Purpose: Photodynamic therapy (PDT) has been used intraoperatively to treat patients with malignant pleural mesothelioma. Currently, 8 light detectors are placed inside the pleural cavity to monitor the light fluence and the positions of the detectors are acquired manually before treatment. An updated navigation system is developed to simplify the pre-treatment procedure and provide real-time guidance during pleural PDT to improve light delivery.
Methods: The newly developed GUI allowed user communication with the camera using the latest computer model with visualization of the real-time light fluence distribution feedback. With newly developed algorithm, the detectors position could be extrapolated directly from the positioning data from navigation system along with dosimetry data so that it is no longer necessary to measure the detector position before PDT. The calculated light fluence was compared with data collected via the 8 detectors for validation.
Results: By application of the real-time display of light fluence rate map obtained from the navigation system onto a phantom study, we have showed that more uniform light distribution can be achieved, compared to the PDT using detectors only. We have demonstrated that the new semi-automatical software can be used to identify all detector positions from the navigation data and the light fluence rate data in 0.5 hours. A comparison between the extrapolated and measured detector position were compared to be within 3.18 ± 1.32 cm. The data processed at detector positions processed with the extrapolated detector positions was comparable to data processed with measured detector positions. Real-time display of 2D light fluence rate was demonstrated for PDT treatment over 0.5 hours.
Conclusion: The GUI and data processing algorithm of the navigation system has been updated, which is more versatile. The new system was developed to extrapolate detector positions and provide real-time feedbacks on 2D light fluence distribution in phantom studies.
Funding Support, Disclosures, and Conflict of Interest: NIH 1R01 EB028778, NIH 1P01CA 87971
Optical Dosimetry, Image Guidance, Surface Dose