Beam Tomography Research Articles

Development and characterization of a large thermal neutron beam for neutron radiography at Isfahan MNSR

The feasibility study of performing neutron radiography (NR) at the Isfahan Miniature Neutron Source Reactor (MNSR) was carried out in the previous work that was including calculations and experiments in support of the implementation of a prototype NR beam tube. Results were shown the obtained neutron beam from that prototype beam tube had appropriate conditions for NR and it is possible to obtain a large NR beam at this low power research reactor. The main disadvantage of the prototype beam tube was the small size of the beam port with diameter of 5 cm. In this study, a large diameter beam tube is designed and installed at the reactor. This beam tube has a telescopic divergent shape and is installed in the west side of the reactor pool. The neutron beam parameters and image quality of the obtained beam from this beam tube are measured based on ASTM-E545. Results showed that this neutron beam has good quality for NR experiments over a beam diameter of about 25 cm. Also, a simple and practical system, for fill and drain water to the beam tube, is designed and incorporated as a beam shutter in order to maintain the radiation safety.

Brain image quality according to beam collimation width and image reconstruction algorithm: A phantom study

PurposeTo compare quantitatively and qualitatively brain image quality acquired in helical and axial modes on two wide collimation CT systems according to the dose level and algorithm used. MethodsAcquisitions were performed on an image quality and an anthropomorphic phantoms at three dose levels (CTDIvol: 45/35/25 mGy) on two wide collimation CT systems (GE Healthcare and Canon Medical Systems) in axial and helical modes. Raw data were reconstructed using iterative reconstruction (IR) and deep-learning image reconstruction (DLR) algorithms. The noise power spectrum (NPS) was computed on both phantoms and the task-based transfer function (TTF) on the image quality phantom. The subjective quality of images from an anthropomorphic brain phantom was evaluated by two radiologists including overall image quality. ResultsFor the GE system, noise magnitude and noise texture (average NPS spatial frequency) were lower with DLR than with IR. For the Canon system, noise magnitude values were lower with DLR than with IR for similar noise texture but the opposite was true for spatial resolution. For both CT systems, noise magnitude was lower with the axial mode than with the helical mode for similar noise texture and spatial resolution. Radiologists rated the overall quality of all brain images as “satisfactory for clinical use”, whatever the dose level, algorithm or acquisition mode. ConclusionsUsing 16-cm axial acquisition reduces image noise without changing the spatial resolution and image texture compared to helical acquisitions. Axial acquisition can be used in clinical routine for brain CT examinations with an explored length of less than 16 cm.

Novel Design and Application of High-NA Fiber Imaging Bundles for In Vivo Brain Imaging with Two-Photon Scanning Fluorescence Microscopy.

Here, we provide experimental verification supporting the use of short-section imaging bundles for two-photon microscopy imaging of the mouse brain. The 8 mm long bundle is made of a pair of heavy-metal oxide glasses with a refractive index contrast of 0.38 to ensure a high numerical aperture NA = 1.15. The bundle is composed of 825 multimode cores, ordered in a hexagonal lattice with a pixel size of 14 μm and a total diameter of 914 μm. We demonstrate successful imaging through custom-made bundles with 14 μm resolution. As the input, we used a 910 nm Ti-sapphire laser with 140 fs pulse and a peak power of 9 × 104 W. The excitation beam and fluorescent image were transferred through the fiber imaging bundle. As test samples, we used 1 μm green fluorescent latex beads, ex vivo hippocampal neurons expressing green fluorescent protein and cortical neurons in vivo expressing the fluorescent reporter GCaMP6s or immediate early gene Fos fluorescent reporter. This system can be used for minimal-invasive in vivo imaging of the cerebral cortex, hippocampus, or deep brain areas as a part of a tabletop system or an implantable setup. It is a low-cost solution, easy to integrate and operate for high-throughput experiments.

Upgrade of Thomson Scattering Diagnostic on HL-2A

The Thomson scattering diagnostic of the HL-2A tokamak device was upgraded to improve its multi-point diagnostic capability, including new collection optics, fibers bundles, and data analysis code. The small old collection lens was replaced by a six-piece lens with a Cooke optical design. The aperture of its first standard sphere face is 310.125 mm, which successfully increases the amount of collected scattering light by about three times. The new collection optic module allows for up to twenty-six spatial points. A kind of Y-type fiber bundle has also been used to ensure that the fiber end-face matches the image of the laser beam exactly. Additionally, the new data analysis code can provide preview results in seconds. Finally, the multi-point Te diagnostic ability has been significantly improved.

Dynamic CD8+ T cell responses to cancer immunotherapy in human regional lymph nodes are disrupted in metastatic lymph nodes

CD8+ Tcell responses are critical for anti-tumor immunity. While extensively profiled in the tumor microenvironment, recent studies in mice identified responses in lymph nodes (LNs) as essential; however, the role of LNs in human cancer patients remains unknown. We examined CD8+ Tcells in human head and neck squamous cell carcinomas, regional LNs, and blood using mass cytometry, single-cell genomics, and multiplexed ion beam imaging. We identified progenitor exhausted CD8+ Tcells (Tpex) that were abundant in uninvolved LN and clonally related to terminally exhausted cells in the tumor. After anti-PD-L1 immunotherapy, Tpex in uninvolved LNs reduced in frequency but localized near dendritic cells and proliferating intermediate-exhausted CD8+ Tcells (Tex-int), consistent with activation and differentiation. LN responses coincided with increased circulating Tex-int. In metastatic LNs, these response hallmarks were impaired, with immunosuppressive cellular niches. Our results identify important roles for LNs in anti-tumor immune responses in humans.

Accelerated Short Circuiting in Anode‐Free Solid‐State Batteries Driven by Local Lithium Depletion

Abstract“Anode‐free” solid‐state batteries (SSBs), which have no anode active material, can exhibit extremely high energy density (≈1500 Wh L−1). However, there is a lack of understanding of the lithium plating/stripping mechanisms at initially lithium‐free solid‐state electrolyte (SSE) interfaces because excess lithium metal is often used. Here, it is demonstrated that commercially relevant quantities of lithium (>5 mAh cm−2) can be reliably plated at moderate current densities (1 mA cm−2) using the sulfide SSE Li6PS5Cl. Investigations of lithium plating/stripping mechanisms, in conjunction with cryo‐focused ion beam (FIB) imaging, synchrotron tomography, and phase‐field modeling, reveal that the cycling stability of these cells is fundamentally limited by the nonuniform presence of lithium during stripping. Local lithium depletion causes isolated lithium regions toward the end of stripping, decreasing electrochemically active area and resulting in high local current densities and void formation. This accelerates subsequent filament growth and short circuiting compared to lithium‐excess cells. Despite this degradation mode, it is shown that anode‐free cells exhibit comparable Coulombic efficiency to lithium‐excess cells, and improved resistance to short circuiting is achieved by avoiding local lithium depletion through retention of thicker lithium at the interface. These new insights provide a foundation for engineering future high‐energy anode‐free SSBs.

Hyperspectral full polarization imaging system based on spatial modulation.

The hyperspectral full polarization imaging system (HFPIS) based on spatial modulation and liquid crystal tunable filter (LCTF) can modulate the polarization information of the target into the interferogram by means of interference imaging. It has the advantage of rapid imaging of the hyperspectral full polarization information from the target, and has good real time imaging and practicality. Through the spectroscopic imaging mode of a Savart prism, the corresponding interference optical path and imaging system are designed, including a beam expander, spatial modulator, LCTF, focusing system, and imaging sensor. This system can extract the different information from the target and demodulate it so as to obtain the hyperspectral polarization image. The experiment shows that the HFPIS can reveal the texture, contour, and other details of the target in the fog, and has obvious advantages over the traditional intensity imaging methods.

Use of high-dimensional and spatial immune profiling to explore sotigalimab (CD40 agonist) activation of antigen presenting cells and T cells in the tumor microenvironment in patients with esophageal/gastroesophageal junction cancer.

450 Background: Neoadjuvant chemoradiation (CRT) followed by surgical resection is standard of care for patients with locally advanced esophageal/gastroesophageal junction (E/GEJ) cancer. A pathologic complete response (pCR) at surgery is associated with improved survival outcomes. Sotigalimab (sotiga) is a potent CD40 agonist mAb capable of inducing and expanding anti-tumor immune responses. A recently reported non-randomized phase II clinical trial of sotiga combined with CRT in E/GEJ cancer patients showed promising pCR rates that compared favorably to historical data1. Here, deep immune profiling was performed on a subset of patients to gain insight into the mechanism of sotiga. Methods: In the initial safety cohort (n=6) of this phase II E/GEJ clinical trial, tumor and blood samples were obtained pre-treatment and again following a single lead-in dose of sotiga, prior to initiation of CRT. Immune modulation in the tumor microenvironment and blood of patients was examined using high dimensional techniques, including mass cytometry, multiplexed ion beam imaging, and single cell RNA sequencing. Results: Sotiga administration dramatically re-models the tumor microenvironment, inducing immune infiltration and shifting the immune composition predominantly toward an inflammatory phenotype. At baseline, E/GEJ tumors were infiltrated with myeloid cells and T cells, the majority of which were Tregs. Sotiga increased antigen-presenting cell (APC) infiltration in tumors and activated dendritic cells as demonstrated by expression of MHCII and CD86. Sotiga treatment also induced infiltration of activated cytotoxic T cells and decreased the proportion of Tregs. There was also evidence of T cell activation in peripheral blood with increased expression of 4-1BB, CTLA-4, ICOS and PD-L1. Therapeutic responses to sotiga were associated with distinct T cell signatures both at baseline and on-treatment. At baseline, pCR patients (representing 4 of the 6 pts (67%) in this cohort) had a higher ratio of memory CD4+ T cells to Tregs which further increased following sotiga treatment, whereas patients who did not have a pCR had a higher proportion of myeloid cells at baseline and did not show a decrease in Treg cells after sotiga treatment. Conclusions: Sotiga induced dramatic changes in the tumor microenvironment including increased frequency of activated T cells and APCs, and decreased frequency of Tregs. A distinct signature of T cell infiltration in baseline tumor biopsies was observed in patients who achieved a pCR versus those who did not, potentially identifying patients that may benefit from this novel treatment strategy.

Novel Discoveries in Spatial Biology with the Highest Image Quality

Genetic Engineering & Biotechnology NewsVol. 43, No. 2 Sponsored ContentNovel Discoveries in Spatial Biology with the Highest Image QualityIonpath's multiplexed ion beam imaging (MIBI™) brings the power of multiplexed spatial proteomics to translational research and drug discoveryPublished Online:10 Feb 2023https://doi.org/10.1089/gen.43.02.06AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 43Issue 2Feb 2023 Information© 2023 by GEN PublishingTo cite this article:Novel Discoveries in Spatial Biology with the Highest Image Quality.Genetic Engineering & Biotechnology News.Feb 2023.17-17.http://doi.org/10.1089/gen.43.02.06Published in Volume: 43 Issue 2: February 10, 2023PDF download

Multiplexed Tissue Imaging for Immune Cells Profiling During Peanut Allergy Immunotherapy

Oral immunotherapy (OIT) can desensitize food allergic individuals to offending food allergens. However, OIT-induced changes in tissue-resident immune cell subsets remain largely unexplored. We investigated peanut-OIT-induced spatial and temporal changes in gastrointestinal (GI) tract biopsies taken from our phase 2 peanut OIT trial- POISED using Multiplexed Ion Beam Imaging (MIBI).

A flexible proton beam imaging energy spectrometer (PROBIES) for high repetition rate or single-shot high energy density (HED) experiments (invited).

The PROBIES diagnostic is a new, highly flexible, imaging and energy spectrometer designed for laser-accelerated protons. The diagnostic can detect low-mode spatial variations in the proton beam profile while resolving multiple energies on a single detector or more. When a radiochromic film stack is employed for "single-shot mode," the energy resolution of the stack can be greatly increased while reducing the need for large numbers of films; for example, a recently deployed version allowed for 180 unique energy measurements spanning ∼3 to 75MeV with <0.4MeV resolution using just 20 films vs 180 for a comparable traditional film and filter stack. When utilized with a scintillator, the diagnostic can be run in high-rep-rate (>Hz rate) mode to recover nine proton energy bins. We also demonstrate a deep learning-based method to analyze data from synthetic PROBIES images with greater than 95% accuracy on sub-millisecond timescales and retrained with experimental data to analyze real-world images on sub-millisecond time-scales with comparable accuracy.

Vertical distribution of aerosol extinction coefficients at night derived from radiometry of scattered laser light

Determining the nighttime aerosol extinction coefficient profile in the lower atmosphere through optical measurements is a necessary but challenging task in environmental science due, among other factors, to the lack of a suitable extra-atmospheric night light source. In this work we present a method for retrieving the vertical distribution of the aerosol extinction coefficient via light scattered from a low-divergence light beam. We demonstrate its practical implementation using a low-power, portable green laser light source to sample the air column and an off-the-shelf, wide-angle digital camera located a few hundred meters away as detector. The light scattered off the laser beam in the direction toward the camera contains enough information to retrieve the aerosol extinction profile by inverting the integral equation relating the radiance of the recorded beam image to the aerosol distribution. An efficient and robust numerical inversion procedure is developed and demonstrated here. This approach can be used both in permanent measurement facilities or in mobile stations, and it facilitates the task of characterizing nighttime aerosols both on-demand or in the framework of routine environmental monitoring protocols.

LiF-Ag-Si-TMDs based long-range SPR sensor in visible and NIR spectrum

Four types of sensor structures are considered in this study: S1 (prism/Ag/SM), S2 (prism/LiF/Ag/SM), S3 (prism/LiF/Ag/Si/SM), and S4 (prism/LiF/Ag/Si/TMDs/SM), at six different wavelengths, i.e., 400, 500, 633, 785, 980 and 1024 nm. Beam width, angular sensitivity (Sang), imaging sensitivity (Simg), angular Figure-of-Merit (FoMang), imaging FoM (FoMimg), and penetration depth (PD) are calculated for comparative analysis of performance of the proposed sensor (S4). It is found that all the performance parameters except Sang. for S2, S3, and S4 are better than S1 at all the considered wavelengths. PD increases with wavelength for all the structures. FoMimg. is highest at 633 nm wavelength for all the structures except S1, whereas Simg. is highest at 633 nm wavelength for all the structures except S1 and S4 with WSe2. Highest Simg. and highest FoMimg. are 12985 RIU−1 and 1298500 (⁰RIU)−1 for S3. On comparing the structures with different TMDs, it is found that highest Simg. (7884.7 RIU−1) and highest FoMimg. (788471 (⁰RIU)−1) are obtained for S4 with WS2. Finally, it is seen that inclusion of LiF increases the imaging performance parameters, Simg. and FoMimg. at all wavelengths, which are further improved by the inclusion of Si (at 633 nm and 785 nm wavelengths). But, inclusion of TMDs over Si degrades the performance. However, TMDs are essential to increase the selective immobilization of biomolecular recognition element or affinity layer on its surface which is required for specific detection of target molecules. Therefore, effects of inclusion of TMDs on the sensor performance are also analysed.

Spatio-temporal coupling of RMS errors in laser amplification.

We developed a theoretical model for the relationship between the input and amplified laser beams of energy stability and spatial uniformity in the amplification process. 10 Hz, 8 ns, 1064 nm Nd:YAG Q-switched resonator with Nd:YAG main amplifier was employed for the experiment. The theoretical model simulation and Frantz-Nodvik simulation were performed by utilizing the obtained beam image, acquired energy from the experiment, and stored fluence from the gain medium. The result indicated that the fluctuation of the spatial distribution in a single beam influences the stability of temporally distributed energy during the amplification process of the laser beam, thereby improving energy stability.

Study on the Lateral Scattering of High‐Energy Heavy Ions Penetrating through Solids

The lateral scattering of ions in solids can induce beam broadening and range uncertainty in the application of high‐energy heavy ions to cancer treatment, ion beam imaging, and nanofabrication. Herein, using membranes of polyethylene terephthalate (PET), polyimide (PI), and diallyl glycol carbonates (CR‐39) of 25 μm–1.6 mm as nuclear track detectors, the lateral scattering of heavy ions with energy of 5.5–80.5 MeV u−1 Kr and C beams in solids are measured. The linear functional relationship between experimental and stopping and range of ions in matter (SRIM)‐simulated lateral scattering in these solid samples is established with determination coefficients R2 of 0.9979, through which the lateral scattering of ion penetrating through solids obtained from experiments can be reliably evaluated by the SRIM simulation results. The results also demonstrated that the resolution of the single ion localization system is better than 300 nm with the lateral scattering as the main limitation.

Simulation study on carbon-ion beam imaging by measuring secondary electron bremsstrahlung using imaging plate

The purpose of this study is to evaluate the effect of a lead radiation shield on the ability of a beam imaging device consist of an imaging plate (IP) and a collimator by Monte Carlo simulations. Simulations were performed using PHITS. A carbon-ion beam was injected to an acrylic target. A tungsten collimator having a pinhole was placed at the distance of 31.2 cm from the beam. A lead radiation shield was placed on the tungsten collimator. An IP was placed under the collimator. Beam images were acquired by recording the position distribution of energy deposition on the IP. We confirmed that therapeutic carbon-ion beam images could be acquired using the imaging device combining the IP and collimator. It was found that removal of the lead shield had no effect on the imaging results.

Near-field electromagnetic scattering of Bessel vortex beam by metal target

Bessel vortex beam, as a typical vortex beam, has the characteristics of carrying orbital angular momentum (OAM), no diffraction, and self-reconstruction, which makes it more competitive than plane wave in the field of future vortex beam target detection and imaging. In order to study the near-field electromagnetic scattering of a vortex beam by a metal target, the expression of the near-scattering field of Bessel vortex beam incident on any metal target is obtained by using the physical optics method, triangular surface element modeling, and the plane wave angular spectrum expansion method of vector Bessel vortex beam. The correctness of the proposed method is verified by comparing with the simulation results of FEKO software. The amplitude distribution and phase distribution of electric field, the OAM spectrum distribution and radar cross section (RCS) of the near-scattering field of the Bessel vortex beam incident on the simple target and the combined target are calculated. The effects of beam parameters, receiving distance, target shape and the positions of beam transmitting and receiving surfaces on near-field scattering results are numerically calculated. In addition, the distributions of near-field OAM spectra under different conditions and the near-field RCS distributions of different targets are given. The numerical results show that the near-field results of Bessel vortex beam incident on metal targets are related to the beam parameters, and conform to the law of Bessel beam changing with parameters. The near-field electric amplitude distribution is affected by the distance between the receiving surface and the target, but the phase distribution is hardly affected. The near-field scattering results reflect the changes of target shape. Under normal incidence, when the target is regular and symmetrical, the amplitude distribution and phase distribution are relatively regular, and the main mode is dominant. When the beam is obliquely incident on or does not fully illuminate the target, the amplitude distribution and phase distribution change, which will lead the derived mode to increase. In particular, when the target and the receiving surface both deviate from the incident beam, the OAM disturbance is the most severe. In the near-field RCS distribution, the RCS distributions of different targets are obviously different, and the results of &lt;i&gt;E&lt;/i&gt; plane and &lt;i&gt;H&lt;/i&gt; plane are also different. It can be seen from the numerical calculation results that the near-field scattering of Bessel vortex beam by a metal target contains a variety of information. The application of vortex electromagnetic wave will help improve the information acquisition of electromagnetic wave and target detection capability. The results in this work can provide a reference for target imaging and vortex radar detection.

Construction and tests of phosphor view screen station for monitoring transverse profile of electron beam at PCELL

Development of an accelerator-based light source for generating coherent terahertz (THz) and mid-infrared (MIR) free-electron laser (FEL) is ongoing at the PBP-CMU Electron Linac Laboratory (PCELL). For producing high quality radiation, suitable electron beam property is necessary. In particle accelerator technology, transverse beam distribution and profile can be measured by using several techniques. The beam monitoring using view screen station is one of popular and effective methods. At PCELL, we use stations consisting of phosphor screen equipped with CCD camera to monitor, measure and record the beam image along the accelerator system and beamlines. The phosphor screen was chosen due to its high spatial resolution. The phosphor film is uniformly coated on a thin aluminium plate. Its green emission when electrons hitting the screen is matched well with the respond of the CCD camera. The screen can be moved in and out from the vacuum chamber using the air pressurized linear actuator. This paper presents about design, construction and tests of the screen stations at PCELL. The resolution of measurements for beam transverse profile and emittance is also be discussed.

Mass Spectrometry-Based Tissue Imaging of the Tumor Microenvironment.

Multiplex ion beam imaging (MIBI) and imaging mass cytometry (IMC) enable highly multiplexed antibody (40+) staining of frozen or formalin fixed, paraffin-embedded (FFPE) human or murine tissues through detection of metal ions liberated from primary antibodies by time-of-flight mass spectrometry (TOF). These methods make detection of more than 50 targets theoretically possible while maintaining spatial orientation. As such, they are ideal tools to identify the multiple immune, epithelial, and stromal cell subsets in the tumor microenvironment and to characterize spatial relationships and tumor-immune status in either murine models or human samples. This chapter summarizes methods for antibody conjugation and validation, staining, and preliminary data collection using IMC or MIBI in both human and mouse pancreatic adenocarcinoma samples. These protocols are intended to facilitate use of these complex platforms in not only tissue-based tumor immunology studies but also tissue-based oncology or immunology studies more broadly.

A double dipole kicker for off and on-axis injection into ALBA-II

Injection into the ALBA-II storage ring will be performed off-axis in a 4 meters straight section with a single multipole kicker. We present a novel topology for the coils of the injection kicker, named double dipole kicker (DDK). The resulting magnetic field is the superposition of two opposite dipoles, generated by four inner and four outer conductor rods. When the eight rods are powered, the dipole term cancels and the remaining multipole field is used for off-axis injection. Alternatively, when the four inner rods are switched off, an almost pure dipole is produced, that is useful for on-axis injection during the commissioning. A prototype of DDK is presently under design to be installed and tested in the existing ALBA storage ring. The positioning of the rods is calculated in order to maximize the kick efficiency in mrad/kA and minimise the disturbance to the orbit and the emittance of the stored beam. A metallic coating with optimised thickness along the inner ceramic vacuum chamber should provide compensation for the eddy currents induced field in order to minimize the disturbance to the stored beam while ensuring sufficiently low heat dissipation by the beam image currents.