Any electromagnetic radiation can be described using radiometric units. These units describe the energy or power that is either emitted from a source or that arrives at a surface.
Photometric units are useable ONLY for visible radiation.
While photometric units are often used in the lighting and photographic industry, where the response of the human eye is of importance, photometric units are not generally the most appropriate units to completely describe radiation used in scientific studies. The recommended radiometric SI units are the following. D.P. Valenzeno and M. Tarr in Oxygen Free Radicals in Tissue Damage , Eds. M. Tarr and F.E. Samson, Birkhauser Boston, pp. L.I. Grossweiner in The Science of Photobiology , Ed.