Optical Surface Scanning Research Articles

Modelling Method for Aeroelastic Low Engine Order Excitation Originating from Upstream Vanes’ Geometrical Variability

The manufacturing geometrical variability in axial compressors is a stochastic source of uncertainty, implying that the real geometry differs from the nominal design. This causes the real geometry to lose the ideal axial symmetry. Considering the aerofoils of a stator vane, the geometrical variability affects the flow traversing it. This impacts the downstream rotor, especially when considering the aeroelastic excitation forces. Optical surface scans coupled with a parametrisation method allow for acquiring the information relative to the real aerofoils geometries. The measured data are included in a multi-passage and multi-stage CFD setup to represent the mistuned flow. In particular, low excitation harmonics on the rotor vane are introduced due to the geometrical deviations of the upstream stator. The introduced low engine orders, as well as their amplitude, depend on the stator geometries and their order. A method is proposed to represent the phenomena in a reduced CFD domain, limiting the size and number of solutions required to probabilistically describe the rotor excitation forces. The resulting rotor excitation forces are reconstructed as a superposition of disturbances due to individual stator aerofoils geometries. This indicates that the problem is linear in the combination of disturbances from single passages.

Accuracy of facial skeletal surfaces segmented from CT and CBCT radiographs

The accuracy of three-dimensional (3D) facial skeletal surface models derived from radiographic volumes has not been extensively investigated yet. For this, ten human dry skulls were scanned with two Cone Beam Computed Tomography (CBCT) units, a CT unit, and a highly accurate optical surface scanner that provided the true reference models. Water-filled head shells were used for soft tissue simulation during radiographic imaging. The 3D surface models that were repeatedly segmented from the radiographic volumes through a single-threshold approach were used for reproducibility testing. Additionally, they were compared to the true reference model for trueness measurement. Comparisons were performed through 3D surface approximation techniques, using an iterative closest point algorithm. Differences between surface models were assessed through the calculation of mean absolute distances (MAD) between corresponding surfaces and through visual inspection of facial surface colour-coded distance maps. There was very high reproducibility (approximately 0.07 mm) and trueness (0.12 mm on average, with deviations extending locally to 0.5 mm), and no difference between radiographic scanners or settings. The present findings establish the validity of lower radiation CBCT imaging protocols at a similar level to the conventional CT images, when 3D surface models are required for the assessment of facial morphology.

Comparison of patient setup accuracy for optical surface-guided andX-ray-guided imaging with respect to the impact on intracranial stereotactic radiotherapy.

The objective of this work is to estimate the patient positioning accuracy of asurface-guided radiation therapy (SGRT) system using an optical surface scanner compared to an X‑ray-based imaging system (IGRT) with respect to their impact on intracranial stereotactic radiotherapy (SRT) and intracranial stereotactic radiosurgery (SRS). Patient positioning data, both acquired with SGRT and IGRT systems at the same linacs, serve as abasis for determination of positioning accuracy. Atotal of 35patients with two different open face masks (578 datasets) were positioned using X‑ray stereoscopic imaging and the patient position inside the open face mask was recorded using SGRT. The measurement accuracy of the SGRT system (in a"standard" and an SRS mode with higher resolution) was evaluated using both IGRT and SGRT patient positioning datasets taking into account the measurement errors of the X‑ray system. Based on these clinically measured datasets, the positioning accuracy was estimated using Monte Carlo (MC) simulations. The relevant evaluation criterion, as standard of practice in cranial SRT, was the 95th percentile. The interfractional measurement displacement vector of the SGRT system, σSGRT, in high resolution mode was estimated at 2.5 mm (68th percentile) and 5 mm (95th percentile). If the standard resolution was used, σSGRT increased by about 20%. The standard deviation of the axis-related σSGRT of the SGRT system ranged between 1.5 and 1.8 mm interfractionally and 0.5 and 1.0 mm intrafractionally. The magnitude of σSGRT is mainly due to the principle of patient surface scanning and not due to technical limitations or vendor-specific issues in software or hardware. Based on the resulting σSGRT, MC simulations served as ameasure for the positioning accuracy for non-coplanar couch rotations. If an SGRT system is used as the only patient positioning device in non-coplanar fields, interfractional positioning errors of up to 6 mm and intrafractional errors of up to 5mm cannot be ruled out. In contrast, MC simulations resulted in apositioning error of 1.6 mm (95th percentile) using the IGRT system. The cause of positioning errors in the SGRT system is mainly achange in the facial surface relative to adefined point in the brain. In order to achieve the necessary geometric accuracy in cranial stereotactic radiotherapy, use of an X‑ray-based IGRT system, especially when treating with non-coplanar couch angles, is highly recommended.

Evaluation of Daily Patient Position Accuracy and Calculation of Setup Errors with Skin Markers and Surface-Guided Radiotherapy (SGRT) in Breast Cancer

This study aims to compare the inter-fractional patient positioning errors between the use of skin markers and SGRT in patients receiving breast radiotherapy. It also includes calculating the inter- and intra-fractional PTV margins required for free breathing (FB) and deep inspiration breath-hold (DIBH) techniques due to setup uncertainties. The treatment data of a total of 2209 fractions from 80 patients who received whole breast or chest wall radiotherapy at an institution between March 2021 and December 2022 were retrospectively analyzed. In the first group of patients, the skin markers placed in the Computed Tomography (CT) scan with the FB technique were aligned and positioned with the room lasers in the Elekta Versa HD, and plan-specific shifts were made. The optical surface scanning procedure was applied to the second group of patients with the Sentinel™ system for FB or DIBH techniques in simulation. Patients were positioned for treatment by matching reference surface images with real-time images from the Catalyst™ HD surface imaging system. Positions of all patients were verified with kilovoltage or cone-beam CT imaging systems, and 3D shift vectors were recorded daily. To compare both setup methods, PTV margins including mean positioning shifts (MPS), the vector length of the shifts and setup errors were calculated from van Herk's formulas. The MPS of all patients using skin markers were 0.20±0.85 cm, 0.32±1.55 cm, and 0.18±0.44 cm in the vertical, longitudinal and lateral directions, respectively. Then, these values given above were found to be 0.12±0.15 cm, 0.06±0.17 cm, 0.07±0.23 cm for FB using Catalyst™ HD, and 0.34±0.30 cm, 0.29±0.26 cm, 0.23±0.30 cm for DIBH. In different setup techniques, no statistically significant difference was found between the 3D shift vectors in any direction with Wilcoxon signed-rank test (p>0.05). The mean standard deviation values in all directions were calculated as 1.22 cm and 0.61 cm, respectively, in patients using skin markers and SGRT. This study indicates a significant difference between the positioning shifts of patients positioned with skin markers and SGRT. The surface imaging system is an advantageous non-invasive method that increases setup accuracy and reproducibility in breast radiotherapy.

A consistent methodology for forensic photogrammetry scanning of human remains using a single handheld DSLR camera.

Close-range photogrammetry is an easy, fast, and cheap way to acquire 3D models of human remains of forensic importance.A carefully composed, tested, and systematic photographing procedure has a key role and can greatly increase the quality of photogrammetry models.A photogrammetry-based 3D-digitalization technique could be developed and adopted as part of the daily routine during autopsies.Photogrammetry-based 3D models are much quicker to acquire, look more photorealistic, and are almost as accurate as certain laser scanner-based models.

Comparative analysis of the trueness of linear measurements using direct and indirect scanning protocols compared to actual clinical measurements.

To assess the trueness of digital measurements using direct and indirect scanning approaches compared to the actual clinical measurements. The crown length, width, and width/length ratio were measured in 36 anterior maxillary teeth using three different methods. The first was clinically using a digital caliper, the second was by scanning the teeth using a digital scanner and the third was by making an impression of the teeth, constructing a stone cast in the lab, and scanning it to obtain digital measurements. Bland-Altman test and intraclass correlation were used to assess the data and make comparisons. Measurements taken using both approaches were highly reliable, with intraclass correlations ranging from 0.934 to 0.977 (p ≤ 0.000). Bland-Altman plot reflected a minimal mean difference between measurements especially in crown width measurements. Crown width/crown length measurement displayed the highest mean difference. Both direct and indirect optical surface scans showed similar high trueness in linear measurements of teeth. A higher discrepancy was detected in the crown width/length ratio. Digital dentistry is the new era in patient management. The use of conventional impression techniques and physical dental casts is associated with several disadvantages. Scanning dental casts to convert physical records into digital ones has multiple advantages. Optical surface scans (digital models) of the dentition are currently being more broadly used and advocated in the different dental disciplines including the construction of surgical guides for esthetic crown lengthening procedures. The trueness and reliability of linear measurements are of paramount importance to allow for proper fit and predictable outcomes. In this study, the trueness of these linear measurements obtained using direct and indirect methods was compared to the actual clinical measurements.

Cross-sectional assessment of body composition and detection of malnutrition risk in participants with low body mass index and eating disorders using 3D optical surface scans

BackgroundNew recommendations for the assessment of malnutrition and sarcopenia include body composition, specifically reduced muscle mass. Three-dimensional optical imaging (3DO) is a validated, accessible, and affordable alternative to dual X-ray absorptiometry (DXA). ObjectiveIdentify strengths and weaknesses of 3DO for identification of malnutrition in participants with low body mass index (BMI) and eating disorders. DesignParticipants were enrolled in the cross-sectional Shape Up! Adults and Kids studies of body shape, metabolic risk, and functional assessment and had BMI of <20 kg/m2 in adults or <85% of median BMI (mBMI) in children and adolescents. A subset was referred for eating disorders evaluation. Anthropometrics, scans, strength testing, and questionnaires were completed in clinical research centers. Lin’s Concordance Correlation Coefficient (CCC) assessed agreement between 3DO and DXA; multivariate linear regression analysis examined associations between weight history and body composition. ResultsAmong 95 participants, mean ± SD BMI was 18.3 ± 1.4 kg/m2 in adult women (N = 56), 19.0 ± 0.6 in men (N = 14), and 84.2% ± 4.1% mBMI in children (N = 25). Concordance was excellent for fat-free mass (FFM, CCC = 0.97) and strong for appendicular lean mass (ALM, CCC = 0.86) and fat mass (FM, CCC = 0.87). By DXA, 80% of adults met the low FFM index criterion for malnutrition, and 44% met low ALM for sarcopenia; 52% of children and adolescents were <−2 z-score for FM. 3DO identified 95% of these cases. In the subset, greater weight loss predicted lower FFM, FM, and ALM by both methods; a greater percentage of weight regained predicted a higher percentage of body fat. Conclusions3DO can accurately estimate body composition in participants with low BMI and identify criteria for malnutrition and sarcopenia. In a subset, 3DO detected changes in body composition expected with weight loss and regain secondary to eating disorders. These findings support the utility of 3DO for body composition assessment in patients with low BMI, including those with eating disorders.This trial was registered at clinicaltrials.gov as NCT03637855.

Comparative Analysis of 2D and 3D Metrics for Evaluation of Postoperative Outcomes Following Endoscopic Suturectomy for Sagittal Craniosynostosis.

To assess whether 3-dimensional (3D) volumetrics can be used to track and evaluate postoperative course of patients treated with endoscopic suturectomy for nonsyndromic sagittal synostosis, we compared changes in 2-dimensional (2D) measurements along with 3D volumetric correlates throughout the period of helmet therapy. Forty-six patients treated at our institution with endoscopic suturectomy for sagittal synostosis were retrospectively reviewed. Head circumference (HC), cephalic index (CI), and total cranial volumes (TCVs) were measured at 3 timepoints following surgery using optical surface scans obtained for helmet orthotics. All measurements showed significant differences between timepoints on the analysis of variance ( P <0.001). There was a significant correlation between CI and TCV (r=0.35, P =0.004) and between HC and TCV (r=0.81, P <0.001). The normalized rate of change over the course of treatment was significantly higher for TCV (36.7%) than for CI (8.8%) and HC (8.4%, P <0.001), with no difference between HC and CI. The authors conclude that 3D metrics were able to reliably follow the course of postoperative 2D metrics. There was a direct and linear correlation between HC and CI with TCV. Total cranial volumes showed the highest rate of sustained change at every timepoint. Although CI and HC plateau after the first measurement, TCV continues to adapt over the course of treatment. These results demonstrate the feasibility and value of volumetrics from 3D imaging to provide a more comprehensive evaluation of postoperative surgical outcomes than traditional 2D metrics without the ionizing radiation traditionally utilized for CT to obtain 3D metrics.

A STUDY ON CONVERGENCE MODELING OF CULTURAL ARTIFACT USING X-RAY COMPUTED TOMOGRAPHY AND THREE-DIMENSIONAL SCANNING TECHNOLOGIES

Abstract. Optical three-dimensional (3D) scanning technology is extensively used for digital recording and shape analysis of cultural heritage because it is simple to obtain precise surface shape and color information. In addition, X-ray computed tomography (X-ray CT) is used to record and analyze the internal shape of cultural heritage. However, while the 3D shape acquired by X-ray CT technology is excellent for visualizing the internal shape, expressing the high resolution of the surface shape is difficult. If the benefits of each technology are used to digitize the inside and outside of cultural heritage, the results of surface shape recording based on 3D scanning can be advanced, and various stereoscopic analysis can be performed. Therefore, an optimization modeling process that combines X-ray CT and optical surface scanning is required to record both internal and external shapes of cultural heritage. In this study, optimization modeling methodology was applied to cultural heritage by combining X-ray CT technology and optical 3D scanning technology. Based on the models obtained through both technologies, a mesh-based optimization convergence modeling methodology considering internal and external surface shapes and color is organized. Furthermore, because the X-ray CT data has a characteristic of a voxel base, it is determined that additional convergence methods, including internal voxel data, are required, and a voxel-based optimization model process is established concurrently. Following that, two convergence modeling methods were applied to each of the deer-shaped horn cup artifacts that had an interior shape. As a result, the 3D convergence model creation and mapping optimization process, which can reveal important internal and external information about artifacts such as surface color, fine shape, and internal structure, can be improved. This 3D convergence modeling methodology was able to supplement the two technologies while preserving the benefits of optical 3D scanning and X-ray CT technology. This is thought to contribute to the expansion of the digital recording process from a single technology to multiple technologies. The X-ray CT-based convergence modeling pipeline is expected to be an opportunity in promoting the revitalization of X-ray CT technology in the cultural heritage field because it can be used for a wide range of purposes such as shape analysis, preservation status evaluation, monitoring, restoration, and reproduction.

Temporally continuous thermofluidic–thermomechanical modeling framework for metal additive manufacturing

Additive manufacturing (AM) is known to generate large magnitudes of residual stresses (RS) within builds due to steep and localized thermal gradients. In the current state of commercial AM technology, manufacturers generally perform heat treatments in effort to reduce the generated RS and its detrimental effects on part distortion and in-service failure. Computational models that effectively simulate the deposition process can provide valuable insights to improve RS distributions. Accordingly, it is common to employ Computational fluid dynamics (CFD) models or finite element (FE) models. While CFD can predict geometric and thermal-fluid behavior, it cannot predict the structural response (e.g., stress–strain) behavior. On the other hand, an FE model can predict mechanical behavior, but it lacks the ability to predict geometric and fluid behavior. Thus, an effectively integrated thermofluidic–thermomechanical modeling framework that exploits the benefits of both techniques while avoiding their respective limitations can offer valuable predictive capability for AM processes. In contrast to previously published efforts, the work herein describes a one-way coupled CFD-FEA framework that abandons major simplifying assumptions, such as geometric steady-state conditions, the absence of material plasticity, and the lack of detailed RS evolution/accumulation during deposition, as well as insufficient validation of results. The presented framework is demonstrated for a directed energy deposition (DED) process, and experiments are performed to validate the predicted geometry and RS profile. Both single- and double-layer stainless steel 316L builds are considered. Geometric data is acquired via 3D optical surface scans and X-ray micro-computed tomography, and residual stress is measured using neutron diffraction (ND). Comparisons between the simulations and measurements reveal that the described CFD-FEA framework is effective in capturing the coupled thermomechanical and thermofluidic behaviors of the DED process. The methodology presented is extensible to other metal AM processes, including power bed fusion and wire-feed-based AM.

Accuracy of implant placement using CAD-CAM tooth-supported surgical guides for an auricular prosthesis in vitro.

To evaluate the accuracy of tooth-supported surgical guides used to place implants in auricular prostheses. The accuracy (trueness and precision) of the implant positions was evaluated, and the difference between the surgical guide with and without retention of the external auditory canal (EAC) was compared. This study simulated implant placement in vitro for the treatment of right auricle malformation. Surgical guides and other casts were fabricated using additive manufacturing technology. The casts were divided into 2 groups according to the surgical guide, with 10 bone blocks in each group (with or without the EAC plug (Guides 1 and 2)). Three implant positions (Implants 1-3) were prepared for each bone block using surgical guides. Implant positions were registered using light-body silicone impressions combined with optical surface scans to measure the coronal, apical, depth, and angular deviations. Four deviations of trueness and precision were reported as the mean±standard deviation, which was analyzed by Student's t-test. Each group of 10 bone blocks with 30 implant positions was successfully prepared and digitally reproduced as implants. The accuracies of implant position with surgical guides were acceptable when compared with the preoperatively planned implant positions. Compared with the Guide 2 group, there was a significant difference in the apical, depth, and angular deviations of Guide 1 group in terms of precision (p=0.001). There was a significant difference in the depth deviation of Implant 1 (p=0.028) and apical deviation of Implant 2 (p<0.001) compared two groups in terms of trueness. In terms of precision, there was a significant difference in the coronal (p=0.002), apical (p=0.001), and depth (p<0.001) deviation of Implant 1; apical (p=0.036) and angular (p<0.001) deviation of Implant 2 also existed significant difference; the coronal deviation of Implant 3 (p=0.018) also existed significant difference. Moreover, the group with the EAC plug showed lower deviation in precision and a smaller volume in the 95% confidence ellipsoid. Both types of tooth-supported surgical guides can provide acceptable accuracy. A surgical guide with an EAC plug was considered to be more precise.

Synthetic cranial MRI from 3D optical surface scans using deep learning for radiation therapy treatment planning

BackgroundOptical scanning technologies are increasingly being utilised to supplement treatment workflows in radiation oncology, such as surface-guided radiotherapy or 3D printing custom bolus. One limitation of optical scanning devices is the absence of internal anatomical information of the patient being scanned. As a result, conventional radiation therapy treatment planning using this imaging modality is not feasible. Deep learning is useful for automating various manual tasks in radiation oncology, most notably, organ segmentation and treatment planning. Deep learning models have also been used to transform MRI datasets into synthetic CT datasets, facilitating the development of MRI-only radiation therapy planning.AimsTo train a pix2pix generative adversarial network to transform 3D optical scan data into estimated MRI datasets for a given patient to provide additional anatomical data for a select few radiation therapy treatment sites. The proposed network may provide useful anatomical information for treatment planning of surface mould brachytherapy, total body irradiation, and total skin electron therapy, for example, without delivering any imaging dose.MethodsA 2D pix2pix GAN was trained on 15,000 axial MRI slices of healthy adult brains paired with corresponding external mask slices. The model was validated on a further 5000 previously unseen external mask slices. The predictions were compared with the “ground-truth” MRI slices using the multi-scale structural similarity index (MSSI) metric. A certified neuro-radiologist was subsequently consulted to provide an independent review of the model’s performance in terms of anatomical accuracy and consistency. The network was then applied to a 3D photogrammetry scan of a test subject to demonstrate the feasibility of this novel technique.ResultsThe trained pix2pix network predicted MRI slices with a mean MSSI of 0.831 ± 0.057 for the 5000 validation images indicating that it is possible to estimate a significant proportion of a patient’s gross cranial anatomy from a patient’s exterior contour. When independently reviewed by a certified neuro-radiologist, the model’s performance was described as “quite amazing, but there are limitations in the regions where there is wide variation within the normal population.” When the trained network was applied to a 3D model of a human subject acquired using optical photogrammetry, the network could estimate the corresponding MRI volume for that subject with good qualitative accuracy. However, a ground-truth MRI baseline was not available for quantitative comparison.ConclusionsA deep learning model was developed, to transform 3D optical scan data of a patient into an estimated MRI volume, potentially increasing the usefulness of optical scanning in radiation therapy planning. This work has demonstrated that much of the human cranial anatomy can be predicted from the external shape of the head and may provide an additional source of valuable imaging data. Further research is required to investigate the feasibility of this approach for use in a clinical setting and further improve the model’s accuracy.

High-performance integrated manufacturing of a 3Y-TZP ceramic crown through viscoelastic paste-based vat photopolymerization with a conformal contactless support

Ceramic vat photopolymerization has been one of the promising three-dimensional printing technologies for personalized zirconia crown with high dimensional accuracy and surface topography. However, insufficient material stability and complex procedure about auxiliary supports limit the application based on low viscosity slurry. In this work, we developed a photocurable ceramic paste, in which the high static viscosity and high yield stress characteristics allowed it to exhibit sufficient anti-settling and self-supporting capabilities. The rheological characteristics of the as prepared paste were measured by stress-controlled rheometer, and conformal contactless support was designed including top conformal structure without contact with the crown and appropriate empty layer. The 3D precision of crown was evaluated by laser scanning confocal microscope and optical surface scanner. In addition, mechanical properties and biocompatibility of sintered samples were systematically evaluated. The results demonstrated that the yield stress of the ceramic paste approached around 600 Pa, and integrate morphology at the bottom of the crown with the contactless supported zone was observed. 3D deviation between the printed crown scan data and the reference model was reduced within the range of 40–70 µm. Finally, the flexural strength and fracture toughness of the sintered zirconia ceramics reached 1117 MPa and 7.76 MPa⋅m 1/2 , respectively, as well as good biocompatibility by the lack of cytotoxicity and hemolytic reaction. The results indicate an important practical significance for the development of vat photopolymerization printing technology of viscoelastic paste and conformal contactless support strategy to realize the integrated manufacturing of ceramic crowns.

Surface guided 3DCRT in deep-inspiration breath-hold for left sided breast cancer radiotherapy: implementation and first clinical experience in Iran.

The aim of the study is to evaluate the overall accuracy of the surface-guided radiotherapy (SGRT) workflow through a comprehensive commissioning and quality assurance procedures and assess the potential benefits of deep-inspiration breath-hold (DIBH) radiotherapy as a cardiac and lung dose reduction approach for left-sided breast cancer irradiation. Accuracy and reproducibility of the optical surface scanner used for DIBH treatment were evaluated using different phantoms. Patient positioning accuracy and reproducibility of DIBH treatment were evaluated. Twenty patients were studied for treatment plan quality in target dose coverage and healthy organ sparing for the two different treatment techniques. Reproducibility tests for the surface scanner showed good stability within 1 mm in all directions. The maximum position variation between applied shifts on the couch and the scanner measured offsets is 1 mm in all directions. The clinical study of 200 fractions showed good agreement between the surface scanner and portal imaging with the isocenter position deviation of less than 3 mm in each lateral, longitudinal, and vertical direction. The standard deviation of the DIBH level showed a value of < 2 mm during all evaluated DIBHs. Compared to the free breathing (FB) technique, DIBH showed significant reduction of 48% for heart mean dose, 43% for heart V25, and 20% for ipsilateral lung V20. Surface-guided radiotherapy can be regarded as an accurate tool for patient positioning and monitoring in breast radiotherapy. DIBH treatment are considered to be effective techniques in heart and ipsilateral lung dose reductions for left breast radiotherapy.

Structural, vibrational spectroscopy, molecular docking, DFT studies and antibacterial activity of (E)-N1-(3-chlorobenzylidene)benzene-1,4-diamine

In this work, (E)-N1-(3-chlorobenzylidene)benzene-1,4-diamine (CBD) compound was synthesized with good yield. The spectral studies were recorded by FT-IR, FT-Raman, NMR and UV-Vis to determine structural parameters. The geometrical parameters were optimized using DFT calculations at 6-311++G(d,p) basis set. The calculated structural parameters of the molecule were in line with the experimental data. The molecular orbitals of the compound were investigated through highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) analysis. The hyper conjugative interaction energy E(2) along with donor, acceptor electron densities (EDs) were determined by natural bond orbital (NBO) analysis. The molecular electrostatic potential (MEP), mulliken atomic charges, non-linear optical (NLO) properties and potential energy surface (PES) scan were also calculated. The 1H and 13C NMR chemical shifts calculated using Gauge invariant atomic orbital (GIAO) method were compared with the experimental NMR chemical shifts. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were carried out to characterise the thermal behaviour and stability of CBD molecule. In addition, PreADMET tool was also used to estimate ADME and Toxicity of CBD compound. The compound screened against four pathogens two gram positive and two gram negative had shown good anti-bacterial behaviour. The molecular docking studies executed against anti-bacterial target topoisomerase DNA gyrase enzyme (2XCT) emphasized good binding behaviour over the standard drug. Communicated by Ramaswamy H. Sarma

Predicting Aesthetic Outcome of the Nuss Procedure in Patients with Pectus Excavatum

Patients suffering from pectus excavatum often experience psychosocial distress due to perceived anomalies in their physical appearance. The ability to visually inform patients about their expected aesthetic outcome after surgical correction is still lacking. This study aims to develop an automatic, patient-specific model to predict aesthetic outcome after the Nuss procedure. Patients prospectively received preoperative and postoperative 3-dimensional optical surface scanning of their chest during the Nuss procedure. A prediction model was composed based on nonlinear least squares data-fitting, regression methods and a 2-dimensional Gaussian function with adjustable amplitude, variance, rotation, skewness, and kurtosis components. Morphological features of pectus excavatum were extracted from preoperative images using a previously developed surface analysis tool to generate a patient-specific model. Prediction accuracy was evaluated through cross-validation, utilizing the mean root squared deviation and maximum positive and negative deviations as performance measures. The prediction model was evaluated on 30 (90% male) prospectively imaged patients. The model achieved an average root mean squared deviation of 6.3 ± 2.0 mm, with average maximum positive and negative deviations of 12.7 ± 6.1 and -10.2 ± 5.7 mm, respectively, between the predicted and actual postoperative aesthetic result. Our developed 2-dimensional Gaussian model based on 3-dimensional optical surface images is a clinically promising tool to predict postsurgical aesthetic outcome in patients with pectus excavatum. Prediction of the aesthetic outcome after the Nuss procedure potentially improves information provision and expectation management among patients. Further research should assess whether increasing the sample size may reduce deviations and improve performance.

Biological activities of Ethanolic Extract Produced by Cucurbita pepo plant.

Antibacterial and antioxidant effects of alcoholic extract for the Cucurbita pepo plant were studied. Properties optical (UV-visible spectrophotometer ) and morphological surface(scanning electron microscopy ) detection of the alcoholic extract was done, and the antibacterial activity was investigated against pathogenic microbes (E.coli, Staphylococcus aureus). Results showed the highest effect for crud extract in the growth of E.coli by the zone of inhibition diameter reached (16.33±0.58 ), followed by Staph. Aureus by the diameter of the inhibition zone reached (12.33±2.30mm). The results indicate that the plant C. pepo can be considered a valuable source of effective antioxidant agents at a 0.8 µg/ml concentration. Keywords. Cucurbita pepo plant: Alcoholic extract: Antioxidant: Antibacterial Activity

Stator Blades Manufacturing Geometrical Variability in Axial Compressors and Impact on the Aeroelastic Excitation Forces

AbstractThe manufacturing geometrical variability is a source of uncertainty, which cannot be avoided in the realization of machinery components. Deviations of a part geometry from its nominal design are inevitably present due to the manufacturing process. In the case of the aeroelastic forced response problem within axial compressors, these uncertainties may affect the vibration characteristics. For this reason, the impact of geometrical uncertainties due to the manufacturing process onto the modal forcing of axial compressor blades is investigated in this study. The research focuses on the vibrational behavior of an axial compressor rotor blisk. In particular, the amplitude of the forces acting as a source of excitation on the vibrating blades is studied. The geometrical variability of the upstream stator is investigated as input uncertainty. The variability is modeled starting from a series of optical surface scans. A stochastic model is created to represent the measured manufacturing geometrical deviations from the nominal model. A data reduction methodology is proposed in order to represent the uncertainty with a minimal set of variables. The manufacturing geometrical variability model allows to represent the input uncertainty and probabilistically evaluate its impact on the aeroelastic problem. An uncertainty quantification is performed in order to evaluate the resulting variability on the modal forcing acting on the vibrating rotor blades. Of particular interest is the possible rise of low engine orders due to the mistuned flow field along the annulus. A reconstruction algorithm allows the representation of the variability during one rotor revolution. The uncertainty on low harmonics of the modal rotor forcing can be therefore identified and quantified.

Geometrical analysis for motion monitoring of rigid bodies with optical surface scanning in radiation oncology.

Surface guided radiotherapy can be used to improve patient setup and for accurate intra-fraction motion monitoring in correspondence to the isocenter. For a clinical relevant motion analysis the actual displacement of the entire clinical target volume (CTV) is necessary. Therefore, the aim of this study was to develop a novel assessment method for intra-fraction motion for rigid body structures based on motion data and a geometrical analysis. A threshold value on the volume coverage (VC(t)) of the CTV by the planning target volume (PTV) was proposed as online motion monitoring method. Moreover, offline analysis was performed by using heat maps and by calculating VCx, the volume coverage for at least x% of treatment time. The method was applied retrospectively to patient treatment data for whole brain radiation treatment without a thermoplastic mask. In 132 out of 142 fractions in total the proportion of the CTV that was inside the PTV for at least 99% of the time (VC99) was more than 95%, for a CTV-to-PTV margin of 5mm. The source-voxel heat map showed which part of the CTV had a reduced coverage and the target heat map showed the movement of the CTV. Instead of using an action threshold on the movements of the isocenter, a threshold on the VC(t) of the CTV by the PTV was proposed. The heat maps and resulting values of VCx can be used to adapt the VC(t) threshold or the CTV-to-PTV margin for subsequent fractions.

A Two-stage Registration Method for Dental Volumetric Data and Mesh Data

Dental computed tomography (CT) images and optical surface scan data are widely used in dental computer-aided design systems. Registration is essential if they are used in software systems. Existing automatic registration methods are either time-consuming or rough, and interactive registration methods are experience-dependent and tedious because of a great deal of purely manual interactions. For overcoming these disadvantages, a two-stage registration method is proposed. In the rough registration stage, the rough translation and rotation matrices are obtained by applying unit quaternion based method on the points interactively selected from the two types of data. In the precise registration stage, the stridden sampling is used to reduce computational complexity and the proposed registration algorithm with scale transformation is used for precise registration. The proposed method offers a good trade-off between precision and time cost. The experimental results demonstrate that the proposed method provides faster convergence and smaller registration errors than existing methods.