Photomedicine 

A brand of medicine

Photomedicine is a 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.

Dr. Searles employs a variety of phototherapies in the management of many skin conditions. 

Ultraviolet Phototherapy

UV radiation is known to modify the immune system and reduce inflammatory responses. Light therapy for skin conditions like psoriasis or eczema use UVA (315-400 nm wavelength) or UVB (280-315 nm wavelength) light waves. UVA, combined with a drug taken orally, is known as PUVA treatment. However, PUVA therapy is no longer available due to the unavailability of psoralens.  Narrow band UVB is the 311 nm wavelength and is given as a light therapy treatment rather than full spectrum UVB.  The light therapy can be delivered to the whole body, or with a smaller unit designed for use with the hands and feet.  Two treatments per week are usually required.  

Photodynamic Therapy

Photodynamic therapy (PDT) is a medical treatment that uses a photosensitizing drug (a drug that becomes activated by light exposure) and a light source to activate the applied drug. The result is an activated oxygen molecule that can destroy nearby cells. Precancerous cells and certain types of cancer cells can be treated this way. The procedure is easily performed in a physician's office or outpatient setting.

PDT essentially has three steps. First, a light-sensitizing liquid or cream is applied or administered. Second, there is an incubation period of minutes to hours. Finally, the target tissue is then exposed to a specific wavelength of light that then activates the photosensitizing medication.

Steps:

  • application of photosensitizer drug
  • incubation period
  • light activation


Although first used in the early 1900s, PDT in the modern sense is a fairly new, evolving science. Current PDT involves a variety of incubation times for the light-sensitizing drug and a variety of light sources depending on the target tissue. The basic premise of PDT is selective tissue destruction. Although the photosensitizer may be absorbed all over by many cells, atypical or cancerous cells take up more of the drug and retain the drug for a longer duration than normal tissues.

PDT is currently used in a number of medical fields including oncology (cancer), dermatology (skin), and cosmetic surgery.

In dermatology, PDT with the photosensitizer Metvix® (20% delta-aminolevulinic acid HCl) is used for the treatment of pre-skin cancers called actinic keratosis (AK). The initial approval was specifically for normal (non-hyperkeratotic) actinic keratosis of the face and scalp with a specified 3-hour drug incubation time, and about 9 minutes of activation by a red light source. PDT is also used for acne, rosacea, skin cancer, sun damage, cosmetic skin improvement, oily skin, enlarged sebaceous glands, wrinkles rejuvenation (anti-aging), warts, hidradenitis suppurativa, psoriasis, and many other skin conditions. It is not used to remove moles or birthmarks.

 

 Lasers

Lasers and other light technologies can be used for a wide variety of skin conditions.  Dr. Searles provides the following technologies:

  • Nd:YAG (1064 nm) laser for blood vessel lesions, hair reduction and Laser Genesis facial rejuvenation.
  • Intense Pulsed Light (IPL) therapy for treatment of blood vessels, pigmented lesions, and hair reduction
  • YSGG (2740 nm) laser for skin resurfacing.