Apoptosis, induced in cancer cells by antitumor agents such as doxorubicin, dactinomycin, and the platinum drugs, is characterized by impaired respiration, decreased ATP, and activated caspase. To investigate the sensitivity of malignant cells to a variety of drug agents, quantitative measures of cytotoxicity under treatment of those drugs are employed. The mitochondrial oxygen consumptions are monitored by analyzing the phosphorescence decay rate of a palladium phosphor. Simultaneously, cellular ATP contents are detected through a bioluminescence system, and intracellular caspase activation...