Mark Wefers Bettink

Chapter 3 48 2.3 Monitor description The COMET is a medical device and class IIa classified according to the Medical Device Directive 93/42/EEC. The legal manufacturer is Photonics Healthcare B.V., Utrecht, The Netherlands. It weighs 10 kg and sizes 22 x 33 x 29 cm without cradle and port cover on the side. The COMET measurement system exists of two components shown in figure 1. The first component is the monitor which includes the multi-touch screen integrated user interface, light source, detection system and processing units. The second component is the COMET Skin Sensor developed for use on the human skin. Fig.1 COMET monitor and skin sensor. 2.3.1 Hardware The COMET is an electrically powered system (rated power consumption of 250 W). The light source and the detection system are the two core components. A 515 nm pulsed laser, pulse duration 60ns, with a 10Hz repetition rate illuminates the intra cellular accumulated PpIX. The fluorescent signal is projected on a gated red-sensitive