Abstract:
Surgical lights play an important role in an operating theatre. This thesis investigates the potential of a novel automated ceiling-based surgical light system to address the limitations of current modern designs. These include large size, need for repositioning, shadow formation, heat generation, and contamination risk. Such limitations may hinder a surgeon's performance and have a negative e ect on the outcome of the surgery. Therefore, the aim was to develop a prototype that could automatically maintain a consistent level of illumination and eliminate shadows. This was achieved by placing LED light modules on the ceiling to illumi- nate the surgical area below. A sensor module measured the light intensity within this area and when light levels changed, it used a PID controller to maintain the desired brightness. The sensor and light modules communi- cated wirelessly to control LED brightness based on the PID output. When communication was interrupted due to the obstruction of light modules, the LEDs automatically dimmed leading to the elimination of any shadows. The prototype used 23 light modules which produced a maximum illumi- nation of 5,300 lux. These were set to maintain 50% of peak intensity, and their performance was measured using international standardised tests. In the cavity penetration test, the prototype was able to deliver and maintain 100% of the desired brightness. For the shadow control tests with one mask, one mask with standard tube and two masks, the prototype delivered 100% of desired brightness and for the test with two masks with standard tube, the prototype delivered 89%. The depth of illumination was measured to be 1.75m. These results show that consistent illumination was achieved and the shadows were eliminated. The prototype performed favourably when compared to the results of the shadow control tests of a typical modern surgical light (Bovie Med S1). The results further suggest that the proto- type, with the addition of extra light modules, has the potential to overcome limitations of modern surgical lights and replace them in operating theatres.