Real-time treatment feedback guidance of Pleural PDT.

Pleural photodynamic therapy (PDT) has been used as an adjuvant treatment with lung-sparing surgical treatment for mesothelioma with remarkable results. In the current intrapleural PDT protocol, a moving fiber-based point source is used to deliver the light and the light dose are monitored by 7 detectors placed in the pleural cavity. To improve the delivery of light dose uniformity, an infrared (IR) camera system is used to track the motion of the light sources. A treatment planning system uses feedback from the detectors as well as the IR camera to update light fluence distribution in real-time, which is used to guide the light source motion for uniform light dose distribution. We have improved the GUI of the light dose calculation engine to provide real-time light fluence distribution suitable for guiding the surgery to delivery light more uniformly. A dual-correction method is used in the feedback system, so that fluence calculation can match detector readings using both direct and scatter light models. An improved measurement device is developed to automatically acquire laser position for the point source. Comparison of the effects of the guidance is presented in phantom study.