: Rupture risk assessment is a key to devise patient-specific treatment plans of cerebral aneurysms. To understand and predict the development of aneurysms and other vascular diseases over time, both hemodynamic flow patterns and their effect on the vessel surface need to be analyzed. Flow structures close to the vessel wall often correlate directly with local changes in surface parameters, such as pressure or wall shear stress. However, especially for the identification of specific blood flow characteristics that cause local startling parameters on the vessel surface, like elevated pressure values, an interactive analysis tool is missing. In order to find meaningful structures in the entirety of the flow, the data has to be filtered based on the respective explorative aim. Thus, we present a combination of visualization, filtering and interaction techniques for explorative analysis of blood flow with a focus on the relation of local surface parameters and underlying flow structures. In combination with a filtering-based approach, we propose the usage of evolutionary algorithms to reduce the overhead of computing pathlines that do not contribute to the analysis, while simultaneously reducing the undersampling artifacts. We present clinical cases to demonstrate the benefits of both our filter-based and evolutionary approach and showcase its potential for patient-specific treatment plans.

Interest in the application of Computer Simulation within Medical training continues to grow and the use of the VERT (Virtual Environment for Radiotherapy Training) system in radiotherapy training equally so. Herein we explore the use of the VERT system to understand, illustrate and experience the process required to calibrate an ion chamber and use it to obtain an accurate output measurement on a high energy Linac. The VERT system provides a detailed and accurate simulation of conventional Linacs and has a variety of physics activities that mirror the tasks medical physicists are required to become familiar with during their training. One such activity has been implemented to follow the steps defined by the IAEA TRS398 protocol. All activities on the virtual Linac can be undertaken with deliberate errors having been introduced to explore their consequences. The system was used to make the necessary `measurements' to determine the various calibration factors required to correct the raw electrometer reading for ion recombination, polarity, temperature/pressure. Likewise, the Quality Index of the Linac's 6MV beam was determined to enable the correction of the Absorbed Dose to Water factor measured in the reference Quality. The VERT system provides a simulation environment for training and enhancing the trainees understanding of radiotherapy concepts and practices. Dosimetry practice can be experienced and explored in the classroom during standard working hours rather than waiting until a clinical Linac is available. Random and systematic errors can be introduced, however, the virtual machine can be used without risk of leaving it in a mis-calibrated or unsafe condition.

BACKGROUND: Surgical training has been greatly affected by the challenges of reduced training opportunities, shortened working hours, and financial pressures. There is an increased need for the use of training system in developing psychomotor skills of the surgical trainee.AIMS: To develop the training system for fracture fixation and validate its effectiveness in a cohort of junior orthopedic trainees.TRAINING SYSTEM: Computer-navigated training system uses the 2 sets of images from the c-arm while the registration phantom is placed in the fluoroscopic imaging space which permits determination of the position of the x-ray source and the image plane that then guides the trainee to navigate the surgical instruments into the three-dimensional space. No further c-arm exposures are taken during the entire procedure.MATERIAL AND METHODS: The training system was developed to simulate dynamic hip screw fixation. Twelve orthopedic senior house officers performed dynamic hip screw fixation before and after the training on the training system. The results were assessed based on the scoring system that included the amount of time taken, accuracy of guidewire placement, and the number of exposures requested to complete the procedure.RESULTS: The result shows a significant improvement in the amount of time taken, accuracy of fixation, and the number of exposures after the training on the simulator system. The paired student t-test was used and statistically significant results were obtained (p-value < 0.05).CONCLUSION: Computer-navigated training system appears to be a good training tool for young orthopedic trainees. This system can be used to augment training in the operating room and trainees acquire their skills in a "nonthreatening and unhurried environment." The system has the potential to be used in various other orthopedic procedures for learning of technical skills in a manner aimed at ensuring a smooth escalation in task complexity leading to the better performance of procedures in the operating theater. (J Surg 70:304-308. (C) 2013 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.)

When observing another individual's actions, we can both recognize their actions and infer their beliefs concerning the physical and social environment. The extent to which visual adaptation influences action recognition and conceptually later stages of processing involved in deriving the belief state of the actor remains unknown. To explore this we used virtual reality (life-size photorealistic actors presented in stereoscopic three dimensions) to see how visual adaptation influences the perception of individuals in naturally unfolding social scenes at increasingly higher levels of action understanding. We presented scenes in which one actor picked up boxes (of varying number and weight), after which a second actor picked up a single box. Adaptation to the first actor's behavior systematically changed perception of the second actor. Aftereffects increased with the duration of the first actor's behavior, declined exponentially over time, and were independent of view direction. Inferences about the second actor's expectation of box weight were also distorted by adaptation to the first actor. Distortions in action recognition and actor expectations did not, however, extend across different actions, indicating that adaptation is not acting at an action-independent abstract level but rather at an action-dependent level. We conclude that although adaptation influences more complex inferences about belief states of individuals, this is likely to be a result of adaptation at an earlier action recognition stage rather than adaptation operating at a higher, more abstract level in mentalizing or simulation systems.

Prior research based on static images has found limited improvement for recognising previously learnt faces in a new expression after several different facial expressions of these faces had been shown during the learning session. We investigated whether non-rigid motion of facial expression facilitates the learning process. In Experiment 1, participants remembered faces that were either presented in short video clips or still images. To assess the effect of exposure to expression variation, each face was either learnt through a single expression or three different expressions. Experiment 2 examined whether learning faces in video clips could generalise more effectively to a new view. The results show that faces learnt from video clips generalised effectively to a new expression with exposure to a single expression, whereas faces learnt from stills showed poorer generalisation with exposure to either single or three expressions. However, although superior recognition performance was demonstrated for faces learnt through video clips, dynamic facial expression did not create better transfer of learning to faces tested in a new view. The data thus fail to support the hypothesis that non-rigid motion enhances viewpoint invariance. These findings reveal both benefits and limitations of exposures to moving expressions for expression-invariant face recognition.

Facial expression is a major source of image variation in face images. Linking numerous expressions to the same face can be a huge challenge for face learning and recognition. It remains largely unknown what level of exposure to this image variation is critical for expression-invariant face recognition. We examined this issue in a recognition memory task, where the number of facial expressions of each face being exposed during a training session was manipulated. Faces were either trained with multiple expressions or a single expression, and they were later tested in either the same or different expressions. We found that recognition performance after learning three emotional expressions had no improvement over learning a single emotional expression (Experiments 1 and 2). However, learning three emotional expressions improved recognition compared to learning a single neutral expression (Experiment 3). These findings reveal both the limitation and the benefit of multiple exposures to variations of emotional expression in achieving expression-invariant face recognition. The transfer of expression training to a new type of expression is likely to depend on a relatively extensive level of training and a certain degree of variation across the types of expressions.

A retrospective review of 57 military patients undergoing ankle arthroscopy between 1999 and 2011 was performed. A case-note review of medical records was undertaken pertaining to military role, ankle injury sustained, mechanism, presenting symptoms and their duration. Arthroscopic findings were compared to findings on radiographs and MRI scans. At first presentation 23 patients had features of arthritis on radiographs. We found MRI was both highly sensitive (97.7%) and specific (93.4%) in detecting osteochondral defects (OCD). 16 of the patients had evidence of osteochondral injury. All OCDs picked up on MRI were confirmed at arthroscopy. Ankle injury may not be a benign injury in military personnel, with over half of these young patients having radiological features of osteoarthritis at presentation. We found MRI an effective tool for identifying occult injuries not seen on radiographs. Lateral ligament injury with associated gutter scarring can be successfully treated with arthroscopic debridement. This suggests pseudoinstability rather than a true mechanical instability as the main cause for patient9s symptoms in this cohort.

Purpose: In recent years there has been interest in using Computer Simulation within Medical training. The VERT (Virtual Environment for Radiotherapy Training) system is a Flight Simulator for Radiation Oncology professionals, wherein fundamental concepts, techniques and problematic scenarios can be safely investigated.Methods: The system provides detailed simulations of several Linacs and the ability to display DICOM treatment plans. Patients can be mis-positioned with 'set-up errors' which can be explored visually, dosimetrically and using IGRT. Similarly, a variety of Linac calibration and configuration parameters can be altered manually or randomly via controlled errors in the simulated 3D Linac and its component parts. The implication of these can be investigated by following through a treatment scenario or using QC devices available within a Physics software module.Results: One resultant exercise is a systematic mis-calibration of 'lateral laser height' by 2mm. The offset in patient alignment is easily identified using IGRT and once corrected by reference to the 'in-room monitor'. The dosimetric implication is demonstrated to be 0.4% by setting a dosimetry phantom by the lasers (and ignoring TSD information). Finally, the need for re-calibration can be shown by the Laser Alignment Phantom or by reference to the front pointer.Conclusions: The VERT system provides a realistic environment for training and enhancing understanding of radiotherapy concepts and techniques. Linac error conditions can be explored in this context and valuable experience gained in a controlled manner in a compressed period of time.

The Automated Planet Finder (APF) is a facility purpose-built for the discovery and characterization of extrasolar planets through high-cadence Doppler velocimetry of the reflex barycentric accelerations of their host stars. Located atop Mt. Hamilton, the APF facility consists of a 2.4-m telescope and its Levy spectrometer, an optical echelle spectrometer optimized for precision Doppler velocimetry. APF features a fixed format spectral range from 374 nm - 970 nm, and delivers a "Throughput" (resolution * slit width product) of 114,000 arc-seconds, with spectral resolutions up to 150,000. Overall system efficiency (fraction of photons incident on the primary mirror that are detected by the science CCD) on blaze at 560 nm in planet-hunting mode is 15%. First-light tests on the RV standard stars HD 185144 and HD 9407 demonstrate sub-meter per second precision (RMS per observation) held over a 3-month period. This paper reviews the basic features of the telescope, dome, and spectrometer, and gives a brief summary of first-light performance.

It is known that happy faces create more robust identity recognition memory than faces with some other expressions. However, this advantage was not verified against all basic expressions. Moreover, no research has assessed whether similar differences also exist among other expressions. To tackle these questions, we compared the effects of six basic emotional expressions on recognition memory using a standard old/new recognition task. The experiment also examined whether exposure to different emotional expressions at training creates variable effects on transfer of the trained faces to a new/neutral expression. Our results suggest that happy faces produced better identity recognition relative to disgusted faces, regardless of whether they were tested in the same image or a new image displaying a neutral expression. None of the other emotional expressions created measurable advantage for recognition memory. Overall, our data lend further support for the happy face advantage for long-term recognition memory. However, our detailed analyses also show that the advantage of happy expression on identity recognition may not be equally discernible from all other emotional expressions.

BACKGROUND: Simulation and surgical training has moved on since its inception during the end of the last century. The trainees are getting more exposed to computers and laboratory training in different subspecialties. More needs to be done in orthopedic simulation in spinal surgery.AIMS: To develop a training system for pedicle screw fixation and validate its effectiveness in a cohort of junior orthopedic trainees.TRAINING SYSTEM: Fully simulated computer-navigated training system is used to train junior orthopedic trainees perform pedide screw insertion in the lumbar spine. Real patient computed tomography scans are used to produce the real-time fluoroscopic images of the lumbar spine.MATERIAL AND METHODS: The training system was developed to simulate pedide screw insertion in the lumbar spine. A total of 12 orthopedic senior house officers performed pedide screw insertion in the lumbar spine before and after the training on training system. The results were assessed based on the scoring system, which included the amount of time taken, accuracy of pedide screw insertion, and the number of exposures requested to complete the procedure.RESULTS: The result shows a significant improvement in amount of time taken, accuracy of fixation, and the number of exposures after the training on simulator system. This was statistically significant using paired Student t test (p < 0.05).CONCLUSION: Fully simulated computer-navigated training system is an efficient training tool for young orthopedic trainees. This system can be used to augment training in the operating room, and trainees acquire their skills in the comfort of their study room or in the training room in the hospital. The system has the potential to be used in various other orthopedic procedures for learning of technical skills in a manner aimed at ensuring a smooth escalation in task complexity leading to the better performance of procedures in the operating theater. (C) 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

In vascular interventional radiology, procedures generally start with the Seldinger technique to access the vasculature, using a needle through which a guidewire is inserted, followed by navigation of catheters within the vessels. Visual and tactile skills are learnt in a patient apprenticeship which is expensive and risky for patients. We propose a training alternative through a new virtual simulator supporting the Seldinger technique: ImaGiNe (imaging guided interventional needle) Seldinger. It is composed of two workstations: (1) a simulated pulse is palpated, in an immersive environment, to guide needle puncture and (2) two haptic devices provide a novel interface where a needle can direct a guidewire and catheter within the vessel lumen, using virtual fluoroscopy. Different complexities are provided by 28 real patient datasets. The feel of the simulation is enhanced by replicating, with the haptics, real force and flexibility measurements. A preliminary validation study has demonstrated training effectiveness for skills transfer.

PURPOSERecently there has been a great deal of interest in the application of Simulation methodologies for training. We have previously developed a Virtual Environment for Radiotherapy Training, VERT, which simulates a fully interactive and functional Linac. Patient and plan data can be accessed across a DICOM interface, allowing the treatment process to be simulated. Here we present a newly developed range of Physics equipment, which allows the user to undertake realistic QC processes. Five devices are available: 1) scanning water phantom, 2) 'solid water' QC block/ion chamber, 3) light/ radiation field coincidence phantom, 4) laser alignment phantom and 5) water based calibration phantom with reference class and 'departmental' ion chamber.METHODSThe devices were created to operate realistically and function as expected, each has an associated control screen which provides control and feedback information. The dosimetric devices respond appropriately to the beam qualities available on the Linac. Geometrical characteristics of the Linac, e.g. isocentre integrity, laser calibration and jaw calibrations can have random errors introduced in order to enable the user learn and observe fault conditions. In the calibration module appropriate factors for temperature and pressure must be set to correct for ambient, simulated, room conditions.RESULTSThe dosimetric devices can be used to characterise the Linac beams. Depth doses with Dmax of 15mm/29mm and d10 of 67%/77% respectively for 10cm square 6/15MV beams were measured. The Quality Indices (TPR20/10 ratios) can be measured as 0.668 and 0.761 respectively.CONCLUSIONSAt a simple level the tools can be used to demonstrate beam divergence or the effect of the inverse square law; They are also designed to be used to simulate the calibration of a new ion chamber. We have developed a novel set of tools that allow education of Physics processes via simulation training in our virtual environment. Both Authors are Founders and Directors of Vertual Ltd, a spin-out company that exists to commericalise the results of the research work presented in this abstract.

PURPOSE:Recently there has been great interest in the use of simulation training, with the view to enhance safety within radiotherapy practice. We have developed a Virtual Environment for Radiotherapy Training (VERT) which facilitates this, including the simulation of a number of 'Physics practices'. One such process is the calibration of an ionisation chamber for use in Linac photon beams.METHODS:The VERT system was used to provide a life sized 3D virtual environment within which we were able to simulate the calibration of a departmental chamber for 6MV and 15 MV beams following the UK 1990 Code of Practice. The characteristics of the beams are fixed parameters in the simulation, whereas default (Absorbed dose to water) correction factors of the chambers are configurable thereby dictating their response in the virtual x-ray beam. When the simulation is started, a random, realistic temperature and pressure is assigned to the bunker. Measurement and chamber positional errors are assigned to the chambers. A virtual water phantom was placed on the Linac couch and irradiated through the side using a 10 × 10 field. With a chamber at the appropriate depths and irradiated iso-centrically, the Quality Indices (QI) of the beams were obtained. The two chambers were 'inter-compared', allowing the departmental chamber calibration factor to be calculated from that of the reference chamber.RESULTS:For the virtual 6/15 MV beams, the QI were found to be 0.668/ 0.761 and the inter-comparison ratios 0.4408/ 0.4402 respectively. The departmental chamber calibration factors were calculated; applying these and appropriate environmental corrections allowed the output of the Linac to be confirmed.CONCLUSIONS:We have shown how a virtual training environment can be used to demonstrate practical processes and reinforce learning. The UK CoP was used here, however any relevant protocol could be demonstrated. Two of the authors (Beavis and Ward) are Founders of Vertual Ltd, a spin-out company created to commercialise the research presented in this abstract.