Explicit Dosimetry: Heterogeneity in Tissue Optical Properties

Photodynamic therapy (PDT) centers on the photochemical in-teraction of 3 principal components: light, photosensitizer, and oxygen. Over the past 25 years, much has been learned about the basic biophysical mechanisms of PDT, and in the future, a clear-er understanding of the physics of PDT will make it possible to translate this science into improved clinical treatments. This article explores the role of explicit dosimetry in PDT and the need for individualized determination of dosimetric parameters based on the heterogeneity of optical properties and photosensitizer drug concentration. In addition, the use of a navigation system to help deliver uniform light for pleural PDT is briefly discussed. (JNCC