Validity of a virtual reality endoscopic retrograde cholangiopancreatography simulator: can it distinguish experts from novices?

BackgroundThere is a lack of evidence regarding the effectiveness of virtual simulators as a means to acquire hands-on exposure to endoscopic retrograde cholangiopancreatography (ERCP). The present study aimed to assess the outcome and construct validity of virtual ERCP when training on the GI II Mentor simulator.MethodsA group of seven experienced endoscopists were compared with 31 novices. After a short introduction, they were requested to carry out three virtual ERCP procedures: diagnosing and removing a common bile duct (CBD) stone; diagnosing and taking brush cytology from a hilar stenosis; and, finally, diagnosing and treating a cystic leakage with a BD stent. For each task, the total time required to complete the task, time required to correctly view the papilla, total time of irradiation, time to deep cannulation, time to define diagnosis, time to complete sphincterotomy, and time to complete the respective intervention were measured. Cannulation of the BD, correct diagnosis, sphincterotomy, and time to complete intervention were assessed by an assessor blinded to the status of the endoscopist who performed the virtual ERCP.ResultsThe time required to visualize the papilla and to cannulate deeply when removing the BD stone was significantly shorter for the experts (both p < 0.05). The time to visualize the papilla, cannulate deeply, reach a diagnosis, complete sphincterotomy, and complete the intervention was significantly shorter for the experts when managing cystic leakage (all p < 0.05). In diagnosing and taking brush cytology from a hilar stenosis, there was only a trend toward the experts needing less time for the deep cannulation of the BD (p = 0.077).ConclusionThe performance differed between experts and novices, especially in the management of cystic leakage. This corroborates the construct validity of the GI II Mentor simulator

Ανάπτυξη τομοσπινθηρογραφικού συστήματος υψηλής ευαισθησίας και διακριτικής ικανότητας

In Single Photon Emission Computed Tomography (SPECT) planar images are taken with the use of a gamma Camera, the physical operating principle of which remains unchanged for almost half a century. This PhD thesis had as main objective the development of a modern small field gamma Camera system with high sensitivity and resolution, based on modern techniques. Along with the study of the individual parts of the gamma Camera (collimator, scintillation crystals, Postiotion Sensitive PhotoMultiplier Tube - PSPMT) a detailed study of the system was done at the level of simulations with the use of software GEANT4/Gate, to select the appropriate scintillators and to determine the best geometrical parameters. A series of corrective algorithms were developed and implemented at planar images. The whole system was evaluated through series of experimental tests in planar, and in tomographic level characterized by a spatial resolution better than a millimeter.Στην Μονοφωτονική Τομοσπινθηρογραφία τύπου SPECT (Single Photon Emission Computed Tomography) η λήψη προβολικών εικόνων γίνεται με την βοήθεια γ-Κάμερα, η φυσική αρχή λειτουργίας της οποίας παραμένει αμετάβλητη εδώ και μισό σχεδόν αιώνα. Η εκπόνηση της παρούσας Διδακτορικής Διατριβής είχε σαν κεντρικό στόχο την ανάπτυξη ενός σύγχρονου τέτοιου συστήματος μικρού πεδίου αλλά με υψηλή ευαισθησία και διακριτική ικανότητα, βασισμένου σε μοντέρνες τεχνικές. Παράλληλα με την μελέτη των επιμέρους συνθετικών μερών της γ-Κάμερα (κατευθυντήρας, κρύσταλλοι σπινθηρισμού, χωρικά ευαίσθητος φωτοπολλαπλασιαστής) έγινε ενδελεχής μελέτη του συστήματος σε επίπεδο προσομοιώσεων με το λογισμικό GEANT4/Gate, έτσι ώστε να επιλεγούν οι καταλληλότεροι σπινθηριστές και να καθοριστούν οι βέλτιστες γεωμετρικές παράμετροι. Αναπτύχθηκαν και εφαρμόστηκαν σειρά από διορθωτικούς αλγορίθμους σε επίπεδο προβολικής εικόνας. Το ολοκληρωμένο εργαστηριακό σύστημα αξιολογήθηκε μέσα από σειρά πειραματικών ελέγχων τόσο σε προβολικό, όσο και σε τομογραφικό επίπεδο και χαρακτηρίζεται από μια χωρική διακριτική ικανότητα καλύτερη του χιλιοστομέτρου

Study of corporate failure prediction using logistic regression and COX survival analysis

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Μαθηματική Προτυποποίηση σε Σύγχρονες Τεχνολογίες στην Οικονομία

The Effect of Health Education on Adolescents' Awareness of HPV Infections and Attitudes towards HPV Vaccination in Greece

Background: The purpose of this paper is to evaluate the role of health education among young adolescents, regarding their level of knowledge about the HPV and the acceptance of the HPV vaccination, with the aim of increasing vaccination coverage, in Trikala city, mainland of Greece. Methods: This study included high school students from all public and private schools of Trikala city. Questionnaires related to knowledge regarding the HPV infection and HPV vaccination were administered in three phases. In the first phase of the study, the questionnaires were completed by the entire study population. During the second and third phases, the completion of the questionnaires concerned only the population that received the intervention (interactive seminars). The second and third phase questionnaires were completed immediately after the interactive seminar and three months later, respectively. The statistical analysis of the results was performed using IBM SPSS 20.0 statistical program. Results: A total of 434 female students completed the questionnaire (response rate 76.26%). Most participants (66.6%) were females. The questionnaires evaluated the respondents’ awareness of the HPV infection. The results show that the percentage of the participants who stated that they “do not know” what HPV is decreased from 44.4% (first phase), to 1.6% (second phase), and 8.1% (third phase). Similarly, the willingness to accept the HPV vaccine increased from 71% (first phase), to 89.1% (second phase), and 83.5% (third phase). Conclusions: The present study shows that targeted interactive informational interventions in the school environment leads to a statistically significant increase in both the level of knowledge about HPV and the willingness of young adolescent students to be vaccinated against cervical cancer

Monte Carlo-Based Radiobiological Investigation of the Most Optimal Ion Beam Forming SOBP for Particle Therapy

Proton (p) and carbon (C) ion beams are in clinical use for cancer treatment, although other particles such as He, Be, and B ions have more recently gained attention. Identification of the most optimal ion beam for radiotherapy is a challenging task involving, among others, radiobiological characterization of a beam, which is depth-, energy-, and cell type- dependent. This study uses the FLUKA and MCDS Monte Carlo codes in order to estimate the relative biological effectiveness (RBE) for several ions of potential clinical interest such as p, 4He, 7Li, 10Be, 10B, and 12C forming a spread-out Bragg peak (SOBP). More specifically, an energy spectrum of the projectiles corresponding to a 5-cm SOBP at a depth of 8 cm was used. All secondary particles produced by the projectiles were considered and RBE was determined based on radiation-induced Double Strand Breaks (DSBs), as calculated by MCDS. In an attempt to identify the most optimal ion beam, using the latter data, biological optimization was performed and the obtained depth–dose distributions were inter-compared. The results showed that 12C ions are more effective inside the SOBP region, which comes at the expense of higher dose values at the tail (i.e., after the SOBP). In contrast, p beams exhibit a higher DSOPB/DEntrance ratio, if physical doses are considered. By performing a biological optimization in order to obtain a homogeneous biological dose (i.e., dose × RBE) in the SOBP, the corresponding advantages of p and 12C ions are moderated. 7Li ions conveniently combine a considerably lower dose tail and a DSOPB/DEntrance ratio similar to 12C. This work contributes towards identification of the most optimal ion beam for cancer therapy. The overall results of this work suggest that 7Li ions are of potential interest, although more studies are needed to demonstrate the relevant advantages. Future work will focus on studying more complex beam configurations

Use of saliva stress biomarkers to estimate novice male endoscopist's stress during training in a high-end simulator

Objective Simulated endoscopic training can be challenging and stressful for the novice trainee. The absence of a reliable stress detection method during simulated endoscopic training makes estimating trainees' mental stress difficult to quantify. This study concomitantly measures the responses of four saliva stress biomarkers and compares them to the video score (VS) achieved by novice endoscopists in a reproducibly stressful simulation environment. Methods Thirty-six male endoscopy naive surgery residents were enrolled. After an orientation phase, a saliva specimen was collected for cortisol (sC), alpha-amylase (sAA), Chromogranin A (sCgA), and immunoglobulin A (sIgA) measurements (baseline phase, BL). Thereafter, the simulation exercise phase (E) started, practicing in the Fundamentals of Endoscopic Surgery Skills module (GI-Bronch Mentor). Immediately after, a second saliva sample for measuring the above-cited biomarkers was collected. The whole experiment was videotaped, and the VS was calculated. The percentage (E-BL)(diff) of each of the four saliva biomarkers was calculated and examined for correlation to VS. Results sCgA(diff) showed the best correlation with VS, followed by sAA(diff). Conclusions sCgA and sAA, are saliva stress biomarkers that are easy to collect non-invasively and showed the best correlation with novice endoscopist's performance in our simulation setting, and therefore, they could be used for monitoring stress

Use of saliva stress biomarkers to estimate novice male endoscopist’s stress during training in a high-end simulator

Objective: Simulated endoscopic training can be challenging and stressful for the novice trainee. The absence of a reliable stress detection method during simulated endoscopic training makes estimating trainees’ mental stress difficult to quantify. This study concomitantly measures the responses of four saliva stress biomarkers and compares them to the video score (VS) achieved by novice endoscopists in a reproducibly stressful simulation environment. Methods: Thirty-six male endoscopy naïve surgery residents were enrolled. After an orientation phase, a saliva specimen was collected for cortisol (sC), alpha-amylase (sAA), Chromogranin A (sCgA), and immunoglobulin A (sIgA) measurements (baseline phase, BL). Thereafter, the simulation exercise phase (E) started, practicing in the Fundamentals of Endoscopic Surgery Skills module (GI-Bronch Mentor). Immediately after, a second saliva sample for measuring the above-cited biomarkers was collected. The whole experiment was videotaped, and the VS was calculated. The percentage (E-BL)diff of each of the four saliva biomarkers was calculated and examined for correlation to VS. Results: sCgAdiff showed the best correlation with VS, followed by sAAdiff. Conclusions: sCgA and sAA, are saliva stress biomarkers that are easy to collect non-invasively and showed the best correlation with novice endoscopist’s performance in our simulation setting, and therefore, they could be used for monitoring stress