Photomedicine

Definition

Photomedicine is an interdisciplinary branch of medicine that involves the study and application of light with respect to health and disease. Photomedicine may be related to the practice of various fields of medicine including dermatology, surgery, dentistry, optical diagnostics, cardiology, and oncology.

The ancient Greek historian Herodotus recorded the therapeutic use of sunlight or heliotherapy for skin lesions. Photomedicine was developed into a science and popularized by Niels Finsen, a Faroe Island physician who won the Nobel Prize in 1903.

Photomedicine can be divided into several specialities:

• Photobiology
• Photopheresis
• Photodynamics
• Phototherapy
• Photoimmunology

Effects of Photomedicine

Wellman Center for Photomedicine Composite image showing a newly developed endoscope projecting a light spectrum on tissue

Photomedicine, which includes photodynamic diagnosis (PDD) and photodynamic therapy (PDT), is based on the application of a photosensitizer relatively selective for malignant tissue. Light activation of appropriate wavelength leads to either fluorescence for diagnostic purposes or to oxidation-mediated tissue destruction for treatment.

There are broad, fundamental reasons to pursue photomedicine – light has the right quantum energy to trigger specific non-ionizing chemistry in drugs and tissues; tissue interactions unique to high-intensity laser light are very useful in medicine; and light based diagnostic and therapeutic interventions can often be designed to be minimally invasive and selectively targeted.

Because of its high tumor selectivity, excellent cosmetic effect and low toxicity, photomedicine seems to be a promising tool for the diagnosis and treatment of superficial skin cancer, lung and tracheobronchial cancer, esophageal cancer, Barrett’s esophagus, bladder cancer and pituitary tumors.

In the field of Gynecology, photomedicine is a fairly new method. Preliminary studies have been done in certain areas like vulva and cervical neoplasm, intraperitoneal ovarian metastasis and some begin diseases like endometriosis and menorrhagia.

Clinical Applications

• PUVA for the treatment of psoriasis
• Photodynamic therapy (PDT) for treatment of cancer and macular degeneration
• Gynecological Oncology
• Laser hair removal
• Optical diagnostics
• Confocal microscopy and fluorescence microscopy of in vivo tissue
• Diffuse reflectance spectroscopy for in vivo quantification of pigments (normal and cancerous), and hemoglobin.

External links

• Photodynamic Theory
  
• Photobiology Online
• European Society of Photobiology (ESP)
• American Society for Photobiology (ASP)
• Institute of Physical signs in Medicine
• The role of Photomedicine in Gynecological Oncology
• European Photochemistry Association (EPA)
• The National Radiological Protection Board (NRPB)
• Non-Ionising Radiation, Guy's and St Thomas' Hospital, UK
• European Light DOsimeter NETwork