Image-Guided Photodynamic Cancer Therapy

Abstract

Photodynamic therapy is a therapeutic modality with a long history. It has been historically known in ancient India and China for the treatment of skin disorders. In Western medicine, the first experimental evidence of photodynamic therapy was reported by Raab et al. who observed the lethality of acridine dyes to paramecium in the presence of light [1]. The photodynamic effect was further demonstrated by Tappeiner and colleagues who reported killing of basal cell carcinoma using eosin and light illumination [2]. More recently, Dougherty et al. developed a hematoporphyrin derivative, which was shown to kill cancer cells in vitro and mammary tumors in mouse models in vivo [3]. Photodynamic therapy has evolved as an effective therapeutic modality for cancer treatment. In 1995, the FDA approved photodynamic therapy using Photofrin for the treatment of advanced esophageal cancer. Recent developments in biomedical imaging provide new opportunities for photodynamic therapy. Modern imaging technologies can accurately detect and diagnose malignant tumors at an early stage and can effectively assess tumor response to cancer photodynamic therapy. Combining photodynamic therapy with imaging can provide image guidance for accurate laser irradiation of tumor and timely assessment of therapeutic efficacy of photodynamic therapy. Image-guided photodynamic therapy is a new, minimally invasive cancer treatment modality that can further improve the efficacy of photodynamic therapy.