Fundamental Study of Laser Photoactivation for Cancer Therapy

Abstract

In an attempt to define the applicability of photoactivation therapy for cancer, the efficacy of therapy bad been studied using a tumor cell line (HeLa Ohio).
The light source were an argon laser (488, 514.5nm) and a krypton ion laser (647.1nm), Drugs tested were hematoporphyrin derivative (HpD) and Protoporphyrin disodium (PPNa) To investigate cytocidal ettects by laser irradiation with these drugs, the%⁵¹ Cr release was studied.
The %⁵¹ Cr release were less than 0.1% in laser irradiation only (60J/cm²), 49.2% in laser irradiation (at 514.5nm) with HpD (100μg/me) and 55.3%in laser irradiation (at 514.5nm) with PPNa (100μg/me)
The results revealed that laser irradiation only had no cytocidal ettect. while both of HpD d PPNa had intense cytocidal ettect.
Futhermore, these cytocidal ettects were strongly influenced by the changes of wave length
The most effective wavelength for laser irradiation with HpD or PPNa were 514.5nm.
These results showed that the photoactivation therapy with HpD may be more effective by the laser irradiation at 514.5nm, and from the intense cytocidal effects of laser irradiation with PPNa, PPNa may be effective as a new photosensitizer.