Is there a reason for photodynamic therapy to not cause cancer if mobile phones might? I don't want to open a debate about whether cell phones can cause cancer,
I read the thread: Could cell-phone radiation cause cancer?
For the sake of this question let's assume there's a chance for cell-phones
to increase chances of cancer
Now, visible light is higher frequency and higher energy radiation than mobile phones,
You can take a look at the spectrum of elctromagnetic radiation: http://en.wikipedia.org/wiki/File:EM_spectrum.svg
I'm thinking of going to photodynamic therapy (it's a form of treatment that uses intense visible light for skin conditions - including acne)
Now, if visible light is higher frequency & higher energy than radio
waves, is there a reason that this kind of treatment would not raise
risk of cancer if cell-phones might?
these are some specifics about the light used (it is blue light):
Blue Intensity: 26273.0 uW/cm2 
Blue Peak Wavelength: 415.20 nm
Thanx a lot to anyone giving thought to this question.
 A: There is also no reason to correlate cell phone "radiation" to blue laser "radiation" - just because they are both electro-magnetic.
ps. 26273.0 uW/cm2 is 260W/m^2, if you go outside you receive about 1300 W/m^2 from the big nuclear reaction in the sky so I wouldn't be too convinced about the effectiveness of the  "intense blue light" therapy
Edit:
The danger from a source depends on the wavelength (how the electromagnetic radiation interacts with your body) and the power level ( how much of it is there ).
A cell phone uses low energy microwaves which don't interact strongly with your body so there is very little chance of them having any effect. In addition the power of a cell phone is tiny - 0.01% of the power of a microwave oven.
Blue light is potentially more harmful if it has enough energy (depending how blue) to affect chemical bonds. Ultraviolet (very blue) light has enough energy to break molecules apart and so can be dangers, which is why you get sunburn. Light of longer wavelengths can only damage you by the heating effect so you need a lot more light to cause any harm.  So the infrared light from your stove doesn't harm you, but an industrial cutting laser at the same wavelength can cut you in half.
I don't know what wavelength the 'therapy' uses, but if it is ultraviolet then a small amount of power could be harmful (ie sunburn), if it is visible blue then they would need to have very high levels of power to do any harm - by simply cooking you (like cell phones!).
Of course if the light is too long a wavelength and too low a power to have any effect on you - then exactly what is the point of the treatment?
A: There is no way to answer this question, because nobody has ever proposed a plausible mechanism by which cell phones could cause cancer. In fact, cell phones don't cause cancer. We know they don't cause cancer because (1) there is no plausible mechanism, (2) studies in humans that claim a non-null result don't show a dose-response, and (3) animal studies show no effects.
The reason frequency would be relevant would be that photons above a certain frequency are ionizing. For frequencies too low to be ionizing, there is no particular reason to believe that higher frequencies would be more harmful. Without a physical mechanism, there is simply no scientific way to approach this question.
