Photodynamic Therapy

References 399

1. INTRODUCTION

Photodynamic therapy (PDT) is a treatment modality that utilizes three elements, a

photosensitizing drug, light, and oxygen, to induce targeted cell death of neoplastic or abnor-

mal tissue (1). Specifically, sensitization of the target tissue is selective and occurs via the

topically or systemically administered photosensitizing agent. After administration, the

photosensitizer is activated by light and reacts with oxygen and other metabolites to

produce highly reactive oxygen intermediates and free radicals that result in destruction of

targeted tissue (2).