Purpose: Photodynamic therapy (PDT) is used intraoperatively to treat malignant pleural mesothelioma. To achieve efficiency of PDT, it is crucial to deliver light dose uniformly. Currently, 8 light detectors are placed inside the pleural cavity to monitor the light fluence. A navigation system is developed to provide real-time information of the light dose delivery during the PDT treatment and improve the uniformity of light fluence further.
Methods: An infrared (IR) tracking camera is used to track passive reflective markers on various wands, including treatment, contour and reference wands. Each wand can be identified automatically via its unique configuration. The newly developed software allows user communication with the camera. It also contains a user interface which visualizes the real-time feedback. The data presented is stored and can be exported for determination of the cavity geometry and light fluence calculation. These functions are integrated into the newly developed software. The calculated light fluence is also compared with data collected via the 8 detectors.
Results: For application on a chest phantom, it showed that the light distribution was more uniform with the real-time feedback provided by the navigation system, compared to the distribution with detectors only. Furthermore, the navigation system allows 2D light fluence collection throughout the whole phantom rather than just the selected points. Light fluence distribution can be calculated based on that for further analysis.
Conclusion: The navigation system is compatible with the latest computer operation system so that it can utilize the up-to-date hardware to speed up data processing and enable the system to provide real-time feedback. The system has been used successfully on chest phantom for the light source tracking and real-time display of 2D light fluence. It is possible to apply the system onto pleural PDT patient treatment for the purpose of a more uniform light dose delivery.