“VGH wins prize for light therapy infection control”

Given my interest in light therapy, Google served this article up to me as relevant. It explains how Vancouver General Hospital received an international innovation award for infection control research using “light therapy”.

I was thrilled to see the title of the article but then instantly confused because the light shining in the kid’s nose is white. If it were light therapy for infection control, I thought, it should be blue light. Turns out this is another example of the confusion between light therapy and photodynamic therapy, or PDT.

To quote from the article, here is how their therapy works:

“Nasal photodisinfection involves applying a blue dye to the inside of a patient’s nose before surgery. The dye attaches itself to germs and when a light is shone inside, potentially “bad” bacteria are destroyed.”

What makes this photodynamic therapy and not light therapy is the use of the light sensitizing “blue dye” that was applied first. The bad bacteria absorb the dye. Then, when the light is shone on it, the light triggers a reaction in the dye and every cell that has absorbed it dies. That is the definition of PDT. In PDT the “active ingredient” is the dye. The light is just used to make it active. In light therapy, the “active ingredient” is the light, specifically the color, or wavelength of the light. Adding to the confusion, the dye they used in this case was blue.

Blue light therapy also kills bad bacteria, including the kind they would be trying to kill in this article, that being staph, and the antibiotic resistant variety, MRSA. Blue light kills these harmful bacteria all by itself, without the need for a photo-sensitizing agent, or dye.

PDT works too, and any method they can employ to stop the tide of deaths from hospital related infection is great, but calling it “light therapy” is not accurate and has seriously confused the issue for many.

In case, in the future, the above link to this original article does not work, try this one.