title: Targeted photodynamic therapy.
abstract: OBJECTIVE
  Photodynamic therapy (PDT) is an emerging modality for the treatment of various neoplastic and non-neoplastic pathologies.
  
  
  METHODS
  PDT usually occurs when reactive oxygen species (ROS) generated from light-activated chemicals (photosensitizer, PS) destroy the target. For non-dermatologic applications the PS are delivered systemically and accumulate, at different concentrations, in most organs.
  
  
  CONCLUSIONS
  Typically there is a modest enhanced accumulation of the PS in tumor tissues, providing a first level of selectivity. Additional selectivity is provided by the confined illumination of the target area with the appropriate wavelength of light. For the treatment of pathologies in complex anatomical sites, such as in the peritoneal cavity, where restricted illumination is difficult; improved targeting of the PS is necessary to prevent damage to the surrounding healthy tissue. This article will focus on targeted PDT.
authors: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors: Nicolas
authors: N
authors: Solban
authors: Imran
authors: I
authors: Rizvi
authors: Tayyaba
authors: T
authors: Hasan