Dose measurements in photodynamic therapy of cancer.

A theory and method for prediction and measurement of the effective absorbed dose in photodynamic therapy of cancer is presented. The method depends on measuring the concentration of the photosensitizer (such as dihematorporphyrin ether), the flux density of the light, and the relative photodynamic effectiveness. Previous, less exact methods relied on specifying the drug dosage and delay after injection and or the irradiance at the surface or power from an interstitial fiber. The new formulation should permit closer control of the effective absorbed dose and better clinical results with photodynamic therapy.