detectors is obtained by integrating the spatial dynamic response functions. Combined with the relationship between gamma-ray counts and cement density, a multi-parameter calculation equation system is established, and the regularized Newton iteration method is employed to invert casing eccentricity and cement azimuthal density. This approach ensures the stability of the inversion process while simultaneously achieving an accuracy of 0.05 g/cm3 for the cement azimuthal density. This accuracy level is ten times higher compared to density accuracy calculated using calibration equations. Overall, this algorithm enhances the accuracy of cement azimuthal density evaluation, provides valuable technical support for the monitoring of cement azimuthal density in the oil and gas industry.

Degradation of polysorbate investigated by a high-performance liquid chromatography multi-detector system with charged aerosol and mass detection

Polysorbate 80 is widely used as a formulation component in biopharmaceutical drug products. Recent studies have shown that polysorbate 80 is readily degraded either through direct or indirect means. The degradation of polysorbate 80 causes a concern for the long-term stability of biopharmaceutical drug product, as the breakdown products of polysorbate 80 have been shown to cause adverse effects, such as formation of sub-visible and visible particles and mAb aggregation. Understanding the path and extent of degradation is of a paramount importance for the formulator during formulation development. A multi-detector HPLC system using charged aerosol and mass detection was developed and optimized for the characterization of polysorbate 80 standards. The system included a post-column make-up flow, i.e. an inverse gradient, that enabled constant eluent composition at the detectors. The inverse gradient eliminated the main source of variability for the charged aerosol detector response, thereby enabling the calculation of the mass balance between polysorbate components with different degrees of esterification. Extracted ion chromatograms of the mass detector combined with their respective retention times were used to qualitatively characterize the polysorbate samples down to the individual components. The system was applied to study the degradation of several polysorbate standards which occurred by enzymatic digestion or long-term storage. The system provided detailed information on the mechanism of degradation without the need for additional orthogonal analytical techniques.

A Ray Tracing Model for Electron Optical Imaging in Electron Beam Powder Bed Fusion

The recent success of the process monitoring method Electron Optical Imaging, applied in the additive manufacturing process Electron Beam Powder Bed Fusion, necessitates a clear understanding of the underlying image formation process. Newly developed multi-detector systems enable the reconstruction of the build surface topography in-situ but add complexity to the method. This work presents a physically based raytracing model, which rationalises the effect of detector positioning on image contrast development and masking. The model correctly describes the effect of multiple scattering events on vacuum chamber walls or heat shields and represents, therefore, a predictive tool for designing future detector systems. Most importantly, this work provides a validated method to compute build surface height gradients directly from experimentally recorded electron-optical images of a multi-detector system without any calibration steps. The computed surface height gradients can be used subsequently as input of normal integration algorithms aiming at the in-situ reconstruction of the build surface topography.

Online adaptive radiotherapy and dose delivery accuracy: A retrospective analysis.

With online adaptive radiotherapy (ART), patient-specific quality assurance (PSQA) testing cannot be performed prior to delivery of the adapted treatment plan. Consequently, the dose delivery accuracy of adapted plans (i.e., the ability of the system to interpret and deliver the treatment as planned) are not initially verified. We investigated the variation in dose delivery accuracy of ART on the MRIdian 0.35T MR-linac (Viewray Inc., Oakwood, USA) between initial plans and their respective adapted plans, by analyzing PSQA results. We considered the two main digestive localizations treated with ART (liver and pancreas). A total of 124 PSQA results acquired with the ArcCHECK (Sun Nuclear Corporation, Melbourne, USA) multidetector system were analyzed. PSQA result variations between the initial plans and their respective adapted plans were statistically investigated and compared with the variation in MU number. For the liver, limited deterioration in PSQA results was observed, and was within the limits of clinical tolerance (Initial=98.2%, Adapted=98.2%, p=0.4503). For pancreas plans, only a few significant deteriorations extending beyond the limits of clinical tolerance were observed and were due to specific, complex anatomical configurations (Initial=97.3%, Adapted=96.5%, p=0.0721). In parallel, we observed an influence of the increase in MU number on the PSQA results. We show that the dose delivery accuracy of adapted plans, in terms of PSQA results, is preserved in ART processes on the 0.35T MR-linac. Respecting good practices, and minimizing the increase in MU number can help to preserve the accuracy of delivery of adapted plans as compared to their respective initial plans.

Nash mixed detection strategy of multi-type network attack based on zero-sum stochastic game

The defense strategy of the Internet of Things (IoT) under hacker attack is a crucial issue in the security field of industry. When IoT plants are attacked by hackers, it is impossible to understand the type of attack employed by the hackers. At this point, we need a detection mechanism that can cope with the known multiple types of network attacks. In this paper, we focus on the issue of IoT security defense and construct a multi-detector detection system capable of detecting multiple types of network attacks based on a zero-sum stochastic game framework. The system can choose between multiple detectors according to a mixed Nash equilibrium strategy that takes into account both the detection cost and the detection effect. Finally, we present a simulation comparison between the multi-detector system and the single detector system to verify that the mixed strategy leads to higher detection effectiveness and lower control performance loss.

Three-dimensional Maxillofacial Morphology Measurements in Japanese Adults with Normal Occlusion.

Accurate orthodontic analysis and diagnosis based on anatomical landmarks is essential to the success of orthodontic treatment. Helical computed tomography (CT) has evolved markedly, and dentists can now quickly obtain 3-dimensional (3D) reconstruction data using this imaging modality. The planning of orthodontic treatment had traditionally been based on cephalometric analysis using 2D landmarks. This study aimed to collect 3D morphological data using CT images to establish new landmarks for analysis and diagnosis in orthodontic treatment. Twenty male and 20 female adult Japanese dry skulls with of normal occlusion were selected. The skulls were scanned using a multidetector helical CT system (SIEMENS, Volume Zoom Plus 4, Germany). Models were reconstructed using 3D measurement software (Simplant, Dentsply Sirona, Tokyo, Japan) and 45 landmarks determined. Three-dimensional measurement for a total of 30 items representing these landmarks was then performed. The results provided 3D standard values for maxillofacial morphology in adult Japanese individuals with normal occlusion. These measurement items should allow the disadvantages of 2D cephalometric analysis to be overcome.

Effect of Chest Computed Tomography Kernel Use on Emphysema Score in Severe Chronic Obstructive Pulmonary Disease Patients Evaluated for Lung Volume Reduction

Background: Chest computed tomography (CT) emphysema quantification is a vital diagnostic tool in patient evaluation for bronchoscopic lung volume reduction (BLVR). Smooth kernels for CT image reconstruction are generally recommended for quantitative analyses. This recommendation is not always followed, which may affect quantification of emphysema extent and eventually, treatment decisions. Objective: The main goal is to demonstrate the influence of CT reconstruction kernels on emphysema quantification in patients with severe COPD, considered for BLVR. Methods: Chest CT scans were acquired with one multi-detector CT system and reconstructed using three different kernels: smooth, medium smooth, and sharp. Other parameters were kept constant. Emphysema scores (ESs), meaning the percentage of voxels below −950 Hounsfield units, were calculated and compared to the smooth reference kernel using paired t tests. Bland-Altman plots were made to assess the biases and limits of agreement between kernels. Results: Ninety-eight COPD patient CT scans were analyzed. The sharp kernel had a systematic bias of 6.2% and limits of agreement of 16.6% to −4.2% compared to the smooth kernel. The medium smooth kernel had a systematic bias of 5.7% and limits of agreement of 9.2% and 2.2% compared to the smooth kernel. The ES differed, for a single patient, up to 18% for different kernels. Conclusions: Chest CT kernel reconstruction can lead to a significant difference in emphysema severity quantification. This may cause invalid treatment selection in COPD patients evaluated for BLVR. Standardization of a smooth CT kernel setting and/or normalization to a standard kernel is strongly recommended.

Spectrometry of leakage photoneutrons of 18 MV medical accelerator head by Sohrabi passive multi-directional spherical neutron spectrometry system

PurposeSpectrometry of leakage photoneutrons (PN) of a Siemens ONCOR medical linear accelerator head by applying recently invented Sohrabi passive multi-directional multi-detector neutron spherical spectrometry system; measurements of scientific interest and of importance for meeting the regulatory and safety standards. MethodsThe neutron spectrometry system applied consists of 6 polycarbonate/10B detectors mounted on 6 sides of a polyethylene cube used as bare and also embedded at center of 8 PE spheres of different diameters. Multi-directional and mean PN spectra at isocenter as well as at the left and right sides of head at 100 cm distance from the X-ray target on its plane of 10x10 cm2 18-MV X-ray beams were determined applying Multisphere Neutron Spectrometry Unfolding Code (MNSU + ). ResultsThe well-resolved unfolded directional leakage PN spectra obtained at the 3 positions showed a thermal PN peak of lower intensityfollowed by a tail of epithermal PNs before reaching a fast PN higher peak.“ The mean PN energy are 0.47 ± 0.03 MeV and 0.48 ± 0.02 MeV respectively for the left and right sides of the head and 0.48 ± 0.02 MeV at the isocenter. ConclusionsDue to importance of leakage PN spectra of an accelerator head being of scientific interest and for meeting regulatory and safety standards, well-resolved leakage PN spectra of 3 locations of the medical accelerator head were determined using Sohrabi passive multi-directional neutron spectrometry system. It is a novel learning that the mean PN spectra and mean PN energy of the 3 locations are quite similar within statistical variations.

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

Supramolecular Nanohelix Fabricated by Pillararene-Based Host–Guest System for Chirality Amplification, Transfer, and Circularly Polarized Luminescence in Water

The Performance of EDXS at Elevated Sample Temperatures Using a MEMS-Based In Situ TEM Heating System

Since the development of MEMS heating holders, dynamic in-situ experiments at elevated temperatures may be complemented by X-ray spectrometry for chemical analysis. Although the amount of IR radiation is small when compared to furnace holders, the influence of IR radiation emitted from the heating device on the quality of the X-ray spectra is significant. In this work, we systematically examine the influence of infrared (IR) radiation generated by MEMS-based in situ heating systems (DENSsolutions single- and double-tilt holders) on the results and interpretation of energy-dispersive X-ray (EDX) spectra through simulation and measurement. Focal points of interest in this study are the influence of holder geometry, shadowing and orientation with respect to the different emission characteristics of IR and X-ray photons and their interaction with a side-entry and a multi-detector system. IR photons substantially contribute to count rates, dead time, electronic noise levels, energy resolution, and detection efficiency of semiconductor detectors. At higher sample temperatures, they ultimately limit the feasibility of EDXS for elemental characterization and especially the traceability of low-Z elements. This work provides a quantitative insight into the influence of all relevant parameters related to in situ heating experiments on the spectral quality. Bearing this in mind, we aim to provide a guide to optimizing in situ heating experiments with respect to chemical EDXS analysis.

Radio-Electronic Modules and Radiation Monitoring Systems based on Diamond Detectors

An overview of the current state and promising areas of application of semiconductor diamond detectors for creating radio-electronic monitoring systems for ionizing studies based on them is given. The main attention is paid to the creation of multifunctional space radiation monitoring systems that combine a set of diamond detectors and hardware and software tools that provide diagnostics of dose and spectrometric characteristics of various types of radiation. The data on the developed and manufactured samples of blocks and on-board control systems for cosmic and ionizing radiation are presented. The overview shows that diamond ionizing radiation detectors (IRD) are actively used in the creation of radio-electronic devices and monitoring systems for ionizing and cosmic radiation. The use of diamond IRD in combination with the developed design and technological solutions, hardware and software principles for the construction of such devices make it possible to create samples of on-board onboard avionics for separate measurement of the parameters of cosmic radiation and neutron fluxes, gamma radiation, characterized by small dimensions, high speed, hardness to radiation, mechanical and temperature influences. Multifunctional systems for ionizing radiation detection based on diamond detectors use the accumulated experience of successful development and application of discrete diamond IRD allowed us to start creating multifunctional modules and radiation monitoring systems (RMS) based on them. Theыыыыыы creation of such devices allows us to practically demonstrate the traditional advantages of discrete DIRD (high speed, the highest radiation hardness, high resistance to mechanical and thermal influences) in on-board equipment with smaller mass dimensions. The main structural and technological solutions that ensure the creation and effective functioning of RMS based on diamond IRD are the following: (1) separation the IR flow into energy sub-bands; (2) the use of software and hardware processing of data received from the IRD; (3) using a multi-detector system. Further development of research and development in these areas, in addition to solving the target tasks of radio-electronic instrumentation, will stimulate technological progress in various areas of solid-state electronics, including materials science and physics of wide-band semiconductors, the development of an experimental and technological base for the synthesis of diamond bulk crystals and multilayer structures, the creation of new technologies for ion-plasma processing of semiconductors, and a number of others.

Time domain optical imaging device based on a commercial time-to-digital converter.

Time-domain diffuse optical imaging is a noninvasive technique that uses pulsed near-infrared light as the interrogation source to produce quantitative images displaying the variation in blood volume and oxygenation in the human brain. Measuring the times of flights of photons provides information on the photon pathlengths in tissue, which enables absolute concentrations of the oxygenated and deoxygenated forms of hemoglobin to be estimated. Recent advances in silicon electronics have enabled the development of time-domain systems, which are lightweight and low cost, potentially enabling the imaging technique to be applied to a far greater cohort of subjects in a variety of environments. While such technology usually depends on customized circuits, in this article, we present a system assembled from commercially available components, including a low-cost time-to-digital converter and a silicon photomultiplier detector. The system is able to generate histograms of photon flight times at a rate of 81-90 kS/s and with a sampled bin width of 54ps. The linearity and performance of the system are presented, and its potential as the basis for a modular multi-detector imaging system is explored.

Relative Enhancement Ratio of Portal Venous Phase to Unenhanced CT in the Diagnosis of Lipid-poor Adrenal Adenomas.

Background The development of an accurate, practical, noninvasive, and widely available diagnostic approach to characterize lipid-poor adrenal lesions (greater than 10 HU at unenhanced CT) remains an ongoing demand. Purpose To investigate whether combined assessment of unenhanced and portal venous phase CT allows for the differentiation of lipid-poor adrenal adenomas from nonadenomas. Materials and Methods Patients with lipid-poor adrenal lesions who underwent unenhanced and portal venous phase CT with a single-energy scanner between January 2016 and March 2020 were identified retrospectively. For each lesion, the unenhanced and contrast-enhanced attenuation were measured; the absolute enhancement (contrast-enhanced minus unenhanced attenuation [HU]) and relative enhancement ratio ([absolute enhancement divided by unenhanced attenuation] × 100%) were calculated. The sensitivity achieved at 95% specificity to distinguish adenomas from nonadenomas was determined with receiver operating characteristic curve analysis and compared among parameters with use of the McNemar test. Results A total of 220 patients (mean age ± standard deviation, 66 years ± 12; 134 men) with 131 lipid-poor adenomas and 89 nonadenomas were analyzed. The sensitivity (achieved at 95% specificity) of the relative enhancement ratio (86% [113 of 131 adenomas; 95% CI: 79, 92] at a threshold of >210%) was higher than that of unenhanced attenuation (50% [66 of 131 adenomas; 95% CI: 42, 59] at a threshold of ≤21 HU), contrast-enhanced attenuation (3% [four of 131 adenomas; 95% CI: 1, 8] at a threshold of >120 HU), and absolute enhancement (24% [32 of 131 adenomas; 95% CI: 17, 33] at a threshold of >74 HU; all P < .001). The sensitivities of the relative enhancement ratio were 100% (58 of 58 adenomas; 95% CI: 94, 100), 83% (52 of 63 adenomas; 95% CI: 71, 91), and 30% (three of 10 adenomas; 95% CI: 7, 65) for adenomas measuring unenhanced attenuation of more than 10 HU up to 20 HU, 21-30 HU, and more than 30 HU, respectively. Conclusion A relative enhancement ratio threshold of greater than 210%, measured at unenhanced and portal venous phase CT, accurately differentiated lipid-poor adenomas from nonadenomas, particularly for lesions with unenhanced attenuation of 10-30 HU. © RSNA, 2021 Online supplemental material is available for this article.

Design and development of a plastic scintillator based whole body β/γ contamination monitoring system

Plastic scintillation detectors based whole body β/γ contamination monitors are developed for use in radiation facilities. This microcontroller-based multi-detector system uses 13 plastic scintillator detectors, with minimized dead detection zones, monitoring the whole body, and conforming to the contamination limit prescribed by the regulatory authority. This system has the features for monitoring hands, feet, head, and face β/γ using contamination monitors and portal exit monitors. It can detect gamma sources at a dose rate of 10 nGyh−1. The system is calibrated using β sources 90Sr/90Y, 204Tl, and 36Cl, and the efficiency is found to be 29%, 22%, and 18%, respectively. The minimum detectable β/γ contamination is 0.15 Bqcm−2, which is significantly less than the minimum detection objectives on head, face, hands, and feet.

SOFTWARE AT MOBILE SPECTROMETER WITH CZT-DETECTOR

The technology is based on a semiconductor CdZnTe-portable (almost the size of a mobile phone) gamma-ray spectrometer with high resolution, which provides high efficiency of rapid identification of radionuclides and assessment of radiation dose from low to moderately high levels. The CdZnTe gamma-ray spectrometer is a highly efficient device based on the use of CdZnTe(CZT) semiconductor detectors operating at room temperature with very low power consumption, a digital multichannel analyzer, and amicrocomputer. CdZnTe-portable spectrometer is a self-contained device and consists of three modules -a detector module, a multichannel analyzer, and a microcomputer. The detector module contains a high-quality CdZnTe detector, a preamplifier, and a high voltage power supply for the detector. There are detector modules with different volumes of the CZT detector from 5mm3to 1600mm3. It is possible to use a multi-detector system. The analyzer module contains an amplifier, a digital signal processor, a low voltage power supply, and a computer interface. The microcomputer software interacts with the multichannel analyzer, analyzes gamma spectra, and provides the accumulation of time profiles of the dose of gamma radiation, communication with other information systems. Spectrometric measurements in real-time make it possible to use "electronic collimation" technologies to build a map of the radiation field and localize sources of ionizing radiation, with the subsequent certification of identified sources, creation of an effective radiation monitoring system with the functions of certification of ionizing sources radiation. The corresponding software allows you to solve the following tasks –building a three-dimensional map of the fields of ionizing radiation of various degrees of spatial detailing, taking into account the radiation energy, localization, and certification of gamma radiation sources. The special laboratory kit is based on μSPEC microspectrometers. A LattePanda single board computeris used to control the operation of spectrometers, collect and analyze data. LattePanda –A Windows10 Computer with integrated Arduino. This explains the choice of LattePanda. Windows10 applicationallows you to use the WinSPEC software to control the multichannel analyzer operation supplied with the spectrometer. The built-in Arduino allows you to remote control the movement of the radiation source during laboratory experiment. Both the traditionalproblems of calibrating spectrometers (energy calibration and efficiency curves), including those for various source geometries, processing the measured spectra using standard programs, calculating the activity of sources, and the problem of creating a spectra processing program and a spectrometer control program are considered. The values of the minimum detectable activity are given.

Improvement in sampling and modulation of multiplexing with temporal shuttering of adaptable apertures in a brain-dedicated multi-pinhole SPECT system

We are developing a multi-detector pinhole-based stationary brain-dedicated SPECT system: AdaptiSPECT-C. In this work, we introduced a new design prototype with multiple adaptable pinhole apertures for each detector to modulate the multiplexing by employing temporal shuttering of apertures. Temporal shuttering of apertures over the scan time provides the AdaptiSPECT-C with the capability of multiple-frame acquisition. We investigated, through analytic simulation, the impact of projection multiplexing on image quality using several digital phantoms and a customized anthropomorphic phantom emulating brain perfusion clinical distribution. The 105 pinholes in the collimator of the system were categorized into central, axial, and lateral apertures. We generated, through simulation, collimators of different multiplexing levels. Several data acquisition schemes were also created by changing the imaging time share of the acquisition frames. Sensitivity increased by 35% compared to the single-pinhole-per-detector base configuration of the AdaptiSPECT-C when using the central, axial, and lateral apertures with equal acquisition time shares within a triple-frame scheme with a high multiplexing scenario. Axial and angular sampling of the base configuration was enhanced by adding the axial and lateral apertures. We showed that the temporal shuttering of apertures can be exploited, trading the sensitivity, to modulate the multiplexing and to acquire a set of non-multiplexed non-truncated projections. Our results suggested that reconstruction benefited from utilizing both non-multiplexed projections and projections with modulated multiplexing resulting in a noticeably reduction in the multiplexing-induced image artefacts. Contrast recovery factor improved by 20% (9%) compared to the base configuration for a Defrise (hot-rod) phantom study when the central and axial (lateral) apertures with equal time shares were combined. The results revealed that, as an overall trend at each simulated multiplexing level, lowest normalized root-mean-square errors for the brain gray-matter regions were achieved with the combined usage of the central apertures and axial/lateral apertures.