A method for determining a suitable set of parameters for operating a light source within a photo-thermal targeted treatment system for targeting a chromophore embedded in a medium is disclosed. The method includes, before administration of a treatment protocol: 1) administering at least one laser pulse from the light source at a preset power level to a location to be treated, the preset power level being below a known damage threshold; 2) measuring a skin surface temperature at the location to be treated, following administration of the at least one laser pulse; 3) estimating a relationship between the parameters for operating the light source and the skin surface temperature; and 4) defining a safe operating range for the parameters for operating the light source in order to avoid thermal damage to the medium at the location to be treated while still effectively targeting the chromophore in administering the treatment protocol.