Clinical Simulator Research Articles

Logistic Regression Function for Detection of Suspicious Performance During Baseline Evaluations Using Concussion Vital Signs

This study utilized logistic regression to determine whether performance patterns on Concussion Vital Signs (CVS) could differentiate known groups with either genuine or feigned performance. For the embedded measure development group (n = 174), clinical patients and undergraduate students categorized as feigning obtained significantly lower scores on the overall test battery mean for the CVS, Shipley-2 composite score, and California Verbal Learning Test-Second Edition subtests than did genuinely performing individuals. The final full model of 3 predictor variables (Verbal Memory immediate hits, Verbal Memory immediate correct passes, and Stroop Test complex reaction time correct) was significant and correctly classified individuals in their known group 83% of the time (sensitivity = .65; specificity = .97) in a mixed sample of young-adult clinical cases and simulators. The CVS logistic regression function was applied to a separate undergraduate college group (n = 378) that was asked to perform genuinely and identified 5% as having possibly feigned performance indicating a low false-positive rate. The failure rate was 11% and 16% at baseline cognitive testing in samples of high school and college athletes, respectively. These findings have particular relevance given the increasing use of computerized test batteries for baseline cognitive testing and return-to-play decisions after concussion.

Silicone-Based Tissue-Mimicking Phantom for Needle Insertion Simulation

Silicone-based tissue-mimicking phantom is widely used as a surrogate of tissue for clinical simulators, allowing clinicians to practice medical procedures and researchers to study the performance of medical devices. This study investigates using the mineral oil in room-temperature vulcanizing silicone to create the desired mechanical properties and needle insertion characteristics of a tissue-mimicking phantom. Silicone samples mixed with 0, 20, 30, and 40 wt. % mineral oil were fabricated for indentation and needle insertion tests and compared to four types of porcine tissues (liver, muscle with the fiber perpendicular or parallel to the needle, and fat). The results demonstrated that the elastic modulus and needle insertion force of the phantom both decrease with an increasing concentration of mineral oil. Use of the mineral oil in silicone could effectively tailor the elastic modulus and needle insertion force to mimic the soft tissue. The silicone mixed with 40 wt. % mineral oil was found to be the best tissue-mimicking phantom and can be utilized for needle-based medical procedures.

Board 520 - Technology Innovations Abstract Development and Validation of Simulators for Pediatric Inguinal Hernia Management in France (Submission #427)

Introduction/Background Inguinal hernia is one of the most common conditions seen in pediatric practice, with 3-5% of newborns experiencing inguinal hernias. An incarcerated or strangulated hernia can result in intestinal necrosis and testicular or ovarian atrophy, while improper repair techniques can lead to recurrence, testicular torsion, or injury of spermatic cord structures. Reduction of hernia contents back into the abdomen is a non-operative procedure that involves a series of simple but specific maneuvers that can prevent incarceration until surgery can be performed.1 No simulation models currently exist to teach an open approach to pediatric inguinal hernia repair nor maneuvers of inguinal hernia reduction. Because inguinal hernias are common, every physician should be adept at performing these procedures. The objective of this project is to develop and evaluate validity evidence for two simulators: a surgical simulator for pediatric inguinal hernia repair and a clinical simulator for pediatric inguinal hernia reduction. Methods Surgical Simulator: The surgical simulator consists of a plastic base with a pigmented silicone rubber covering. The spermatic cord model is secured inside the base and consists of a balloon representing the hernia sac, two elastic strings representing the spermatic vessels and vas deferens, and plastic wrap and silicone representing surrounding tissues. Fourteen novice raters and seventeen expert raters (N=31) from five different institutions in France (Nice, Paris, Strasbourg, Limoges, and Angers) performed the inguinal hernia repair. Participants completed a self-report rating scale ranging from 1 (Don’t know) to 5 (Very realistic, no changes needed). Validity evidence relevant to test content and internal structure was evaluated using the many-facet Rasch analysis. Analysis indicated that Attendings had higher ratings (Observed Average (OA)= 4.4/5.0) than Interns (OA=4.0) and Residents (OA=3.8), p=.001, and that there were overall differences when comparing ratings across institutions, with higher ratings associated with participants from Limoges (OA=4.56), followed by ratings from Nice (OA=4.25), Angers (OA=4.01), Strasbourg (OA=3.89), and Paris (OA=3.64), p=.01. Ratings across seven domains (Realism of materials, Realism of experience, Value, Internal anatomy, Ability to perform tasks, Relevance, Physical attributes) ranged from 3.91 to 4.41. The observed global rating was 2.37/4.0. Clinical Simulator: The clinical simulator consists of a modified baby doll with a pigmented silicone rubber covering. The hernia model inside the baby doll is represented by a sponge inside of a balloon, which can be manipulated from one end of the balloon to the other. Forty-eight novice raters, twenty expert raters, and ten non-identified raters (N=86) from the five institutions in France performed the inguinal hernia reduction. Participants completed a similar self-report rating scale ranging from 1 to 5. Validity evidence relevant to test content and internal structure was evaluated using the many-facet Rasch analysis. Analysis indicated no statistical differences when comparing Attending-specialists (Observed Average (OA)= 3.9/5.0) to Attending-generalists (OA=3.9) and Residents (OA=3.8), p=.97, but that there were overall differences when comparing ratings across institutions, with higher ratings associated with participants from Limoges and Angers (OA=3.9), followed by ratings from Strasbourg and Nice (OA=3.8), and Paris (OA=3.7), p=.001. Ratings across six domains (Ability to perform tasks, Realism of experience, Realism of materials, Physical attributes, Relevance, Value) ranged from 3.5 to 4.2. The observed global rating was 2.4/4.0. Results: Conclusion For the surgical simulator, participants agreed that the model has a great deal of value as a training and testing tool and is highly relevant to their clinical practice. For the clinical simulator, participants agreed that the model has some value as a training and testing tool and is relevant to their clinical practice. For both models, the observed global ratings indicate some need for improvement prior to implementation. Ratings of individual items within each domain will help us identify areas for improvement.

Time-to-simulation for radiation oncology patients in an academic department.

176 Background: In 2011, one of the two clinical simulators in our department was decomissioned in order to enable the construction of a clinical magnetic resonance (MR) simulator. As result, our clinical simulator capacity decreased resulting in increased wait times for patients undergoing treatment planning. In turn, there was a perceived increase in the number of patients added onto the simulator schedule (add-ons) immediately following consultation. This created problems of workflow on the simulator and increased clinic wait times for previously scheduled patients. A clinical Lean team was formed with the intent of 1) quantifying the number of daily add-ons and 2) identifying predictors of add-ons so that the frequency of add-ons could be predicted and if possible, load-leveled. Methods: Over an eight-week period, frequency of simulator add-ons was correlated with de-identified patient data abstracted from the medical record using one-way ANOVA and student t-tests to assess the statistical hypothesis that a patient, disease, or provider factor increased the likelihood of a patient add-on. Interviews were conducted with the clinical staff to determine perceived frequency of add-ons, predictors of add-ons, and to evaluate the rationale for add-ons. Results: On average, 7.9 (range 7.3-8.7) simulations were performed daily in our department and 0.95 (0.7-1.4) patients were added onto the simulator daily. Patient demographics, day of consultation, inpatient vs outpatient status, treating and referring physician, as well as cancer diagnosis were examined. A statistical trend for add-on patients on Friday (p=0.064, vs. Monday) was found. One physician's patients accounted for 36% of the Friday add-ons over the eight week period. The physician was interviewed and her rationale for adding-on patients was determined. Conclusions: The mean number of add-on patients was determined to be acceptably low in our department and was on average less than one patient daily. A trend for an increased likelihoood of add-on patients with a particular Friday provider was noted and as such future efforts will be directed at mitigating the number of this physician's add-on patients.

Clinical Trial Simulation To Assist In COPD Trial Planning And Design With A Biomarker-Based Diagnostic: When To Pull The Trigger?

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous disease with a wide range of clinical phenotypes that vary from predominantly airway disease (chronic bronchitis) to predominantly parenchymal disease (emphysema). Current advances for the treatment of COPD are increasingly focused on targeted treatments and development of novel biomarker-based diagnostics (Dx)'s to select the patients most likely to benefit. Clinical trial planning and design with biomarkers includes additional considerations beyond those for conventional trials in un-selected populations, e.g., the heterogeneity of COPD phenotypes in the population, the ability of a biomarker to predict clinically meaningful phenotypes that are differentially associated with the response to a targeted treatment, and the data needed to make Go/No Go decisions during clinical development.We developed the Clinical Trial Object Oriented Research Application (CTOORA), a computer-aided clinical trial simulator of COPD patient outcomes, to inform COPD trial planning with biomarkers. CTOORA provides serial projections of trial success for a range of hypothetical and plausible scenarios of interest. In the absence of data, CTOORA can identify characteristics of a biomarker-based Dx needed to provide a meaningful advantage when used in a clinical trial. We present a case study in which CTOORA is used to identify the scenarios for which a biomarker may be used successfully in clinical development. CTOORA is a tool for robust clinical trial planning with biomarkers, to guide early-to-late stage development that is positioned for success.

Using Modeling and Simulation in the Design of Closed-Loop Insulin Delivery System

The complexity of medical devices is rapidly increasing, enabled by innovations in technology. This same technology has enabled health care to expand from institutional environments to home care and mobile environments. Software plays a critical role in controlling these devices. It is essential that the dependability of these devices is assured because many of them are safety critical; i.e. can cause serious injury or death. Modeling and simulation of device designs is emerging among medical device manufacturers as a technique to help address such challenges. Modeling and simulation has a long history of improving product quality by helping designers to detect defects that may be overlooked in a traditional software development workflow. For example, design requirements can be modeled, and then the model checked for properties of requirement consistency and completeness. Subsequently, the model can be run in-silica permitting rapid-prototyping and comprehensive real-time checking of design behavior which can ultimately be used to help verify actual device implementation. Modeling can be thought of as an incremental process improvement step that happens early in a design phase well before any implementation (writing code or building physical hardware), and can be integrated into any software/hardware development lifecycle. Medical Devices manufacturers and companies in other safety-critical industries such as aerospace and automotive have been using modeling and simulation approaches to verify and validate designs early in their development process for many years now [4][7][8]. Today, many diabetic patients use insulin pumps to manage their own medication delivery through a combination of basal and bolus doses of insulin to maintain healthy blood glucose (BG) levels. With the addition of Continuous Glucose Monitoring (CGM) devices, the opportunity exists to create a closed-loop, automatic control or “artificial pancreas” means of delivering the insulin. In this technical brief, we present a highly abstracted insulin infusion pump system as an example modeling exercise. A simulated environment of the glycemic system of the body, along with the insulin computation algorithm are modeled in Simulink® and tested against various real-world parameters from clinical testing.

A pulsatile blood vessel system for a femoral arterial access clinical simulation model

The model-based, rapid-prototyping-enabled design and manufacture of a pulsatile blood vessel (PBV) for high-fidelity mannequin-based clinical simulations is presented. The PBV presented here is a pressurized, flexible tube with alternating fluid pressure created by a pump to mimic the behavior of a human vessel in response to pulsatile pressure. The use of PBVs is important for the fidelity of a clinical simulator that requires residents to palpate and/or access the vessel. In this study, a PBV is presented which features the integration of 3D modeling using patient-specific computed tomography (CT) data, mold fabrication using rapid-prototyping, and finite element method for estimating the required pumping pressure to generate the same level of force (about 1.5N) experienced by the user through palpation. The relationship between this palpation force and the vessel pressure is studied using two strategies: finite element analysis (FEA) and experiments in a femoral arterial access simulator with a pump, artificial vessel, and surrounding phantom tissue. The experimental results show a discrepancy of 8.7% from the FEA-predicted value. Qualitative validation is done by exposing and surveying 19 interventional cardiology residents at four major educational institutions to the simulator for accuracy of its feel. The overall survey results are positive.

Use of Ber-EP4 and Epithelial Specific Antigen to Differentiate Clinical Simulators of Basal Cell Carcinoma

EpCam is a transmembrane epithelial adhesion molecule present on all non-squamous epithelial cells. It is often overexpressed in certain carcinomas, such as breast and colon, and in dermatology, eg, basal cell carcinoma (BCC). Various monoclonal antibodies have been used to detect EpCam, including BerEP4 and epithelial specific antigen. We compared anti-EpCam clones, BerEP4, and epithelial specific antigen clone VU-1D9. One hundred and twelve lesions were stained with both antibodies. All basal cell carcinomas stained uniformly and strongly positive with both antibodies. Diffuse positive staining was also seen in all trichoepitheliomas and merkel cell carcinomas. Focal positive staining was seen in squamous cell carcinoma and benign sebaceous neoplasms. Clone VU-1D9 was more likely to produce focal positive staining as compared to BerEP4. This focal positive staining of sebaceous neoplasms and squamous cell carcinomas is a potential diagnostic pitfall.

Highland surgical boot camp—an apprenticeship in a week

Surgical training has changed: the apprenticeship model of training is dead, but what has taken its place? NHS Highland has developed the Highland surgical boot camp to help tackle this challenge. The boot camp is aimed at trainees at the beginning of their careers: early years specialty or core trainees and surgically minded foundation doctors. My course had nine participants from foundation year 1 to core training year 2. The excellent new Centre for Health Sciences at Raigmore Hospital in Inverness is a new facility with state of the art wet labs, clinical simulators, and a mock ward. The course was developed and is led by the general surgeons Angus Watson and Kenneth …

The use of self-mating PEEK as an alternative bearing material for cervical disc arthroplasty: a comparison of different simulator inputs and tribological environments

The hypothesis for this study was that the simulated wear behavior of a hydroxyapatite coated, self-mating PEEK cervical disc arthroplasty device would be dependent on the simulated testing environment. Five groups of devices were evaluated under suggested ASTM and ISO load and motion profiles. The groups utilized different testing frequencies and protein content of simulator fluid, in addition to assessing the potential for third body wear. The average wear rates were determined using linear regression analysis with a generalized estimating equation. Significant differences between groups were determined using the Wald's test. The simulated wear behavior was shown to be highly dependent on the testing environment, where protein content more than decreasing the cyclic loading frequency resulted in increased wear, but was not dependent on the suggested load and motion profiles. It was demonstrated that a self-mating PEEK cervical disc arthroplasty device has wear rates that are similar to existing material combinations for cervical disc arthroplasty. This study showed that at a time when data from retrieval analyses is deficient, it is important to test the wear resistance of cervical disc arthroplasty devices under various conditions. Long-term clinical results and ongoing implant retrievals are required for validation between clinical performance and simulator inputs.

A Metal/Ultrahigh-Molecular-Weight Polyethylene Cementless Surface Replacement

Cementless metal/ultrahigh-molecular-weight polyethylene (UHMWPE) hip replacements that use less than hemispherical acetabular components and a short tapered femoral stem were developed in 1983 by the use of cobalt-chromium alloy and conventional GUR 415 polyethylene sterilized by ethylene oxide. These devices improved the fixation failures seen with cemented, fully hemispherical acetabular cups but encountered wear and osteolysis problems in the medium to long term. More wear-resistant titanium nitride ceramic bearings, developed in 1989, coupled with porous coated, cementless fixation, demonstrated midterm survivorship of 91.8% at 6 years but also developed long-term wear and osteolysis problems associated with conventional polyethylene. Recent advances in wear-resistance with the use of highly crosslinked polyethylene has prompted a renewed examination of the cementless resurfacing concept, allowing bearing exchange and retention of well-fixed resurfacing implants with these improved bearings as well as primary resurfacing hip replacement, using conventional surgical techniques. An anticipated 60%-90% reduction in wear and osteolysis, on the basis of long-term clinical and mechanical simulator data, makes this cementless application a significant alternative to cemented metal-metal resurfacing.

Clinical Retrieval and Simulator Comparison of an Investigational Cervical Disc Replacement: An a Priori Requirement

IntroductionThe evolvement of cervical and lumbar disc replacement designs as alternatives to spinal fusion has resulted in a substantial number of ongoing United States Food and Drug Administration (FDA)-sponsored clinical trials. While these trials seek to establish “safety and effectiveness,” the

Emergency Cardiac Anterolateral Thoracotomy Simulator

Trauma is the leading cause of death in persons younger than 44 years old in America; half of the deaths occur within the first hour following the incident. The likelihood of survival for such critical trauma patients is significantly increased if an Emergency Department Thoracotomy (EDT) is performed. EDT entails the surgeon performing large and rapid incisions into the pleural space of the thoracic cavity to resuscitate patients who have suffered penetrating chest trauma. This procedure is highly invasive and rare and is typically conducted outside the operating theater in the absence of a trained cardiothoracic surgeon. Since most emergency clinicians are not trained to perform EDT and are often hesitant to perform it, poor outcomes are common. The use of clinical simulators offers the potential to eliminate these concerns; however, current medical simulators are not dedicated to the training of EDT. The goal of this work was to design and build a mechanical simulator to mimic the functionality of the rib cage and the components within the thoracic cavity to serve as a learning and assessment tool for conducting EDT. This design paper presents the user requirements and engineering specifications for the simulator, explains the materials selection approach employed for the thoracic components, and describes the iterative approach for designing, fabricating, and validating the EDT simulator.

Influence of Dentistry Students’ e-Learning Satisfaction: A Questionnaire Survey

Dental school graduates operating on patients without having had sufficient practice in school is potentially dangerous to the patients. In order to minimize this danger, it is necessary to establish a virtual learning environment for students. In this study, we incorporated DentSim, a clinical dentistry simulator, into an e-Learning platform. In addition to overcoming the time and space constraints on learning, DentSim can simulate clinical conditions. It also allows students to practice reading case histories and inspecting and diagnosing patients. To construct the research model for this study, we incorporated the four major factors for measuring e-Learner satisfaction-'learner interface', 'learning community', 'content' and 'personalization' with the variable of 'intention to use'. The subjects were 350 dental students studying at the College of Oral Medicine. The structural equation modeling (SEM) results showed that Factors that influenced 'intention to use' include 'learner interface', 'learning community' and 'personalization', and 'intention to use' affect 'e-Learner satisfaction' with the system.

Clinical Simulation in Modern Teaching and Training of Sonography in Obstetrics and Gynecology

Abstract Advances in computer technology, hardware and software have made ultrasound a diagnostic imaging technique of choice in certain areas of medicine or specialties such as obstetrics and gynecology. In teaching and training of obs/gyne ultrasonography, medical educators can utilize different forms of clinical simulators: traditional standardized patients and standard ultrasound diagnostic equipment, computer-based simulators, ultrasound simulators or ultrasound simulators with manikins. The popularity of a simulator is determined not only by its features, ease of use and cost, but also by its available learning modules and applications. Technology in ultrasound and computers are rapidly advancing in enhancing the quality and miniaturizing ultrasound machines. Portable and handheld ultrasound equipments are quickly becoming indispensable diagnostic instruments in different health care settings especially the emergency rooms and physician offices. Concerns, however, remain related to the lack of competence of health care providers in using and interpreting results of ultrasound studies, and the needs to standardize the training in ultrasonography. It is important to have access to one or more ultrasound simulators; however, it is even more important to establish and integrate fundamental structure of training ultrasonography into the main training curriculum of undergraduate, graduate, and postgraduate medical education.

Adult self-healing papular mucinosis on genital skin

We report a unique case of papular mucinosis on genital skin. The lesion was initially misdiagnosed and mistreated as molluscum contagiosum. The histological sections showed a large amount of mucin with sparse plump fibroblasts. The papules resolved in a few weeks, indicating a very rare form of the adult variant of self-healing papular mucinosis. Genital localization of this peculiar mucinosis, which we suspect may be more common than reported, is an important clinical simulator of sexually transmitted disease, and correct diagnosis is important for appropriate treatment.

SU-FF-I-120: Monte Carlo Simulation of Thin-Film CdTe Detector Performance for Diagnostic Imaging Applications

Purpose: As a semiconductor material of high atomic number and density, cadmium telluride (CdTe) is highly suitable for direct radiation detection, producing electronic signal in response to incoming x-rays. Development of thin-film CdTe deposition techniques in recent years allows for manufacturing of low cost large-area detectors with superior imaging capabilities and outstanding radiation hardness. We investigate performance on thin-film CdTe based detector under a range of energies relevant to diagnostic imaging applications. Method and Materials: Our analysis is based on Monte Carlo modeling of the detector performance with MCNP5 package. In order to calculate input spectra for different tungsten anode voltages (kVp) of our clinical simulator unit, we performed series of output measurements required for spectra generation with Tungsten Anode Spectral Modeling using Interpolating Polynomials (TASMIP) algorithm. In the next step these generated spectra were ran through a 20 cm water phantom, representing an imaged patient and resulting in a set of primary photon spectra used for detector characterization. Finally, x-ray beam is set to fall normally at the detector surface through a narrow slit, following a typical setup for line spread function LSF(x) measurement. Results: We calculate frequency-dependent pre-sampling detective quantum efficiency DQE(f) for kVp voltages from 40 to 140 kV. Thickness of CdTe was varied from 10 to 1000 microns, covering the range of feasible thin-film devices. Conclusion: Thin-film CdTe based detector offers high performance and high spatial resolution due to low signal spreading inherent of direct detection design. In combination with low manufacturing cost of large-area flat panel device, the detector is decidedly suitable for critical all the diagnostic imaging applications.

Sclerosing ‘Mucinous’ Blue Nevus: A Clinical Simulator of Dermatofibroma

Abundant mucin deposition is an unusual finding for melanocytic lesions. This notion, however, should be toned down since mucin may be present in distinct melanocytic lesions. Indeed, following the first description of mucin depositions in neural differentiated naevi by Maize and Ackerman in 1987 1 this phenomenon was repeatedly observed.2,3,4,5 Especially in blue naevi mucin deposition is a peculiar observation. For blue naevi 5 variants are distinguished to avoid the misdiagnosis of melanoma with stromal mucin deposition6: (i) neural nevus, (ii) myxoid intradermal nevus, (iii) alveolar cellular blue nevus, (iiii) ancient melanocytic nevus, (v) sclerosing blue nevus. In 2003, Rongioletti and Innocenzi described the first two examples of sclerosing blue naevi with an abundant mucinous stroma. Herein, we describe the third case of this rare entity. It should be noted, that particularly this uncommon variant of a blue naevus is easily mistaken as desmoplastic-neurotropic melanoma in which the present stromal deposition of mucin is a more typical finding. A specimen from the right lower leg of a 53-year old man was referred to our dermatopathology department with the clinical diagnosis of a dermatofibroma. Clinically, the tumor appeared as a brown lesion with a regular and sharp border. The histopathological work up revealed a symmetrical, well circumscribed papule; the fibro-mucinous stroma contained spindle-shaped and dendritic melanocytes, which sometimes were arranged in whorls (Fig. 1A). Orderly arranged melanocytes in the periphery were characterized by pigmentation, as confirmed by melanin-staining. Melanophages were present as clearly seen in the reaction against CD68. Alcian blue staining confirmed the mucin deposition within the tumor and excluded an intradermal component (Fig. 1B). Immunohistochemical staining with Mart-1 (Fig. 1D) and S-100 confirmed both the nature and the distribution of the melanocytes. Notably no reaction was found against MIB-1 excluding a high proliferation rate (Fig. 1C). Thus all criteria for the diagnosis of a sclerosing mucinous blue naevus were fulfilled, and the differential diagnosis of a malignant melanoma was excluded. Moreover, the clinical diagnosis of a dermatofibroma was ruled out by lack of either epidermal changes or typical infiltrating pattern. Hemosiderin deposits which mimic melanin were excluded by special staining. Figure 1. (A) Fibro-mucinous stroma with spindle-shaped and dendritic melanocytes, which sometimes were arranged in whorls. Melanophages were present (20x Hematoxylin and Eosin). (B) Alcian blue staining confirmed the mucin deposition within the tumor (20x Mucin). ... The cause of mucin deposition in melanocytic lesions remains elusive. It was attributed to a partial involution of the respective lesions. Interestingly, the dermoscopy of the presented sclerotic blue nevus revealed a hypopigmented center; a notion which has been described before.7 In line with this hypothesis it is well established that cellularity of naevi decrease which age, whereupon melanocytes are replaced by fibrous matrix, mucin and sometimes fat.8 With the present case report we like to raise the awareness for this rare entity because of the momentous differential diagnosis. Further reports of such cases would help to learn more about its clinical, dermoscopic and histological features.

The Use of Clinical Simulation Systems to Train Critical Care Physicians

Intensive care units are complex and dynamic clinical environments in which the delivery of appropriate and timely care to critically ill patients depends on the integrated and efficient actions of providers with specialized training. The use of realistic clinical simulator systems can help to facilitate and standardize the training of critical-care physicians, nurses, respiratory therapists, and pharmacists without having the training process jeopardize the well-being of patients. In this article, we review the current state of the art of patient simulator systems and their applications to critical-care medicine, and we offer some examples and recommendations on how to integrate simulator systems into critical-care training.

The correlation evaluation of a tumor tracking system using multiple external markers

The purpose of this study is to evaluate the correlations between external markers and internal targets for radiation therapy of lung cancer patients. Using an infrared camera system coupled with a clinical simulator, the simultaneous motions of multiple external markers and an internal target were obtained. The correlation between external and internal signals was analyzed using a cross-covariance function. A linear regression model was employed to generate a composite signal from multiple external markers in order to predict the internal target motion. The external and internal signals, and their correlations, demonstrated a wide range of variation with respect to marker location, motion dimension, and breathing pattern. The performance of the composite signal indicates that when more external signals were taken into account, the mean correlation between the composite signal and internal signal was improved. This implies that a combination of multiple external signals might be an improved way to predict internal target motion. Also, since the characteristics of respiratory signals can vary significantly, certain methods of preprocessing and external signal combination are necessary.