SC, thank you for the very detailed response. By the that "excited Oxygen state" to the best of my knowledge, is not really a radical, but excited molecular oxygen, specifically delta singlet oxygen, an excited species with an average half life time of 40 seconds (or is it minutes?) (in vacuum, much shorter within tissues, of course).
When using selectively absorbed drugs activated with specific laser beams, I presume the practitioner must scan the spot over the area affected, how does he knows, where the beam has already impinged on the tissues and what parts of the retina still need be irradiated? Typically, the beam, as you stated is between .o5 to .5 mm while the target tissue must be much larger. I am also interested in the quantum yield for activation (namely, in essence, how many photons need be delivered before the activation process can be assumed to have taken place statistically everywhere).
Thanks again.
Zeev |
