Conventional frequency ultrasound detection of tumor response in vivo to cancer treatment administration

Current methods employed to evaluate patient response to cancer therapy are typically invasive requiring examination of excised tissue. The development of a non-invasive method of monitoring patient response to cancer therapy administration would potentiate clinical decisions permitting clinicians to adjust therapy regimens early in a treatment course based upon individual patient responses. It has been previously demonstrated that high frequency ultrasound is capable of reliably quantifying structural changes in tumor morphology in response to cancer therapies. Preliminary work has also indicated that ultrasound employed at clinically relevant frequencies (1-15 MHz) can detect apoptotic cell death using in vitro models. This thesis examines changes in tumor morphology in response to cancer therapy administration employing ultrasound at a clinically applicable frequency in a preclinical in vivo mouse model. The power spectrum of the radiofrequency data obtained from tumors was analyzed via linear regression spectroscopic analysis, as well as evaluating a statistical analysis of the amplitude distribution of the signal envelope. It is demonstrated here for the first time that 7 MHz ultrasound can detect apoptotic and other forms of cell death in vivo. A potential for a parametric imaging technique to visually represent analysis results is also demonstrated.