Fluence Rate Dosimetry for Photodynamic Therapy (PDT)

It has been demonstrated that the fluence rate at the tissue surface may differ significantly from the incident irradiance of light because of multiple scattering and absorption, both of which may vary among patients and tissue types. This AAPM TG report will review the current state-of-the-art fluence rate dosimetry technology. It will describe the two types of detectors currently available for fluence rate measurement, scattering-tip and fluorescence-based detectors, and review their principles of operation. Long term stability the in-air calibration coefficient of isotropic detector has been established to be ±10% using an integrating sphere setup. Various correction factors (medium correction factor beta, backscatter correction factor alpha) was established for common isotropic detectors. The report will recommend strategies to establish calibration and quality assurance procedures for clinical fluence rate dosimetry equipment, and it will establish guidelines for clinical implementation of fluence rate dosimetry.