Photosensitized patients and operating lights

Abstract

Photosensitized patients who receive intra-operative photodynamic therapy are subjected to the intense brightness of operating lights. In order to investigate the potential phototoxic effects of this therapy, light energy densities were measured in non-photosensitized patients undergoing major abdominal surgery. The results show energy densities of 0.14 to 12.51 J cm−2 of polychromatic light for different operative fields. By a consideration of photon absorption numbers, these levels have a photodynamic equivalent of 0.34 to 30.06 J cm−2 of 630 nm light at the surface of tissue. If surgeons are unaware of the possible phototoxic effects of operating lights, some tissues could receive an unacceptably high energy density of polychromatic light. However, operating lights should not give significant phototoxic effects if the surgeon is aware and takes simple precautions.