Anthropomorphic Model Research Articles

A continuous model of a standing human body in vertical vibration

This paper develops a continuous standing human body model in the vertical vibration based on an anthropomorphic model, two measured natural frequencies of a biomechanics model, and structural dynamics methods. The mass distribution of a standing body is formed using the mass distribution of fifteen body segments in the anthropomorphic model. The axial stiffness of the model is determined based on the best matching to the two natural frequencies of the biomechanics model which were obtained using shaking table tests. Four similar models are assessed using finite element parametric analysis. The best of the four models has seven uniform mass segments with two stiffnesses and the same fundamental natural frequency as that of the biomechanics model, but its second natural frequency is 10% higher. The mode shapes of the continuous model are presented to demonstrate the relative magnitude of vibration throughout the height of the body. Finally the modal mass and stiffness of the continuous model are evaluated, which are related to some simple discrete models.

Incorporation of Ultrasonic Prior Information for Improving Quantitative Microwave Imaging of Breast

Structural information derived via ultrasound is utilized as prior information for quantitative microwave imaging. The structural information is extracted from ray-based ultrasound reconstructions using a K-means clustering algorithm and consists of three tissue regions (skin, adipose, and fibroglandular). Tissue-specific complex permittivity values are assigned to each region (i.e., the complex permittivity is homogeneous over each region). The regions are then incorporated as an inhomogeneous numerical background in a quantitative microwave imaging algorithm (contrast source inversion). This new approach is assessed using synthetic data obtained from several anthropomorphic breast models of various densities derived from magnetic resonance imaging breast images, all containing tumors. Imaging results are quantitatively evaluated based on the algorithm's ability to detect the tumors. The performance is tested with four different variations of the prior information: two variations of the structural information and two of the assigned permittivity values. The resulting ultrasound-microwave multimodality imaging approach substantially improves the fidelity and accuracy of the reconstructed internal structures relative to previous studies that used radar-based microwave techniques to extract the internal structural information. An improvement in the sensitivity of the imaging algorithm to malignant tissue is also observed.

Digital Human and Robot Simulation in Automotive Assembly using Siemens Process Simulate: A Feasibility Study

Abstract The global trend toward customization in the automotive sector has led to significant increase in the variability of components available to the assembly process. The increase in product variability directly impacts the complexity of the manufacturing process and consequently increases the possibility for human-generated error. Several solutions have been offered to reduce the potential risk of error in complex assembly processes which can be generalized as cognitive-based or physical-based assistive methods. Creating a digital twin of the process, both the human and machine elements, is a preliminary requirement before deploying such solutions in a real-world manufacturing environment. The digital twin simulation provides a platform for testing a variety of solutions and what-if scenarios to improve planning and decision making. While there exist commercially available products of human digital twin modeling, these do not provide a proper platform for human – machine interaction modeling. In the context of this work, machine is defined as an industrial robot with an objective of investigating the feasibility of deploying a smart collaborative robotic solution to provide physical assistance to the human worker in a cumbersome manufacturing process. To do so, an overhead assembly operation from a real-world vehicle assembly plant is identified, and a digital twin of human model is created in Siemens Tecnomatix suite. The study starts with the simulation of various human anthropomorphic models to discover the limitations in performing the assembly tasks based on gender, weight and height. Furthermore, a digital twin of a mobile robot designed to provide physical assistance to the human to perform the assembly operation is introduced. The results are evaluated in terms of process time, joint ergonomic impact and reveal some current limitations of combined digital twin modeling of humans and robots collaborating.

Modelling a quad-bike rollover mechanism when traversing an asymmetric bump

Experimental testing of a quad bike traversing a bump placed in-line with one of the vehicle’s wheel tracks showed that a passive rider could be displaced across the quad-bike seat resulting in the vehicle’s sudden unintentional steering. It was hypothesised that this ‘bump’ mechanism could result in a rollover. To determine whether such a bump mechanism can precipitate a rollover and under what conditions it occurs, an earlier developed quad bike FE model combined with a seated Anthropomorphic Test Device FE model was validated against experimental tests of the quad bike traversing a semi-cylindrical bump. A sensitivity analysis was then carried out varying the initial conditions of ground friction and approach angle on flat terrain. The FE simulations show that the bump mechanism, for a particular set of friction values and approach angle, resulted in a rollover. The identified bump-induced rollover mechanism could help explain some of the rollover-associated quad bike crashes on Australian farms where it was known that a fatality occurred as a result of rollover which happened due to traversing a bump from Coronial investigations carried out by the authors.

Three-dimensional kinematic corridors of the head, spine, and pelvis for small female driver seat occupants in near- and far-side oblique frontal impacts

Objectives: Analyses of recent automotive accident data indicate an increased risk of injury for small female occupants compared to males in similar accidents. Females have been shown to be more susceptible to spinal injuries than males. To protect this more vulnerable population, advanced anthropomorphic test devices (ATDs) and computer human body models are being developed and require biofidelity curves for validation. The aim of this study is to generate female-specific 3D kinematic corridors in near- and far-side oblique frontal impacts for the head, spine, and pelvis.Methods: Eight specimens were procured and prescreened for mass, stature, and quantitative computed tomography bone mineral density and preexisting injuries to minimize biologic variability. Sets of 4 noncolinear retroreflective targets were placed on the back of the head; dorsal spine at T1, T8, and L2; and posterior sacrum. Instrumented computed tomography scans were obtained to measure the orientation and position of the markers relative to anatomic fiducials. The specimens were placed on a buck representative of a generic automotive driver’s seat environment designed to minimize lower-extremity and pelvic motion. The buck was oriented such that the buck centerline was seated 30° from the impact vector in either a near- or far-side oblique frontal configuration. Preposition of the occupant was specified to the 50th percentile male H-point location, thigh and tibial angles, and torso angle. Impact was delivered via a servo-acceleration sled to the base of the buck with a 30 km/h 9 g trapezoidal pulse. Occupants were restrained by a standard 3-point belt that had a custom load-limiter device set to 2 kN at the D-ring side of the shoulder belt. Target motion was recorded at 1 kHz using a 3D optical motion capture system. Anatomic motion of the head, spine, and pelvis was calculated relative to the seat, and the average response was determined from 4 near-side and 4 far-side tests. The borders of the corridor were determined by calculating a standard deviational ellipse in the x, y, and z planes at each time step.Results: Plots of the biofidelity corridors for near- and far-side tests are shown in planes parallel to the seat from the lateral, rear, and overhead directions. Averaged peak excursions in the fore/aft and lateral directions are compared for the near- and far-side corridors. Near-side female and male tests are similarly compared.Conclusions: In general, average peak excursions were greater in the far-side configuration than in the near-side configuration. Peak excursion results compared well with similar tests conducted on male postmortem human subjects (PMHS). The kinematic corridors developed in the current study serve as a set of biofidelity corridors for the development of current and future physical and computational surrogates.

Anthropomorphic breast model repository for research and development of microwave breast imaging technologies

A repository of anthropomorphic numerical breast models is made available for the scientific community to support research and development of microwave imaging technologies for diagnostic and therapeutic applications. These models are constructed from magnetic resonance imaging (MRI) scans acquired at our university hospital. Our 3D breast modelling method is used to translate the MRI scans into 3D models representing the geometry and microwave-frequency properties of tissues in the breast. The reconstructed models demonstrate anatomical realism, reconfigurable complexity, and flexibility to adapt to simulations of various microwave imaging techniques and prototype systems. With these models, realistic and rigorous test scenarios can be defined in simulations to support feasibility analysis, performance verification and design improvements of developing microwave imaging techniques, prior to testing on experimental systems. A repository of breast models is created which includes breasts of varying classification – fatty, scattered, heterogeneous, and dense. In addition, the models include brief documentation to facilitate researchers in selecting a model by matching its features with their requirements.

Development of a three-dimensional body shape model of young children for child restraint design

The design of child restraints is guided in part by anthropometric data describing the distributions of body dimensions of children. However, three-dimensional body shape data have not been available for children younger than three years of age. This study presents body shape models for children weighing 9–23 kg in a seated posture relevant to child restraint design. A laboratory study collected surface geometry data of 67 children, ages 12–58 months. Novel template fitting methods were employed to obtain homologous meshes and to standardize the posture. Principal component analysis and regression were used to develop a statistical body shape model (SBSM). The SBSM was exercised to create 18 manikins representing children aged 1–3 years, with varying size and shape. These manikins will be useful for assessing child accommodation in restraints. The SBSM can also provide guidance for the development of anthropomorphic test devices and computational models of child occupants.

CNN as model observer in a liver lesion detection task for x-ray computed tomography: A phantom study.

The purpose of this study was the evaluation of anthropomorphic model observers trained with neural networks for the prediction of a human observer's performance. To simulate liver lesions, a phantom with contrast targets (acrylic spheres, varying diameters, +30HU) was repeatedly scanned on a computed tomography scanner. Image data labeled with confidence ratings assessed in a reader study for a detection task of liver lesions were used to build several anthropomorphic model observers. Models were trained with images reconstructed with iterative reconstruction and evaluated with images reconstructed with filtered backprojection. A neural network, based on softmax regression (SR-MO), and convolutional neural networks (CNN-MO) were used to predict the performance of a human observer and compared to a channelized Hotelling observer [with Gabor channels and internal channel noise (CHOi)]. Model observers were evaluated by a receiver operating characteristic curve analysis and compared to the results in the reader study. Two strategies were used to train the SR-MO and CNN-MO: A) building a separate model for each lesion size; B) building one model that was applied to lesions of all sizes. All tested model observers and the human observer were highly correlated at each lesion size and dose level. With strategy A, Pearson's product-moment correlation coefficients r were 0.926 (95% confidence interval (CI): 0.679-0.985) for SR-MO and 0.979 (95% CI: 0.902-0.996) for CNN-MO. With strategy B, r was 0.860 (95% CI: 0.454-0.970) for SR-MO and 0.918 (95% CI: 0.651-0.983) for CNN-MO. For CHOi, r was 0.945 (95% CI: 0.755-0.989). With strategy A, mean absolute percentage differences (MAPD) between the model observers and the human observer were 3.7% for SR-MO and 1.2% for CNN-MO. With strategy B, MAPD were 3.7% for SR-MO and 3.0% for CNN-MO. For the CHOi the MAPD was 2.2%. Convolutional neural network model observers can accurately predict the performance of a human observer for all lesion sizes and dose levels in the evaluated signal detection task.

Modeling Tissue Heating From Exposure to Radiofrequency Energy and Relevance of Tissue Heating to Exposure Limits: Heating Factor.

This review/commentary addresses recent thermal and electromagnetic modeling studies that use image-based anthropomorphic human models to establish the local absorption of radiofrequency energy and the resulting increase in temperature in the body. The frequency range of present interest is from 100 MHz through the transition frequency (where the basic restrictions in exposure guidelines change from specific absorption rate to incident power density, which occurs at 3-10 GHz depending on the guideline). Several detailed thermal modeling studies are reviewed to compare a recently introduced dosimetric quantity, the heating factor, across different exposure conditions as related to the peak temperature rise in tissue that would be permitted by limits for local body exposure. The present review suggests that the heating factor is a robust quantity that is useful for normalizing exposures across different simulation models. Limitations include lack of information about the location in the body where peak absorption and peak temperature increases occur in each exposure scenario, which are needed for careful assessment of potential hazards. To the limited extent that comparisons are possible, the thermal model (which is based on Pennes' bioheat equation) agrees reasonably well with experimental data, notwithstanding the lack of theoretical rigor of the model and uncertainties in the model parameters. In particular, the blood flow parameter is both variable with physiological condition and largely determines the steady state temperature rise. We suggest an approach to define exposure limits above and below the transition frequency (the frequency at which the basic restriction changes from specific absorption rate to incident power density) to provide consistent levels of protection against thermal hazards. More research is needed to better validate the model and to improve thermal dosimetry in general. While modeling studies have considered the effects of variation in thickness of tissue layers, the effects of normal physiological variation in tissue blood flow have been relatively unexplored.

Finite-element analysis of microwave scattering from a three-dimensional human head model for brain stroke detection.

In this paper, a detailed analysis of microwave (MW) scattering from a three-dimensional (3D) anthropomorphic human head model is presented. It is the first time that the finite-element method (FEM) has been deployed to study the MW scattering phenomenon of a 3D realistic head model for brain stroke detection. A major contribution of this paper is to add anatomically more realistic details to the human head model compared with the literature available to date. Using the MRI database, a 3D numerical head model was developed and segmented into 21 different types through a novel tissue-mapping scheme and a mixed-model approach. The heterogeneous and frequency-dispersive dielectric properties were assigned to brain tissues using the same mapping technique. To mimic the simulation set-up, an eight-elements antenna array around the head model was designed using dipole antennae. Two types of brain stroke (haemorrhagic and ischaemic) at various locations inside the head model were then analysed for possible detection and classification. The transmitted and backscattered signals were calculated by finding out the solution of the Helmholtz wave equation in the frequency domain using the FEM. FE mesh convergence analysis for electric field values and comparison between different types of iterative solver were also performed to obtain error-free results in minimal computational time. At the end, specific absorption rate analysis was conducted to examine the ionization effects of MW signals to a 3D human head model. Through computer simulations, it is foreseen that MW imaging may efficiently be exploited to locate and differentiate two types of brain stroke by detecting abnormal tissues’ dielectric properties. A significant contrast between electric field values of the normal and stroke-affected brain tissues was observed at the stroke location. This is a step towards generating MW scattering information for the development of an efficient image reconstruction algorithm.

A projection image database to investigate factors affecting image quality in weight-based dosing: application to pediatric renal SPECT

Balancing the tradeoff between radiation dose, acquisition duration and diagnostic image quality is essential for medical imaging modalities involving ionizing radiation. Lower administered activities to the patient can reduce absorbed dose, but can result in reduced diagnostic image quality or require longer acquisition durations. In pediatric nuclear medicine, it is desirable to use the lowest amount of administered radiopharmaceutical activity and the shortest acquisition duration that gives sufficient image quality for clinical diagnosis. However, diagnostic image quality is a complex function of patient factors including body morphometry. In this study, we present a digital population of 90 computational anatomic phantoms that model realistic variations in body morphometry and internal anatomy. These phantoms were used to generate a large database of projection images modeling pediatric SPECT imaging using a 99mTc-DMSA tracer. We used an analytic projection code that models attenuation, spatially varying collimator-detector response, and object-dependent scatter to generate the projections. The projections for each organ were generated separately and can be subsequently scaled by parameters extracted from a pharmacokinetics model to simulate realistic tracer biodistribution, including variations in uptake, inside each relevant organ or tissue structure for a given tracer. Noise-free projection images can be obtained by summing these individual organ projections and scaling by the system sensitivity and acquisition duration. We applied this database in the context of 99mTc-DMSA renal SPECT, the most common nuclear medicine imaging procedure in pediatric patients. Organ uptake fractions based on literature values and patient studies were used. Patient SPECT images were used to verify that the sum of counts in the simulated projection images was clinically realistic. For each phantom, 384 uptake realizations, modeling random variations in the uptakes of organs of interest, were generated, producing 34 560 noise-free projection datasets (384 uptake realizations times 90 phantoms). Noisy images modeling various count levels (corresponding to different products of acquisition duration and administered activity) were generated by appropriately scaling these images and simulating Poisson noise. Acquisition duration was fixed; six count levels were simulated corresponding to projection images acquired using 25%, 50%, 75%, 100%, 125%, and 150% of the original weight-based administrated activity as computed using the North American Guidelines (Gelfand et al 2011 J. Nucl. Med. 52 318–22). Combined, a total number of 207 360 noisy projection images were generated, creating a realistic projection database for use in renal pediatric SPECT imaging research. The phantoms and projection datasets were used to calculate three surrogate indices for factors affecting image quality: renal count density, average radius of rotation, and scatter-to-primary ratio. Differences in these indices were seen across the phantoms for dosing based on current guidelines, and especially for the phantom modeling the newborn. We also performed an image quality study using an anthropomorphic model observer that demonstrates that the weight-based dose scaling does not equalize image quality as measured by the area under the receiver-operating characteristics curve. These studies suggest that a dosing procedure beyond weight-based scaling of administered activities is required to equalize image quality in pediatric renal SPECT.

Selected parameter’s simulation research in a hydrostatic drive system for anthropomorphic manipulators used in transportation

The article compares anthropomorphic and industrial manipulators. The basic differences between these constructions are indicated, resulting both from the control method as well as the kinematic structure. Presented the method of developing the kinematic structure of the anthropomorphic manipulator as a construction similar to the human upper limb. An anthropomorphic manipulator model was developed based on accepted assemblies concerning a significant increase in human working capacity in the context of reloading and transport work. Simulation studies were carried out on the manipulator model developed in the aspect of determining selected hydro-static drive system parameters.

Application of a Compact Electromagnetic Bandgap Array in a Phone Case for Suppression of Mobile Phone Radiation Exposure

In this paper, a mobile phone case incorporating electromagnetic bandgap (EBG) material is studied to intercept electromagnetic (EM) waves from the phone and reduce the specific absorption rate (SAR). A loop antenna for the personal communications service 1900-MHz band is considered. In addition, three different mobile phone cases associating EBG structures with optimized positions are used to improve SAR reduction. Furthermore, antenna performance with an EBG structure is investigated with a full-body EM simulation program, SEMCAD X, and an individual performance analysis of each EBG structure was carried out by using Ansoft HFSS. A human head phantom to replicate the specific anthropomorphic mannequin model was used for measurements. From simulation and measurement, it is found that placing an EBG structure in a phone case can improve antenna gain and reduce SAR. Moreover, a maximum gain increment of 19% and an SAR reduction of 24% were found. This paper reveals the future applications of EBG structures for SAR reduction in mobile phones.

MP26-09 NOVEL TRACKED FOLEY CATHETER FOR MOTION COMPENSATION DURING IMAGE GUIDED PROSTATE PROCEDURES

You have accessJournal of UrologySurgical Technology & Simulation: Instrumentation & Technology I1 Apr 2018MP26-09 NOVEL TRACKED FOLEY CATHETER FOR MOTION COMPENSATION DURING IMAGE GUIDED PROSTATE PROCEDURES Graham R. Hale, Sheng Xu, Samuel A. Gold, Kareem N. Rayn, Jonathan B. Bloom, Sherif Mehralivand, Neil Glossop, Baris Turkbey, Peter A. Pinto, and Brad Wood Graham R. HaleGraham R. Hale More articles by this author , Sheng XuSheng Xu More articles by this author , Samuel A. GoldSamuel A. Gold More articles by this author , Kareem N. RaynKareem N. Rayn More articles by this author , Jonathan B. BloomJonathan B. Bloom More articles by this author , Sherif MehralivandSherif Mehralivand More articles by this author , Neil GlossopNeil Glossop More articles by this author , Baris TurkbeyBaris Turkbey More articles by this author , Peter A. PintoPeter A. Pinto More articles by this author , and Brad WoodBrad Wood More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.867AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The ″Tracked Foley″ (TF) is a new technology that uses previously cached MRI data to help orient operators to prostate anatomy and surrounding structures during procedures. Sensors within the TF communicate with an MRI/US fusion system to maintain proper registration (alignment/matching) between MRI and surgical anatomy location and orientation in real time. Although speculative, this feature may augment the da Vinci® robot or focal therapy. We sought to evaluate if the TF could maintain accurate registration after organ and patient motion using custom TF/MRI fusion software. METHODS Study was performed on a custom pelvic anthropomorphic phantom model (CIRS)(phantom), using the prototype TF and custom NIH fusion software. The phantom underwent MRI and the prostate was segmented. The TF was placed in the phantom′s urethra and bladder and next underwent MRI/ultrasound fusion of the prostate using a BK 8818 transducer. Three targets were identified on the neurovascular bundles. Four trials were performed varying motion and the presence of the TF: 1: TF no motion, 2: TF with motion, 3: no TF, no motion, and 4: no TF, with motion. Artificial motion was induced by dropping the CT table for trials 2 and 4. After a needle was placed in each target location with fusion software, a CT scan was used to measure (average) distances from the tip of the needle to the intended target. RESULTS After artificial motion was induced, the group with no TF had a significantly higher average error distance than those with TF (6.4 mm vs 32.2 mm, p=0.0027). There was no difference in average error distance between no motion groups, with or without TF (5.6 mm vs 8.6 mm, p=0.28). There was no significant average error distance between TF with and without motion (5.56 vs 6.35, p=0.57). CONCLUSIONS The TF effectively reduced error distance after organ / patient motion in a catheterizeable custom pelvic phantom model. The TF maintains accurate MRI/prostate registration after simulated motion or position change of critical structures during procedures. This technology may lead to the more accurate merging of images for challenging prostate surgery or focal therapy. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e339 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Graham R. Hale More articles by this author Sheng Xu More articles by this author Samuel A. Gold More articles by this author Kareem N. Rayn More articles by this author Jonathan B. Bloom More articles by this author Sherif Mehralivand More articles by this author Neil Glossop More articles by this author Baris Turkbey More articles by this author Peter A. Pinto More articles by this author Brad Wood More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The effects of ground compliance on flexible planar passive biped dynamic walking

Passive biped dynamic walking exhibits humanoid gait. Many efforts have been made to implement a flexible and anthropomorphic passive model. However, the couple of flexible passive walker on compliant ground has not been well studied yet. The objective of this paper was to develop multibody dynamics for flexible passive walker on compliant ground, in which the nonlinear spring-damper contact model was used both in normal and tangential directions to represent ground compliance. Inspired by elastic mechanisms in human locomotion, hip stiffness and damping were incorporated in the proposed flexible passive walker. Different from traditional impactmomentum method, one unified set of continuous dynamics based on continuous force method was developed to describe the entire passive walking gait on compliant ground, including the real double support phase. Through numerical simulations, stable period-one gait and double support phase were gained. After investigating the effects of contact parameters on step length, period and velocity, it was found that larger contact stiffness and smaller contact damping lead to a higher step velocity gait. The adjustment of hip stiffness could be used to improve the versatility of the flexible walker on varying compliant grounds.

Human and model observer performance for lesion detection in breast cone beam CT images with the FDK reconstruction.

We investigate the detectability of breast cone beam computed tomography images using human and model observers and the variations of exponent, β, of the inverse power-law spectrum for various reconstruction filters and interpolation methods in the Feldkamp-Davis-Kress (FDK) reconstruction. Using computer simulation, a breast volume with a 50% volume glandular fraction and a 2mm diameter lesion are generated and projection data are acquired. In the FDK reconstruction, projection data are apodized using one of three reconstruction filters; Hanning, Shepp-Logan, or Ram-Lak, and back-projection is performed with and without Fourier interpolation. We conduct signal-known-exactly and background-known-statistically detection tasks. Detectability is evaluated by human observers and their performance is compared with anthropomorphic model observers (a non-prewhitening observer with eye filter (NPWE) and a channelized Hotelling observer with either Gabor channels or dense difference-of-Gaussian channels). Our results show that the NPWE observer with a peak frequency of 7cyc/degree attains the best correlation with human observers for the various reconstruction filters and interpolation methods. We also discover that breast images with smaller β do not yield higher detectability in the presence of quantum noise.

Patient dose in image guided radiotherapy: Monte Carlo study of the CBCT dose contribution

Image Guided RadioTherapy (IGRT) is a technique whose diffusion is growing thanks to the well-recognized gain in accuracy of dose delivery. However, multiple Cone Beam Computed Tomography (CBCT) scans add dose to patients, and its contribution has to be assessed and minimized. Aim of our work was to evaluate, through Monte Carlo simulations, organ doses in IGRT due to CBCT and therapeutic MV irradiation in head-neck, thorax and pelvis districts. We developed a Monte Carlo simulation in GAMOS (Geant4-based Architecture for Medicine-Oriented Simulations), reproducing an Elekta Synergy medical linac operating at 6 and 10 MV photon energy, and we set up a scalable anthropomorphic model. After a validation by comparison with the experimental quality indexes, we evaluated the average doses to all organs and tissues belonging to the model for the three cases of irradiated district. Scattered radiation in therapy is larger than that diffused by CBCT by one to two orders of magnitude.

Computer tomography-based body surface area evaluation for drug dosage: Quantitative radiology versus anthropomorphic evaluation.

ObjectiveThe measure of body surface area (BSA) is a standard for planning optimal dosing in oncology. This index is derived from a model having questionable performances. In this study, we proposed measurement of BSA from whole body CT images (iBSA). We tested the reliability of iBSA assessments and simulated the impact of our approach on patient chemotherapy dosage planning.MethodsWe first evaluated accuracy and precision of iBSA in measuring 14 phantom and 11 CT test-retest images.Secondly, we retrospectively analyzed 26 whole body PET-CT scans to evaluate inter-method variability between iBSA and the most used anthropomorphic models, notably the “Du Bois and Du Bois” model. Finally, we simulated the impact on chemotherapy dose planning of capecitabine based on iBSA.ResultsPrecision and accuracy of iBSA measurement featured a standard deviation of 1.11% and a mean error of 1.53%. Inter-method variability between iBSA and “Du Bois and Du Bois” assessment featured a standard deviation of 4.11% leading to a reclassification rate of capecitabine of 32.5%.ConclusionsiBSA could help the oncologist in standardizing assessments for chemotherapy planning. iBSA could also be relevant for applications such as comprehensive body composition and provide a sensitive measurement for changes related to nutritional intake or other metabolism.

Head, chest and femur injury in teenage pedestrian–SUV crash; mass influence on the speeds

This work studies the teenage pedestrian–sport utility vehicle (SUV) crash; injury to the vital parts of the body, such as the head and chest, and to the femur is evaluated. More advanced injury criteria are applied, as provided in the rules. The multibody technique is applied by making use of SimWise software and of the teenager anthropomorphic model, the use of which is now consolidated. Head injury criterion (HIC) is used for the head, thoracic trauma index (TTI) criterion for the thorax in the case of side impact and 3 ms criterion in the case of frontal impact, while the force criterion is used for the femur. Both the TTI and femur load evaluation require non-substantial modifications of the dummy, by insertion of sensors for the measurement of the acceleration of the 4th rib and the 12th vertebra and two very thin plates at the knees for the correct individuation of the contact point with the vehicle bumper. Particular attention is paid to the front shape of the vehicle, concluding that the SUV examined in this paper is less dangerous than the sedan studied in a previous work, since its frontal dimensions (bonnet angle, bumper height and bonnet height) are more advantageous. However the teenage pedestrian in a lateral position is less prone to injuries in the head and chest, with respect to the frontal position; the pedestrian’s position has little influence on femur damage. Furthermore, the braking of the vehicle reduces the possibility of crash fatality. In conclusion, a theoretical approach is shown, to highlight the influence of the vehicle mass on the pedestrian speed after the impact.

A 3D subject-specific model of the spinal subarachnoid space with anatomically realistic ventral and dorsal spinal cord nerve rootlets

BackgroundThe spinal subarachnoid space (SSS) has a complex 3D fluid-filled geometry with multiple levels of anatomic complexity, the most salient features being the spinal cord and dorsal and ventral nerve rootlets. An accurate anthropomorphic representation of these features is needed for development of in vitro and numerical models of cerebrospinal fluid (CSF) dynamics that can be used to inform and optimize CSF-based therapeutics.MethodsA subject-specific 3D model of the SSS was constructed based on high-resolution anatomic MRI. An expert operator completed manual segmentation of the CSF space with detailed consideration of the anatomy. 31 pairs of semi-idealized dorsal and ventral nerve rootlets (NR) were added to the model based on anatomic reference to the magnetic resonance (MR) imaging and cadaveric measurements in the literature. Key design criteria for each NR pair included the radicular line, descending angle, number of NR, attachment location along the spinal cord and exit through the dura mater. Model simplification and smoothing was performed to produce a final model with minimum vertices while maintaining minimum error between the original segmentation and final design. Final model geometry and hydrodynamics were characterized in terms of axial distribution of Reynolds number, Womersley number, hydraulic diameter, cross-sectional area and perimeter.ResultsThe final model had a total of 139,901 vertices with a total CSF volume within the SSS of 97.3 cm3. Volume of the dura mater, spinal cord and NR was 123.1, 19.9 and 5.8 cm3. Surface area of these features was 318.52, 112.2 and 232.1 cm2 respectively. Maximum Reynolds number was 174.9 and average Womersley number was 9.6, likely indicating presence of a laminar inertia-dominated oscillatory CSF flow field.ConclusionsThis study details an anatomically realistic anthropomorphic 3D model of the SSS based on high-resolution MR imaging of a healthy human adult female. The model is provided for re-use under the Creative Commons Attribution-ShareAlike 4.0 International license (CC BY-SA 4.0) and can be used as a tool for development of in vitro and numerical models of CSF dynamics for design and optimization of intrathecal therapeutics.