| Photodynamic therapy (PDT) is now in increasingly widespread clinical use for various oncologic and non-oncologic applications. Improved dosimetry is required, especially for interstitial applications. Explicit PDT dosimetry requires the independent measurement of all three treatment parameters: the treatment light, and concentrations of the photosensitiser and molecular oxygen. Development and performance of fluorescence-based multi-sensory fibre optic probes (MSPs) that enable multiple simultaneous point measurements in a given fluence rate gradient are presented, including the comparative accuracy of single, two and three-component MSPs versus an established detector. A method for selecting fluorophore combinations for the MSPs, as well as a Partial-Least-Squares (PLS)-based decomposition algorithm for analysis of the fluorescence spectra collected from the MSP are developed and tested. Monte Carlo simulations are used to determine the spatial resolution and simulated accuracy of the probes. In addition, single-sensor phosphor-based oxygen probes are characterized and presented as preliminary work for multi-sensory oxygen probes. |
