Computed Tomography Imaging Capability Research Articles

Gram-Scale Synthesis of Renal-Clearable Tantalum Nanodots with High Water Solubility for Computed Tomography Imaging In Vivo.

Tantalum (Ta) emerges as a promising element for advanced computed tomography (CT) imaging probes owing to its high X-ray attenuation coefficient and excellent biocompatibility. Nevertheless, the synthesis of renally clear Ta-based imaging probes through simple methods remains a significant challenge. Herein, we introduce a simple and gram-scale approach for the synthesis of renal-clearable Ta nanodots with high water solubility for CT imaging in vivo. The Ta nanodots, coordination polymers, are fabricated via coordination reactions involving Ta(OH)5, citric acid (CA), and hydrogen peroxide. The Ta nanodots exhibit an ultrasmall hydrodynamic diameter (2.8 nm), high water solubility (1.88 g/mL, 688 mg Ta/mL), superior X-ray absorption capacity, gram-scale production capability (>10 g in lab synthesis), renal-clearable ability, and good biocompatibility. The Ta nanodots possess superior CT imaging efficacy across diverse tube voltages, enabling highly sensitive gastrointestinal CT imaging, renal CT imaging, and CT angiography (CTA). Moreover, Ta nanodots maintain robust CT imaging capabilities even at high X-ray energies, and Ta nanodots-based spectral CT achieves metallic artifacts-minimized CTA. The proposed Ta nanodots present substantial potential as a potent CT imaging probe for diagnosing various diseases.

Detection of Manufacturing Defects in Lithium-Ion Batteries-Analysis of the Potential of Computed Tomography Imaging

Realising an ideal lithium-ion battery (LIB) cell characterised by entirely homogeneous physical properties poses a significant, if not an impossible, challenge in LIB production. Even the slightest deviation in a process parameter in its production leads to inhomogeneities and causes a deviation in performance parameters of LIBs within the same batch. The greater the number and/or intensity of inhomogeneities, the more they need to be avoided. Severe inhomogeneities (defects), such as metal particle contamination, significantly impact the cell’s performance. Besides electrical measurements, image-based measurement methods can be used to identify defects and, thus, ensure the production quality and safety of LIBs. While the applicability of computed tomography (CT) as an image-based measurement method for detecting defects has been proven, the limitations of this method still need to be determined. In this study, a systematic analysis of the capabilities of CT imaging was conducted. A multilayer pouch cell without an electrolyte was reassembled with several defects on one of the middle anodes. To investigate the boundaries of CT, defects such as a partial and complete removal of the coating, a cut, or a kink, as well as particle contaminations of various sizes and materials (aluminium, copper, iron) were chosen. By comparing the CT images of the cell using laser scanning microscope images of the defective anode, it could be proven that all selected defects except the kink were detectable.

Catalytic MnWO4 Nanorods for Chemodynamic Therapy Synergized Radiotherapy of Triple Negative Breast Cancer

AbstractNanomedicine‐based synergy of chemodynamic therapy (CDT) and radiotherapy (RT) modulated by tumor microenvironment enables rapid tumor ablation, which holds great hope for the refractory and recurrent cancers, such as triple negative breast cancer (TNBC). The clinical translation of hafnium oxide (HfO2), commercially named as NBTXR3, has aroused new research focus on single‐component inorganic nanomedicines as clinical candidates. Herein, the single‐component MnWO4 is first reported as a new kind of Fenton‐like agent yet radiosensitizer for TNBC treatment undergoing the synergistic CDT/RT mechanism. MnWO4 nanorods are synthesized via a simple one‐pot hydrothermal method and then undergo a layer‐by‐layer PEGylation to obtain bioavailable MnWO4‐PEG (MWP). MWP‐based Fenton‐like reaction efficacy depends on reaction time, temperatures, pH values, and MWP concentrations. Mn‐triggered chemodynamic effect delays RT‐induced DNA damage repair and sorts cell cycles distribution toward radiosensitive phases, while W‐mediated radiosensitization improves the tumoral H2O2 overexpression to enhance CDT, remarkably amplifying of the intracellular oxidative stress to boost 4T1 cell apoptosis. In vitro and in vivo evaluations further demonstrate the effectiveness and biosafety of MWP‐based synergistic therapy. Considering the potential magnetic resonance and computed tomography imaging capabilities, MWP can be expected as an intelligent cancer theranostics for imaging‐guided cancer therapy in clinic in the future.

Peptide‐Enabled Thrombus‐Targeting Nanoparticles for Highly Effective Targeted CT Imaging and Eradication of Thrombi

AbstractThrombotic disease poses a significant threat to human health as it blocks blood vessels and leads to severe symptoms. Effective treatment requires targeted therapy and precise localization of the thrombus, but traditional drugs are limited in their targeting ability and ability to locate the thrombus. To overcome these issues, a nanoparticle capable of both thrombus targeting and computed tomography (CT) imaging is developed. Phage display technology is used to screen for the thrombus‐targeting peptide termed GK, which is then linked to the surface of macroporous silica (Mp‐SiO2) with a Bi core to create Mp‐Bi@SiO2‐GK. The large pores of Mp‐Bi@SiO2‐GK enable the transport of the drug Urokinase (UK), while the Bi core provides the capabilities of CT imaging and photothermal therapy. The Mp‐Bi@SiO2‐GK nanoparticles precisely target thrombi in mouse carotid arteries and locate them via CT imaging. Furthermore, the combination of Bi‐enabled photothermal therapy and UK‐induced chemotherapy enhance the thrombolysis efficiency. Treatment with Mp‐Bi@SiO2‐GK nanoparticles do not harm tissues/organs or affect liver/kidney metabolism. These results show that Mp‐Bi@SiO2‐GK exhibits precise thrombus targeting and efficient imaging/treatment capability, making it a promising tool for the diagnosis and treatment of thrombosis.

A Phase Engineering Strategy of Perovskite‐Type ZnSnO3:Nd for Boosting the Sonodynamic Therapy Performance

AbstractThe sensitization performance of sonosensitizers plays a key role in the sonodynamic therapy (SDT) effect. Herein, ZnSnO3:Nd nanoparticles with R3c phase/amorphous heterogeneous structure are developed by phase engineering strategy and applied as an ideal sonosensitizer. In the crystalline perovskite‐type ZnSnO3:Nd, the substitution of the Zn2+ with Nd3+ causes the O 2p non‐bonded state to move toward the Fermi level, which optimizes the band structure for ultrasound sensitization by reducing bandgap. Meanwhile, the unequal charge substitution can also form electron traps and oxygen vacancies to shorten the electron migration distance, which accelerates the electron–hole separation and inhibits carrier recombination, thus improving the acoustic sensitivity. Moreover, the dangling bonds exposed on the surface of amorphous ZnSnO3:Nd provide more active sites, and the localized states of the amorphous phase may also promote carrier separation, resulting in synergistic SDT effect. In particular, the Zn2+ released from ZnSnO3:Nd in the acidic tumor microenvironment (TME) reduces the adenosine triphosphate production by inhibiting the electron transport chain , which promotes the tumor cell apoptosis through destroying the redox balance of TME. Combining the inherent second near infrared and computed tomography imaging capabilities, this ZnSnO3:Nd nanoplatform shows a promising perspective in clinic SDT field.

Efficient oral delivery of water-soluble CT contrast agent using an W1/O/W2 alginate hydrogel matrix

HypothesisIohexol (IOH) is a commonly used second-generation nonionic iodinated contrast agent. However, low gastrointestinal mucosal adherence and high downstream speed limit its application in intestinal Computed tomography (CT) imaging. We hypothesize that oral IOH delivery carriers composed of environmentally responsive materials enable the intestinal targeted delivery and prolong the intestinal residence time of IOH, enhancing the intestinal disease detection efficiency. ExperimentsAn emulsion-filled alginate hydrogel system was developed as the intestinal targeting vehicle for IOH. The formulation optimization was determined by response surface analysis. After a thorough study of the physicochemical properties of this hydrogel matrix, the pH sensitivity and the ability to control release were investigated, followed by a vitro cell experiment evaluating its bioactivity and CT imaging capability. FindingsThis alginate hydrogel matrix was sparsely structured and rapidly released IOH at pH 7.4. Meanwhile the swelling degree was 4.4 times higher than that at pH 1.2, indicating a good selective responsiveness to the gastrointestinal simulated environment. It improved the CT visual contrast of A549 cells without affecting cell morphology, suggesting that it would be an effective oral administration for water-soluble nonionic contrast agents and a potential candidate for intestinal disease detection tools.

Use of cone-beam computed tomography for advanced imaging of the equine patient.

Access to volumetric imaging modalities, such as magnetic resonance imaging (MRI) and computed tomography (CT), has increased over the past decade and has revolutionised the way clinicians evaluate equine anatomy. More recent advancements have resulted in the development of multiple commercially available cone-beam CT (CBCT) scanners for equine use. CBCT scanners modify the traditional fan-shaped beam of ionising radiation into a three-dimensional pyramidal- or cone-shaped beam of radiation. This modification enables the scanner to acquire sufficient data to create diagnostic images of a region of interest after a single rotation of the gantry. The rapid acquisition of data and divergent X-ray beam causes some artifacts to be more prominent on CBCT images-as well as the unique cone-beam artifact-resulting in decreased contrast resolution. While the use of CT for evaluation of the equine musculoskeletal anatomy is not new, there is a paucity of literature and scientific studies on the capabilities of CBCT for equine imaging. CBCT units do not require a specialised table for imaging and in some cases are portable for imaging in the standing or anaesthetised patient. This review article summarises the basic physics of CT technology, including how CBCT imaging differs, and provides objective information about the strengths and limitations of this modality. Finally, potential future applications and techniques for imaging with CT which will need to be explored in order to fully consider the capabilities of CT imaging in the horse are discussed.

P6155Early computed tomographic evaluation for out-of-hospital cardiac arrest survivors: the CT-FIRST trial

Abstract Background Patients surviving an out-of-hospital cardiac arrest (OHCA) commonly present without an obvious etiology, but computed tomography (CT) can provide rapid, comprehensive anatomic evaluation of potential OHCA causes. Purpose To assess the diagnostic capabilities of whole body CT imaging in OHCA survivors. Methods From 11/2015 to 2/2018, the CT-FIRST (CT Feasibility In Resuscitated patient for Sudden death Triage) protocol enrolled 104 OHCA survivors without obvious OHCA cause to an early (<6 hours from hospital arrival) dual source Sudden Death CT (SDCT) scan protocol that included a non-contrast head, ECG-gated cardiac/thoracic angiography, and non-gated venous phase abdominal CT's. Cardiac CT analysis was blinded, but other SDCT findings were clinically available. Patients needing urgent cardiac catheterization or hemodynamically unable to tolerate CT were excluded. Primary endpoints were SDCT diagnosis compared to OHCA causes from adjudicated record review, and any significantly altered therapy based on SDCT. Acute coronary syndrome by SDCT was conservatively assumed if >50% stenosis was identified in major coronary artery(ies). Results SDCT scans identified 39% (41/104) of all OHCA causes and 95% (41/43) of causes potentially identifiable with SDCT (Table). No inappropriate treatments resulted from SDCT findings. SDCT changed or expedited treatments in 21/23 (95%) patients, including antibiotics, anticoagulants, and invasive evaluations or treatments. SDCT found or confirmed resuscitation complications including liver/spleen laceration (n=5), pneumothorax (n=7), and hemopericardium (n=1). N=104 OHCA Cause SDCT Diagnosis of OHCA Cause N (%) N (%) Acute coronary syndrome 13 (13%) 13 (100%) Cardiomyopathy 8 (8%) 7 (88%) Pneumonia 11 (11%) 11 (100%) Hemorrhagic stroke 3 (3%) 3 (100%) Pulmonary embolism 4 (3%) 4 (100%) Perforated viscus 2 (2%) 2 (100%) Gut necrosis 1 (1%) 1 (100%) Pulmonary hemorrhage 1 (1%) 1 (100%) Substance use 22 (21%) 0 (0%) Unknown 7 (7%) 0 (0%) Other 32 (31%) 0 (0%) Conclusion This pilot study suggests the SDCT protocol has considerable promise to diagnose OHCA causes and complications of resuscitation, as well as change clinical treatment. Acknowledgement/Funding Medic One Foundation

Doxorubicin-Loaded Unimolecular Micelle-Stabilized Gold Nanoparticles as a Theranostic Nanoplatform for Tumor-Targeted Chemotherapy and Computed Tomography Imaging.

Current research is mainly trending toward addressing the development of multifunctional nanocarriers that could precisely reach disease sites, release drugs in a controlled-manner, and act as an imaging agent for both diagnosis and targeted therapy. In this study, a pH-sensitive theranostic nanoplatform as a promising dual-functional nanovector for tumor therapy and computed tomography (CT) imaging was developed. The 21-arm star-like triblock polymer of β-cyclodextrin-{poly(ε-caprolactone)-poly(2-aminoethyl methacrylate)-poly[poly(ethylene glycol) methyl ether methacrylate]}21 [β-CD-(PCL-PAEMA-PPEGMA)21] with stable unimolecular micelles formed in aqueous solution was first synthesized by combined ROP with ARGET ATRP techniques and then was used as a template for fabricating gold nanoparticles (AuNPs) with uniform sizes and excellent colloidal stability in situ followed by the encapsulation of doxorubicin (DOX) with maximum entrapment efficiency up to 60% to generate the final product β-CD-(PCL-PAEMA-PPEGMA)21/AuNPs/DOX. Furthermore, dissipative particle dynamics (DPD) simulations revealed further details of the formation process of unimolecular micelles and the morphologies and distributions of AuNPs and DOX. Almost 80% of DOX was released in 120 h in an acidic tumoral environment in an in vitro drug release experiment, and the experiments both in vitro and in vivo demonstrated the fact that β-CD-(PCL-PAEMA-PPEGMA)21/AuNPs/DOX exhibited similar antitumor efficacy to free DOX and effective CT imaging performance. Therefore, we believe this structurally stable unimolecular micelle-based nanoplatform synergistically integrated with anticancer drug delivery and CT imaging capabilities hold great promise for future cancer theranostics.

Multifunctional Cu1.94S-Bi2S3@polymer nanocomposites for computed tomography imaging guided photothermal ablation

The doping of radiocontrast agent such as bismuth (Bi) in copper chalcogenide nanocrystals for computed tomography (CT) imaging guided photothermal therapy (PTT) has drawn increasing attention. However, the doping of Bi often suffers from the weak CT signal due to the low Bi doping concentration and deteriorates the PTT efficacy of copper chalcogenides. Here we report a multifunctional nanoprobe by encapsulating both Cu1.94S and Bi2S3 nanocrystals into a biocompatible poly(amino acid) matrix with size of ~85 nm for CT imaging guided PTT. The amount of nanocrystals and the ratio of Cu1.94S-to-Bi2S3 in the multifunctional nanocomposites (NCs) are tunable toward both high photothermal conversion efficiency (~31%) and excellent CT imaging capability (27.8 HU g L−1). These NCs demonstrate excellent effects for photothermal ablation of tumors after intratumoral injection on 4T1 tumor-bearing mice. Our study may provide a facile strategy for the fabrication of multifunctional theranostics towards simultaneous strong CT signal and excellent PTT.

LabPET II, an APD-based Detector Module with PET and Counting CT Imaging Capabilities

Computed tomography (CT) is currently the standard modality to provide anatomical reference for positron emission tomography (PET) in molecular imaging applications. Since both PET and CT rely on detecting radiation to generate images, using the same detection system for data acquisition is a compelling idea even though merging PET and CT hardware imposes stringent requirements on detectors. These requirements include large signal dynamic range with high signal-to-noise ratio for good energy resolution in PET and energy-resolved photon-counting CT, high pixelization for suitable spatial resolution in CT, and high count rate capability for reasonable CT acquisition time. To meet these criteria, the avalanche photodiode (APD)-based LabPET II module is proposed as the building block for a truly combined PET/CT scanner. The module is made of two monolithic $ 4\times 8$ APD pixel arrays mounted side-by-side on a custom ceramic holder. Individual APD pixels have an active area of $ 1.1\times 1.1~\hbox{mm}^{2}$ at a 1.2 mm pitch. The APD arrays are coupled to a 12-mm high, $8 \times 8$ LYSO scintillator array made of $1.12 \times 1.12~\hbox{mm}^{2}$ pixels also at a pitch of 1.2 mm to ensure direct one-to-one coupling to individual APD pixels. The scintillator array was designed with unbound specular reflective material between pixels to maximize the difference between refractive indices and enhance total internal reflection at the crystal side surfaces for better light collection, and the APD quantum efficiency was improved to $ \sim60\%$ at 420 nm to optimize intrinsic detector performance. Mean energy resolution was $20 \pm 1\%$ at 511 keV and $ 41\pm 4\%$ at 60 keV. The measured intrinsic spatial and time resolution for PET were respectively $0.81 \pm 0.04~\hbox{mm}~{\rm FWHM}/1.57 \pm 0.04~\hbox{mm}$ FWTM and $ 3.6\pm 0.3~\hbox{ns}$ FWHM with an energy threshold of 400 keV. Initial phantom images obtained using a CT test bench demonstrated excellent contrast linearity as a function of material density. With a magnification factor of 2, a CT spatial resolution of 0.66 mm FWHM/1.2 mm FWTM, corresponding to 1.18 lp/mm at ${\rm MTF}_{10\%}/0.67~\hbox{lp/mm}$ at ${\rm MTF}_{50\%}$ , was measured, allowing 0.75 mm air holes in an Ultra-Micro Hot Spot resolution phantom to be clearly distinguished.

Ultra-small BaGdF5-based upconversion nanoparticles as drug carriers and multimodal imaging probes

A new type of drug-delivery system (DDS) was constructed, in which the anti-cancer drug doxorubicin (DOX) was conjugated to the ultra-small sized (sub-10 nm) BaGdF5:Yb3+/Tm3+ based upconversion nanoparticles (UCNPs). This multifunctional DDS simultaneously possesses drug delivery and optical/magnetic/X-ray computed tomography imaging capabilities. The DOX can be selectively released by cleavage of hydrazone bonds in acidic environment, which shows a pH-triggered drug release behavior. The MTT assay shows these DOX-conjugated UCNPs exhibit obvious cytotoxic effect on HeLa cells. Moreover, to improve the upconversion luminescence intensity, core–shell structured UCNPs were constructed. The in vitro upconversion luminescence images of these UCNPs uptaken by HeLa cells show bright emission with high contrast. In addition, these UCNPs were further explored for T1-weighted magnetic resonance (MR) and X-ray computed tomography (CT) imaging in vitro. Long-term in vivo toxicity studies indicated that mice intravenously injected with 10 mg/kg of UCNPs survived for 40 days without any apparent adverse effects to their health. The results indicate that this multifunctional drug-delivery system with optimized size, excellent optical/MR/CT trimodal imaging capabilities, and pH-triggered drug release property is expected to be a promising platform for simultaneous cancer therapy and bioimaging.

CT DOSE: HOW TO MEASURE, HOW TO REDUCE

The fundamental radiation dose parameter in computed tomography (CT) is the CT dose index (CTDI), which is an integral under the radiation dose profile of a single axial scan normalized to the nominal x-ray beam width. It estimates the average dose from a multiple-scan examination and is a directly measurable and standardized quantity. From this information, the dose length product (DLP) is calculated, which estimates the total dose delivered over a specific scan length. Finally, effective dose can be estimated and used to reflect the risk of a non-uniform exposure in terms of a whole-body exposure. To manage dose from CT while maintaining diagnostic image quality, scanner manufacturers have implemented tube current modulation, which may occur angularly around the patient, along the long axis of the patient, or both. Dose reductions of 20 to 50% have been reported using tube current modulation schemes. In the past two decades, the capabilities of CT imaging have expanded tremendously, including narrower image widths, improved temporal and spatial resolution, shorter scan times, and cardiac imaging techniques. Yet, the dose per typical exam (e.g., routine abdominal CT) has decreased by a factor of two or more over the same time period. Therefore, patients should be reassured that the benefits of medically-justified and appropriately-performed CT examinations are associated with radiation doses that continue to decrease as technology continues to evolve.

Intraoperative Laparoscope Augmentation for Port Placement and Resection Planning in Minimally Invasive Liver Resection

In recent years, an increasing number of liver tumor indications were treated by minimally invasive laparoscopic resection. Besides the restricted view, two major intraoperative issues in laparoscopic liver resection are the optimal planning of ports as well as the enhanced visualization of (hidden) vessels, which supply the tumorous liver segment and thus need to be divided (e.g., clipped) prior to the resection. We propose an intuitive and precise method to plan the placement of ports. Preoperatively, self-adhesive fiducials are affixed to the patient's skin and a computed tomography (CT) data set is acquired while contrasting the liver vessels. Immediately prior to the intervention, the laparoscope is moved around these fiducials, which are automatically reconstructed to register the patient to its preoperative imaging data set. This enables the simulation of a camera flight through the patient's interior along the laparoscope's or instruments' axes to easily validate potential ports. Intraoperatively, surgeons need to update their surgical planning based on actual patient data after organ deformations mainly caused by application of carbon dioxide pneumoperitoneum. Therefore, preoperative imaging data can hardly be used. Instead, we propose to use an optically tracked mobile C-arm providing cone-beam CT imaging capability intraoperatively. After patient positioning, port placement, and carbon dioxide insufflation, the liver vessels are contrasted and a 3-D volume is reconstructed during patient exhalation. Without any further need for patient registration, the reconstructed volume can be directly augmented on the live laparoscope video, since prior calibration enables both the volume and the laparoscope to be positioned and oriented in the tracking coordinate frame. The augmentation provides the surgeon with advanced visual aid for the localization of veins, arteries, and bile ducts to be divided or sealed.

ANATOMY OF THE CANINE ORBITAL REGION

Computed tomography (CT) was used to study the normal anatomy of the orbital region in one Beagle. Direct transverse and reformatted dorsal, sagittal, and oblique plane images were used to distinguish various soft tissue structures. Intraorbital fat provided a natural contrast against which extraocular muscles and nerves could be discerned. The noninvasive nature and the multiplanar imaging capabilities of CT provided a means by which the orbital contents could be precisely localized and differentiated from one another.