Nonlinear ultrasound parameter to monitor cell death in cancer cell samples

A scaling subtraction method was proposed to analyze the radio frequency data from cancer cell samples exposed to an anti-cancer drug and to estimate a nonlinear parameter. The nonlinear parameter was found to be well correlated (R2¼0.62) to the percentage of dead cells in apoptosis and necrosis. The origin of the nonlinearity may be related to a change in contacts between cells, since the nonlinear param- eter was well correlated to the average total coordination number of binary packings (R2?0.77). These results suggest that the scaling sub- traction method may be used to early quantify chemotherapeutic treat- ment efficiency.