SU‐C‐105‐02: Real‐Time Treatment Guidance Using An IR Navigation System for Pleural PDT

Purpose: Pleural photodynamic therapy (PDT) has been used in conjunction with surgical debulking of the tumorous tissue in treatment for mesothelioma. Uniform light fluence distribution is critical for effective and predictable PDT outcome. Current treatment methods involve monitoring the light dose delivered with 8 detectors that are located at various locations inside the pleural cavity. A tracking and real-time feedback system can be utilized to improve the uniformity of light. Methods: An infrared (IR) tracking camera to monitor the movement of the light source. The same system is used to determine the pleural contour geometry of the treatment area. This study examines the fluence (rate) delivered between measurement and calibration in phantom studies. Isotropic detectors were used for in-vivo light dosimetry. The tracking data for the light source was used to calculate the light fluence rate delivered which was then compared with the in-vivo measurement. The real-time feedback software developed shows the tracking data and calculations during treatment time, enabling more uniform treatment of the pleural cavity. Results: Using the real-time feedback system, we are able to match the calculated fluence rate with the in-vivo measurements. Furthermore, we are able to treat more effectively and uniformly with the feedback software. The light fluence rate can have up to 50% deviation compared to the prescription in phantom experiments. With the navigation system, we are able to collect more data regarding the light delivered and the location to which the light was delivered. Conclusion: The IR camera has been used successfully during pleural PDT patient treatment to track the motion of the light source. It is possible to use the feedback system to deliver a more uniform dose of light throughout the pleural cavity.