Guest Editors' Introduction: Simulators and closed interaction loops

Simulation systems for medical training and treatment planning should create an immersive and realistic feeling similar to treating a real patient. They should provide realistic views, support haptic feedback, and enable instrument handling. In addition, they must simulate tissue deformations and/or tissue removal. Some simulators already exist for isolated, rather simple areas, such as endoscopic or minimally invasive procedures (laparoscopy, colonoscopy, bronchoscopy, and so on), however there is a large need for systems that simulate open surgery (example, on the liver or heart). Simulators will play a fundamental role in teaching, training, and quality assurance for the coming generations.