Treating biological tissue can include selecting a parameter for electromagnetic radiation based on at least one parameter of a target region within the biological tissue. Treating biological tissue also includes methods, systems, and kits for delivering the electromagnetic radiation through a surface of the biological tissue to the target region to induce within the target region a sub-surface thermal injury characterized, for example, by a desired degree and a desired depth and confining the sub-surface thermal injury to substantially within the target region.
