By means of, or with regard to, photodynamics.

The study of the activating effects of light on living organisms

of, relating to, or caused by the energy or momentum of light or other electromagnetic radiations / of, or relating to photodynamics

Relating to photodynamics.

(medicine) A treatment for some forms of cancer and some skin disorders, involving the use of photosensitive chemicals, and controlled and directed laser beams.

plural of photodynamic therapy