Twisted clustered pinhole collimation for improved high-energy preclinical SPECT/PET.

Advanced pinhole collimation geometries optimized for preclinical high-energyimaging facilitate applications such asandemitter imaging, simultaneous multi-isotope PET and PET/SPECT, and positron range-free PET. These geometries replace each pinhole with a group of clustered pinholes (CPs) featuring smaller individual pinhole opening angles (POAs), enabling sub-mm resolution imaging up to ∼1 MeV. Further narrowing POAs while retaining field-of-view (FOV) may enhance high-energy imaging but faces geometrical constraints.

NaI gamma camera performance for high energies: Effects of crystal thickness, photomultiplier tube geometry and light guide thickness.

Background: Gamma camera imaging, including single photon emission computed tomography (SPECT), is crucial for research, diagnostics, and radionuclide therapy. Gamma cameras are predominantly based on arrays of photon multipliers tubes (PMTs) that read out NaI(Tl) scintillation crystals. In this way, standard gamma cameras can localize ɣ-rays with energies typically ranging from 30 to 360 keV.

Evaluating the Targeting of a -Infected Implant with a Radiolabeled Antibody In Vivo.

Implant infections caused by are difficult to treat due to biofilm formation, which complicates surgical and antibiotic treatment. We introduce an alternative approach using monoclonal antibodies (mAbs) targeting and provide evidence of the specificity and biodistribution of --targeting antibodies in a mouse implant infection model. The monoclonal antibody 4497-IgG1 targeting wall teichoic acid in was labeled with indium-111 using CHX-A"-DTPA as a chelator.

A scanning focus nuclear microscope with multi-pinhole collimation.

Microscopic nuclear imaging down to spatial resolutions of a few hundred microns can already be achieved using low-energy gamma emitters (e.g.I, ∼30 keV) and a basic single micro-pinhole gamma camera.

Glymphatic-assisted perivascular brain delivery of intrathecal small gold nanoparticles.

Nanoparticles are ultrafine particulate matter having considerable potential for treatment of central nervous system (CNS) disorders. Despite their tiny size, the blood-brain barrier (BBB) restricts their access to the CNS. Their direct cerebrospinal fluid (CSF) administration bypasses the BBB endothelium, but still fails to give adequate brain uptake.

Human monoclonal antibodies against surface antigens recognize in vitro and in vivo biofilm.

Implant-associated infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and potential treatment of biofilm-related infections.

Convolutional neural network based attenuation correction forI-FP-CIT SPECT with focused striatum imaging.

SPECT imaging withI-FP-CIT is used for diagnosis of neurodegenerative disorders like Parkinson's disease. Attenuation correction (AC) can be useful for quantitative analysis ofI-FP-CIT SPECT. Ideally, AC would be performed based on attenuation maps (μ-maps) derived from perfectly registered CT scans.

Efficient Monte-Carlo based system modelling for image reconstruction in preclinical pinhole SPECT.

The use of multi-pinhole collimation has enabled ultra-high-resolution imaging of SPECT and PET tracers in small animals. Key for obtaining high-quality images is the use of statistical iterative image reconstruction with accurate energy-dependent photon transport modelling through collimator and detector. This can be incorporated in a system matrix that contains the probabilities that a photon emitted from a certain voxel is detected at a specific detector pixel.

3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow.

Background: Three-dimensional (3D)-printed saw guides are frequently used to optimize osteotomy results and are usually designed based on computed tomography (CT), despite the radiation burden, as radiation-less alternatives like magnetic resonance imaging (MRI) have inferior bone visualization capabilities. This study investigated the usability of MR-based synthetic-CT (sCT), a novel radiation-less bone visualization technique for 3D planning and design of patient-specific saw guides.

Methods: Eight human cadaveric lower arms (mean age: 78y) received MRI and CT scans as well as high-resolution micro-CT.

Automatic attenuation map estimation from SPECT data only for brain perfusion scans using convolutional neural networks.

In clinical brain SPECT, correction for photon attenuation in the patient is essential to obtain images which provide quantitative information on the regional activity concentration per unit volume (kBq.[Formula: see text]). This correction generally requires an attenuation map ([Formula: see text] map) denoting the attenuation coefficient at each voxel which is often derived from a CT or MRI scan.

EXIRAD-HE: multi-pinhole high-resolution ex vivo imaging of high-energy isotopes.

We recently developed a dedicated focusing multi-pinhole collimator for a stationary SPECT system that offers down to 120 µm (or 1.7 nL) spatial resolution SPECT images of cryo-cooled tissue samples (EXIRAD-3D). This collimator is suitable for imaging isotopes that are often used in small animal and diagnostic SPECT such as I (27 keV), Tl (71 keV), Tc (140 keV), and In (171 and 245 keV).

The clinical utilities of multi-pinhole single photon emission computed tomography.

Single photon emission computed tomography (SPECT) is an important imaging modality for various applications in nuclear medicine. The use of multi-pinhole (MPH) collimators can provide superior resolution-sensitivity trade-off when imaging small field-of-view compared to conventional parallel-hole and fan-beam collimators. Besides the very successful application in small animal imaging, there has been a resurgence of the use of MPH collimators for clinical cardiac and brain studies, as well as other small field-of-view applications.

Characterization of a multi-pinhole molecular breast tomosynthesis scanner.

In recent years, breast imaging using radiolabelled molecules has attracted significant interest. Our group has proposed a multi-pinhole molecular breast tomosynthesis (MP-MBT) scanner to obtain 3D functional molecular breast images at high resolutions. After conducting extensive optimisation studies using simulations, we here present a first prototype of MP-MBT and evaluate its performance using physical phantoms.

EXIRAD-3D: Fast automated three-dimensional autoradiography.

Introduction: Autoradiography is an established technique for high-resolution imaging of radiolabelled molecules in biological tissue slices. Unfortunately, creating a 3D image from a set of these 2D images is extremely time-consuming and error-prone. MicroSPECT systems provide such 3D images but have a low resolution.

Accelerated image reconstruction by a combined dual-matrix dual-voxel approach.

Today, versatile emission computed tomography (VECTor) technology using dedicated high-energy collimation enables simultaneous positron emission tomography (PET) and single photon emission computed tomography (SPECT) down to 0.6 mm and 0.4 mm resolution in mice, respectively.

Optimized sampling for high resolution multi-pinhole brain SPECT with stationary detectors.

Brain perfusion SPECT can be used in the diagnosis of various neurologic or psychiatric disorders, e.g. stroke, epilepsy, dementia and posttraumatic stress disorder.

Evaluation of pinhole collimator materials for micron-resolution ex vivo SPECT.

Pinhole collimation is widely recognized for offering superior resolution-sensitivity trade-off in SPECT imaging of small subjects. The newly developed EXIRAD-3D autoradiography technique (MILabs B.V.

Data Curation for Preclinical and Clinical Multimodal Imaging Studies.

Purpose: In biomedical research, imaging modalities help discover pathological mechanisms to develop and evaluate novel diagnostic and theranostic approaches. However, while standards for data storage in the clinical medical imaging field exist, data curation standards for biomedical research are yet to be established. This work aimed at developing a free secure file format for multimodal imaging studies, supporting common in vivo imaging modalities up to five dimensions as a step towards establishing data curation standards for biomedical research.

Novel light-guide-PMT geometries to reduce dead edges of a scintillation camera.

Anger cameras based on monolithic NaI scintillators read out by an array of PMTs are predominant in planar gamma imaging and SPECT. However, position estimation of gamma interactions is usually severely degraded near the edges of the scintillator which can be extremely undesirable for applications like breast imaging. Here we propose a relatively cost-effective solution based on the use of scintillators with absorptive edges with an unconventional light-guide-PMT layout employing a maximum likelihood positioning algorithm.

Comparison of fan beam, slit-slat and multi-pinhole collimators for molecular breast tomosynthesis.

Recently, we proposed and optimized dedicated multi-pinhole molecular breast tomosynthesis (MBT) that images a lightly compressed breast. As MBT may also be performed with other types of collimators, the aim of this paper is to optimize MBT with fan beam and slit-slat collimators and to compare its performance to that of multi-pinhole MBT to arrive at a truly optimized design. Using analytical expressions, we first optimized fan beam and slit-slat collimator parameters to reach maximum sensitivity at a series of given system resolutions.

Imaging of Folate Receptor Expressing Macrophages in the Rat Groove Model of Osteoarthritis: Using a New DOTA-Folate Conjugate.

Objective To evaluate the presence and localization of folate receptor expressing macrophages in the rat groove model of osteoarthritis and determine the suitability of a new folate conjugate with albumin-binding entity (cm09) for in vivo SPECT (single-photon emission computed tomography) analysis. Design In male Wistar rats, local cartilage damage was induced in addition to a standard ( n = 10) or high-fat diet ( n = 6). After 12 weeks, In labeled folate conjugates were administered, and SPECT/CT (computed tomography) imaging was performed after 24 hours.

System geometry optimization for molecular breast tomosynthesis with focusing multi-pinhole collimators.

Imaging of Tc-labelled tracers is gaining popularity for detecting breast tumours. Recently, we proposed a novel design for molecular breast tomosynthesis (MBT) based on two sliding focusing multi-pinhole collimators that scan a modestly compressed breast. Simulation studies indicate that MBT has the potential to improve the tumour-to-background contrast-to-noise ratio significantly over state-of-the-art planar molecular breast imaging.

Molecular breast tomosynthesis with scanning focus multi-pinhole cameras.

Planar molecular breast imaging (MBI) is rapidly gaining in popularity in diagnostic oncology. To add 3D capabilities, we introduce a novel molecular breast tomosynthesis (MBT) scanner concept based on multi-pinhole collimation. In our design, the patient lies prone with the pendant breast lightly compressed between transparent plates.