Friction stir lap welding has been utilized across research and industry for over a decade. However, difficulties in welding in the lap configuration without an interface-related defect have prevented the process from moving beyond low feed rates (generally less than 1.5 m per minute). As a means of making a huge leap in welding productivity, this study will evaluate friction stir welds made at 10 m per minute (mpm), detailing the changes to tool geometries and weld parameters that result in fully consolidated welds. Characterization of the subsequent material properties, namely through optical microscopy, CT scanning, microhardness testing, tensile and fatigue testing, hermetic seal pressure tests, and electron backscattered diffraction, is presented as a means of demonstrating the quality and repeatability of friction stir lap welds made at 10 mpm. Fully consolidated welds were produced at spindle speeds 5.5% faster and 2.9% slower than nominal values and weld depths ranging from 1% shallower to 8.2% deeper than nominal values. Additionally, the loading direction of the weld had a significant impact on tensile properties, with the advancing side of the weld measured to be 16% stronger in lap-shear tensile and 289% fatigue life improvement under all loading conditions measured when compared to the retreating side.

Nanophosphors have gained substantial attention in recent years for both the diagnosis and treatment of cancer. Near-infrared optical imaging based on Nd3+-doped rare-earth nanophosphors is widely used for deep penetration tissue imaging. The present work aims to develop a hierarchical structure of polydopamine (PDA)-coated alginate microspheres encapsulated with NaGdF4@NaYF4:Nd3+ and cisplatin to achieve enhanced photothermal therapy (PTT) alongside providing optical imaging, MRI, and CT multimodal imaging capabilities. The obtained microspheres were subjected to physicochemical characterization, absorption/emission features, radical scavenging potential, drug release, and antibacterial efficacy. Further, the irradiation of microspheres under an 808 nm NIR laser revealed an effective conversion of light energy into a temperature upsurge to 51.3 °C with a conversion efficiency of 53.3%. The hydrophilic NaGdF4@NaYF4:Nd3+ nanophosphors demonstrated significant fluorescence in the NIR range, longitudinal and transverse magnetic resonance relaxivity (r1 = 12.65 mM-1 s-1, r2 = 17.1 mM-1 s-1), and X-ray attenuation capacity of 132 HU. Moreover, cell culture analysis in the presence and absence of NIR irradiation against MG63 cell lines highlights the anticancer potential of the microspheres. These results suggest the potential of prepared microspheres as multifunctional nanotheranostic agents.

Additive manufacturing, in combination with virtual surgery planning, leads to the predictability of complex surgical cases. To guarantee patient safety, three-dimensional (3D) print quality must be ensured and verified. The aim of this study is to compare the accuracy of an optical white-light desktop scanner (OWLDS) and a cone beam CT (CBCT) scanner to that of a multi-slice CT scanner (MSCT) for scanning and digitizing 3D anatomical models. Twenty-two removable parts of a CE-certified anatomical skull, used as a patient-specific surrogate in a clinical workflow, were each scanned by MSCT, CBCT, and OWLDS scanners. The accuracy of the scanning modalities was investigated through a part comparison analysis of the stereolithography (STL) files derived from the different scanning modalities. The high-resolution OWLDS STL files show the smallest overall surface match deviation, at 0.04 mm, compared to the MSCT STL files. The CBCT STL files show an overall deviation of 0.07 mm compared to the MSCT STL files. This difference between the scan modalities increases as the volume of anatomical models decreases. The OWLDS is a safe, cost-effective, user-friendly, and highly accurate scanning modality suitable for accuracy evaluation during the manufacturing process of in-house 3D models. For smaller models, high-resolution optical scans are recommended.

Advanced radiation therapy techniques, including intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery (SRS), adaptive therapy, and proton therapy, offer high precision in delivering radiation doses to tumors while minimizing exposure to surrounding healthy tissues. These sophisticated methods necessitate stringent quality assurance (QA) measures to ensure their accuracy and safety. Three-dimensional (3D) dosimetry systems have the potential to play an important role in this context for verifying dose distributions in a comprehensive manner but have not been widely implemented partially due to a lack of streamlined systems that include dosimeter, readout, and analysis. The ClearView radiochromic dosimeter, the Vista 16 Optical CT scanner, and the VistaAce analysis software have the potential as a fully integrated 3D dosimetry tool for commissioning and verifying complex radiotherapy treatment plans. We aim to benchmark this integrated 3D dosimetry system and investigate its clinical utility. The performance of this system was benchmarked against an independent Monte Carlo dose calculation software, the Duke Large Field of View Optical CT Scanner (DLOS), and an open-source analysis software (3D Slicer v4.13). We measured two simple radiotherapy plans and a selection from the AAPM (American Association of Physicists in Medicine) Task Group 119 IMRT commissioning tests. Treatment plans were prepared within the Eclipse planning system (AAA v15.6.03) after which a Varian Truebeam linac was used to deliver the treatment plans. Vista 16 was used to reconstruct the measured 3D dose distribution which was compared to the dose distribution obtained from an independent Monte Carlo-based dose calculation algorithm, as well as the 3D dose distribution reconstructed using the well-established DLOS. Image registration, conversion from optical density to dose, and comparative analysis were done using the VistaAce software and validated against results obtained using 3D Slicer for a subset of tests. ClearView dosimeters exhibited a linear dose-response up to 60Gy. For the 3-field benchmarking irradiation, the agreement (2%/2mm 3D global gamma Index, 10% threshold) between ClearView/VistaAce versus the TPS and Monte Carlo was 97.8% and 98.8%, respectively. For the AAPM TG119 mock head and neck plan, the agreement (2%/2mm) with the treatment planning system and Monte Carlo was 99.1% and 95.1%, respectively. For the TG119 mock prostate, the agreement was 99.7% and 98.9%, respectively. Agreement for the ClearView/ Vista 16 dose reconstruction was equivalent or superior to that of the ClearView/DLOS reconstruction for the benchmarking irradiations. The ClearView/Vista 3D dosimetry system demonstrated robust performance in measuring and verifying realistic clinical dose distributions, with good agreement with an independent Monte Carlo algorithm and equivalent or better agreement than DLOS. The system's integrated approach, combining dosimetry, scanning, and analysis, streamlines QA processes in advanced radiation therapy, potentially enhancing clinical practice by providing consistent and accurate dosimetric verification.

Accurately identifying the fault type of an optical current transformer (optical CT) and evaluating the fault severity can provide strong support for the operation and maintenance of a direct current (DC) power system. In response to the problems that current research overlooks, the spatiotemporal features when making fault identification, which restrain the improvement of identification accuracy, and consider fault identification as an assessment of fault severity, which is unable to provide effective information for actual operation and maintenance work, this paper proposes an optical CT fault severity assessment model based on scene generation and spatiotemporal feature fusion. Firstly, a CNN-Transformer model is constructed to mine the fault characteristics in spatial and temporal dimensions by feature fusion, achieving accurate identification of fault types. Secondly, an improved synthetic minority oversampling method is adopted to generate virtual operating scenes, and the operating range under different operating states of the optical CT is statistically obtained. Finally, based on Shapley Additive Explanations (SHAP), the importance of the feature of optical CT is evaluated under different fault types. Reliant on the importance of features and operating range under different running states, the severity of the fault is assessed by quantifying the difference between the fault state and the normal state of the optical CT under the identified fault type. This study validated the effectiveness of the proposed method using actual operational data from an optical CT at a converter station in Hebei Province in China.

A polymer Gel Dosimeter (PGD) provides essential three-dimensional (3D) radiation dose distribution for the radiotherapy planning system (TPS). This study investigates the use of infrared absorption spectrum as a novel and more cost-effective alternative to Magnetic Resonance Imaging (MRI), Nuclear Magnetic Resonance (NMR), and Optical Computed Tomography (Optical CT) for reading out PGDs. The PGDs were fabricated using 2-Hydroxyethyl methacrylate (HEMA), maltose, N’N, methylene(bis)acrylamide (Bis), gelatin, deionized water (DI Water), and Tetrakis (hydroxymethyl) phosphonium chloride (THPC), and were irradiated using a Linear Accelerator (LINAC) within the range of 0–30 Gy. The possibility of translating molecular vibrational frequency, amplitude, and energy of vibration into absorbed dose was explored by analyzing the absorption spectra in the near-infrared region (NIR) with wavelengths between 750–1100 nm. The findings reveal that these vibrational properties can be employed to interpret irradiated PGDs. Furthermore, an increase in maltose concentration within the 0–520 mM range widens the linear dose range and enhances sensitivity. The PGDs exhibit temporal stability up to 7 days post-irradiation, and the span of their response remains relatively unaffected by scanning temperature. In conclusion, NIR spectroscopy offers a cost-effective method for interpreting PGDs, potentially improving the affordability and efficiency of PGD dosimetry in clinical radiotherapy. This holds particularly promising for less developed countries, aligning with the sustainable development goal (SDG) of ensuring affordable healthcare for all. We finally recommend further research into translating the molecular vibrational parameters into 3D images.

_ The oil industry has long flirted with virtual reality (VR) and visualization tech but falling prices and technological advances mean this once-futuristic concept is becoming more practical. The tech is appealing because oil companies have struggled to visualize complex subsurface data and effectively train their workforce. VR’s immersive nature is helping companies overcome such challenges. Space for Cores Physical space has long been a constraint when it comes to analyzing core samples at the YPF Technology (Y-TEC) research facility in Berisso, Buenos Aires. Ariel Guzzetti, lab and data manager for the subsurface services department at YPF Technology, told JPT the lab can display up to 500 linear m of physical core at any given time. Core projects tend to take between 4 and 8 months to complete because during those projects specialists require frequent access to the cores. Sometimes the facility displays optical electronic microscope images, CT scans, log plots, charts, and other data related to the cores on laptops, monitors, or printouts near the cores, such as for workshops or training sessions. “That’s how we run out of space,” he said. The facility can handle somewhere between five and eight projects simultaneously. “We usually have three, five, seven projects on hold, and not due to the capacity of our lab. Maybe we can do more tests, but we run out of space to lay out the cores,” he said. Finally, Guzzetti said, people frequently travel to the Buenos Aires facility to work with the cores, which can be inconvenient or costly. But virtual space is a different story: Enter the “miniverse,” a small virtual universe, in this case dedicated to geoscience. With VR, it’s possible to “bring people to the rock instantaneously,” he said, and displaying relevant data is much easier. “With this technology, you can mix up the rock and the data together without the restriction of laptops or TV screens. You can display as much information as you want, all in the same area.” With VR, experts can access and examine the cores, consult existing core data, and interact with other experts to study the samples. Core images, scans, and other information can be used to recreate the core digitally so it can be studied and interacted with in a virtual environment. Currently a geologist can see the structure, fractures, and facies in the core. Guzzetti emphasized that the virtual core is not the same as a digital twin of the core. “For core description, it does not replace the actual core. It’s more for analyzing data and seeing bigger structures,” he said. But he believes a digital twin future will be here soon, with virtual cores providing higher-resolution details. For now, though, Y-TEC is testing VR technology and plans to deploy its use within the +VacaMuerta consortium. “We are going to give a VR headset to every consortium member,” he said. “We can even coordinate to do meetings in the virtual reality so they will not need to come to our lab to see the rocks.” Working in the miniverse requires the use of a VR headset, and Guzzetti has been testing the Meta Quest 3 and Quest 2 versions.

BackgroundColon capsule endoscopy (CCE) is an alternative to optical colonoscopy and CT colonography for the investigation of the large bowel. It is less invasive but still needs bowel preparation to...

To review data on the advances in equine ophthalmic imaging that have been made during the past 5 years and highlight advantages of using multiple imaging modalities to improve clinical observational skills and improve diagnostic accuracy. A literature review from 2019 through 2024 of equine ophthalmic digital photography, fundus photography, ocular and orbital ultrasonography (US), ultrasound biomicroscopy (UBM), confocal microscopy (CM), spectral domain optical coherence tomography (SD-OCT), radiography, CT, and MRI. Digital photography remains the cornerstone of equine ophthalmic imaging for documenting examination findings, sharing information with colleagues, and consulting with specialists. Digital images also allow for in-depth postexamination review and evaluation, often revealing subtleties that may have otherwise gone undetected during the ophthalmic examination. Advanced imaging modalities are being used more frequently in equine ophthalmology, especially those that can be used with the horses standing under sedation, including US, UBM, SD-OCT, CM, and CT. Advances in equine ophthalmic imaging have led to many new clinical discoveries and to an increase in our knowledge of ocular anatomy and diseases in the horse. Many of these advanced diagnostic imaging modalities, such as MRI, CT, SD-OCT, and CM, are cost prohibitive and require substantial operator training to ensure proficiency. However, their availability in tertiary referral centers, such as veterinary teaching hospitals and large equine clinics/practices, is becoming more widespread. Advanced equine ophthalmic imaging data contributes substantially to our general understanding of clinical and applied anatomy and improves our understanding of the underlying pathogenesis associated with specific diseases.

Mono-pole blocking accident analysis caused by inaccurate measurement of optical CT in ±800 kV UHVDC transmission system under lightning strike

Calcareous sand has been widely used as a construction material for offshore projects; however, the problem of foundation settlement caused by particle crushing cannot be ignored. Although many methods for reinforcing calcareous sands have been proposed, they are difficult to apply on-site. In this study, a permeable polyurethane polymer adhesive (PPA) was used to reinforce calcareous sands, and its mechanical properties after reinforcement were investigated through compression creep, direct shear, and triaxial shear tests. The reinforcement mechanism was analyzed using optical microscopy, CT tomography, and mercury intrusion porosimetry. The experimental results indicate that there is a critical time during the compression creep process. Once the critical time is surpassed, creep accelerates again, causing failure of the traditional Burgers and Murayama models. The direct shear strength of the fiber- and geogrid-reinforced calcareous sand reinforced by PPA was approximately nine times greater than that without PPA. The influence of normal stress was not significant when the moisture content was less than 10%, but when the moisture content was more than 10%, the shear strength increased with an increase in vertical normal stress. Strain-softening features can be observed in triaxial shear tests under conditions of low confining pressure, and the relationship between the deviatoric stress and strain can be described using the Duncan-Chang model before softening occurs. The moisture content also has a significant influence on the peak strength and cohesive force but has little influence on the internal friction angle and Poisson's ratio. This influence is caused by the different PPA structures among the particles. The higher the moisture content, the greater the number of pores left after grouting PPA.

Gel dosimetry: An overview of dosimetry systems and read out methods

Attenuation images of optical CT using Fricke xylenol orange gel for dose mapping in radiotherapy

Abstract A comprehensive 3D dosimetry system consisting of the ClearView™ 3D dosimeter, VistaScan™ optical CT scanner, and VistaAce™ analysis software is commercially available and has the potential to be a strong verification tool with widespread applications. The clinical utility of this system (termed ClearView/Vista) has yet to be determined, and this work presents our first investigation. Clinical utility was evaluated using real patients’ treatment plans: spine, head and neck, Single Isocenter Multi-Targets SRS (SIMT-SRS), and prostate cases. Independent validation was performed with a Monte Carlo-based dose calculation algorithm that was previously commissioned for clinical independent dose calculation. The analysis included line profile comparison (1D), isodose line comparison (2D), and global gamma analysis (3D). Results indicated a remarkable agreement between ClearView/Vista, the treatment planning system, and Monte Carlo, where gamma pass rates for all cases exceeded 94% even while using 2%2mm and a dose threshold of 10%. The ClearView/Vista 3D dosimetry system showed clinically acceptable accuracy and robust measurement and analysis in clinical settings.

A cone-beam optical CT based on a convergent light source – Characterization and optimization

This research aimed to develop an innovative method for designing and fabricating nasal prostheses that reduces anaplastologist expertise dependency while maintaining quality and appearance, allowing patients to regain their normal facial appearance. The method involved statistical shape modeling using a morphable face model and 3D data acquired through optical scanning or CT. An automated design process generated patient-specific fits and appearances using regular prosthesis materials and 3D printing of molds. Manual input was required for specific case-related details. The developed method met all predefined requirements, replacing analog impression-making and offering compatibility with various data acquisition methods. Prostheses created through this method exhibited equivalent aesthetics to conventionally fabricated ones while reducing the skill dependency typically associated with prosthetic design and fabrication. This method provides a promising approach for both temporary and definitive nasal prostheses, with the potential for remote prosthesis fabrication in areas lacking anaplastology care. While new skills are required for data acquisition and algorithm control, these technologies are increasingly accessible. Further clinical studies will help validate its effectiveness, and ongoing technological advancements may lead to even more advanced and skill-independent prosthesis fabrication methods in the future.

Improved sensitivity and ambient light stability of radiochromic plastic dosimeters through composite azo compounds

This study compares changes in CT and AL in children with myopia after one month of continuous wear of newly prescribed glasses with HAL and MFL. The study included a total of 29 patients (58 eyes) with newly diagnosed mild myopia (mean -1.28±0.64 D) at an average age of 10.41±1.14 years wearing newly prescribed glasses with MFL (group 1) or with HAL (group 2). All patients underwent optical biometry and CT measurement using optical coherence tomography in addition to standard ophthalmological examination methods. In group 1 (SV), subfoveal CT decreased significantly by 18.13±7.88 μm after 1 month, while in group 2 (HAL), it increased by 12.88±29.86 μm. AL significantly increased by an average of 0.04±0.04 mm in group 1 and decreased by an average of 0.06±0.07 mm in group 2 (p<0.05). The use of optical means of correction leads to changes in biometric parameters of the eye within a month from the start of wearing them. A decrease in CT from baseline was observed with MFL glasses, while an increase was seen with HAL correction, which can be considered a favorable prognostic sign in the control of progressive myopia in children.

Background. Modern radiation therapy technologies aim to enhance radiation dose precision to the tumor and utilize hypofractionated treatment regimens. Verifying the dose distributions associated with these advanced radiation therapy treatments remains an active research area due to the complexity of delivery systems and the lack of suitable three-dimensional dosimetry tools. Gel dosimeters are a potential tool for measuring these complex dose distributions. A prototype tabletop solid-tank fan-beam optical CT scanner for readout of gel dosimeters was recently developed. This scanner does not have a straight raypath from source to detector, thus images cannot be reconstructed using filtered backprojection (FBP) and iterative techniques are required. Purpose. To compare a subset of the top performing algorithms in terms of image quality and quantitatively determine the optimal algorithm while accounting for refraction within the optical CT system. The following algorithms were compared: Landweber, superiorized Landweber with the fast gradient projection perturbation routine (S-LAND-FGP), the fast iterative shrinkage/thresholding algorithm with total variation penalty term (FISTA-TV), a monotone version of FISTA-TV (MFISTA-TV), superiorized conjugate gradient with the nonascending perturbation routine (S-CG-NA), superiorized conjugate gradient with the fast gradient projection perturbation routine (S-CG-FGP), superiorized conjugate gradient with with two iterations of CG performed on the current iterate and the nonascending perturbation routine (S-CG-2-NA). Methods. A ray tracing simulator was developed to track the path of light rays as they traverse the different mediums of the optical CT scanner. Two clinical phantoms and several synthetic phantoms were produced and used to evaluate the reconstruction techniques under known conditions. Reconstructed images were analyzed in terms of spatial resolution, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), signal non-uniformity (SNU), mean relative difference (MRD) and reconstruction time. We developed an image quality based method to find the optimal stopping iteration window for each algorithm. Imaging data from the prototype optical CT scanner was reconstructed and analysed to determine the optimal algorithm for this application. Results. The optimal algorithms found through the quantitative scoring metric were FISTA-TV and S-CG-2-NA. MFISTA-TV was found to behave almost identically to FISTA-TV however MFISTA-TV was unable to resolve some of the synthetic phantoms. S-CG-NA showed extreme fluctuations in the SNR and CNR values. S-CG-FGP had large fluctuations in the SNR and CNR values and the algorithm has less noise reduction than FISTA-TV and worse spatial resolution than S-CG-2-NA. S-LAND-FGP had many of the same characteristics as FISTA-TV; high noise reduction and stability from over iterating. However, S-LAND-FGP has worse SNR, CNR and SNU values as well as longer reconstruction time. S-CG-2-NA has superior spatial resolution to all algorithms while still maintaining good noise reduction and is uniquely stable from over iterating. Conclusions. Both optimal algorithms (FISTA-TV and S-CG-2-NA) are stable from over iterating and have excellent edge detection with ESF MTF 50% values of 1.266 mm−1 and 0.992 mm−1. FISTA-TV had the greatest noise reduction with SNR, CNR and SNU values of 424, 434 and 0.91 × 10−4, respectively. However, low spatial resolution makes FISTA-TV only viable for large field dosimetry. S-CG-2-NA has better spatial resolution than FISTA-TV with PSF and LSF MTF 50% values of 1.581 mm−1 and 0.738 mm−1, but less noise reduction. S-CG-2-NA still maintains good SNR, CNR, and SNU values of 168, 158 and 1.13 × 10−4, respectively. Thus, S-CG-2-NA is a well rounded reconstruction algorithm that would be the preferable choice for small field dosimetry.

Objective. To analyze the radiation doses to patients during spinal decompression and stabilization surgery under optical CT navigation and fluoroscopy.Material and Methods. Study design: retrospective cohort study. The sample consisted of 164 patients who underwent transpedicular fixation of the spine performed by percutaneous or open techniques. In the O-arm group (n = 109), cone-beam CT combined with optical navigation was used; in the C-arm group, fluoroscopy (n = 55) was used. The effective dose equivalent (EDE) and the maximum absorbed dose (MAD) in the skin were evaluated.Results. EDE in the O-arm group was Me 9.1 mSv, [IQR: 7.1–11.6], and in the C-arm group –Me 1.8 mSv [IQR: 1.8–5.6], p &lt; 0.0001. Maximum absorbed dose in the skin in the O-arm group was Me 49.3 mGy [IQR: 27.0–96.9], and in the C-arm group – Me 36.1 mGy [IQR: 16.6–111.5], p = 0.424.Conclusion. The use of CT navigation and fluoroscopy during pedicle screw fixation of the spine is not associated with the risk of developing deterministic effects. The use of intraoperative CT navigation during pedicle screw fixation is associated with a greater patient EDE compared with that of fluoroscopy (p &lt; 0.05). Differences in EDE received by patients undergoing open and percutaneous techniques of pedicle screw fixation are statistically insignificant, regardless of the type of beam guidance and the number of fixation levels. The number of intraoperative CT scans is proportional to the patient EDE (p = 0.018).