mainly through the induction of cell death. Distinct types of cell death may be elicited by different PDT
regimes. In this study, efforts are underway to optimize PDT protocols for improved efficacy and combination
of all three PDT mechanisms involved in the different human carcinomas cell narcosis. Our in vitro cell culture
experiments with 5-aminolevulanic acid (ALA) a clinically approved photiosensitizer (PS) and 635 nm laser
light have yielded promising results, as follow: (1) (human cervical cancer (HeLa) cell line incubated, for 18 h,
with 30
g/ml of 5-ALA, treated with laser light dose of 50 J/cm2 can produce 85% of cell killing (2) human larynx carcinoma (Hep2c) cell line incubated, for 7 h, with 55
g/ml of 5-ALA, treated with laser light dose of 85 J/cm2 can produce 75% of cell killing (3) human liver cancer (HepG2) cell line incubated, for 22–48 h, with
262
g/ml of 5-ALA, treated with laser light dose of 120 J/cm2 can produce 95% of cell killing (4) human mus-cle cancer (RD) cell line incubated, for 47 h, with 250
g/ml of 5-ALA, treated with laser light dose of 80 J/cm2 can produce 76% of cell killing (5) Human embryonic kidney (HEK293T) cell line incubated, for 18 h, with
400
g/ml of 5-ALA, treated with laser light dose of 40 J/cm2 can produce 82% of cell killing confirming the efficacy of photodynamic therapy.