Question

A laser beam of spot size a = 1 mm^2 impinges on tissue. assume that tissue is mostly holding water.the water absorption coefficient of these laser is

Answer 1

A common use of medical lasers is to vaporize a tissue for the purpose of removing an obstruction or mass of unwanted tissue such a tumor or fibrous tissue. Some of the common lasers use for such a purpose are the continuous argon ion laser, Nd:YAG, and CO2 lasers. This article describes the basic dosimetry that predicts the rate of tissue removal by a continuous laser. This article does not consider tissue removal by pulsed lasers in the microsecond to nanosecond regime, which requires consideration of mechanical effects, or shorter sub-ns pulses which usually involve nonlinear absorption and plasma formation.

The basic idea is that tissue is mostly water and removing tissue is like boiling water. A gram of water requires a given amount of energy in order to be vaporized into gas. By calculating the amount of laser energy absorbed per unit area at the tissue surface, one can estimate the grams of water vaporized per unit time per unit area. It's all a matter of energy bookkeeping.

Answer 2

tissue is mostly holding water.the water absorption coefficient of these laser is