Characterization of optical and thermal distributions from an intracranial balloon applicator for photodynamic therapy
- Author(s): Madsen, SJ
- Svaasand, LO
- Tromberg, BJ
- Hirschberg, H
- et al.
Published Web Locationhttps://doi.org/10.1117/12.434743
An indwelling balloon applicator developed for postoperative intracavity brachytherapy was evaluated for photodynamic therapy. Measurements of light distributions in a brain phantom show that the applicator can be used to deliver sufficiently uniform light doses during PDT. The light distribution is uniform to within 5% when the balloon is filled with a scattering medium. Based on simple assumptions, it is shown that the applicator can be used to deliver a threshold optical dose to brain tissue at depths of 1.4 cm in less than 90 minutes. A mathematical model of the thermal distribution around the applicator suggests that tissue temperatures will be below the hyperthermic threshold at the input powers required for treatments to depths of 1.4 cm in the resection cavity. The delivery of threshold light doses to depths exceeding 1.4 cm is likely to result in hypertherrnic effects to tissues near the applicator surface.