Computer-aided Patient Specific Treatment Planning Of Cryosurgery For Breast Cancer

Abstract

Cryosurgery, which is to destroy tumors by use of localized freezing, is an emerging treatment modality for breast cancer as the size of detectable tumor becomes smaller due to more frequent use of various diagnostic imaging including MRI, CT and mammogram. Although general surgical guideline has been developed and its effectiveness has been demonstrated, cryosurgical protocol should be adjusted for a given patient to accommodate patient-specific variations including tumor size, location and geometry of patient's breast. In this study, a computerized treatment planning tool was developed to aid surgeons to determine surgical parameters considering patient specific diagnostic information. This tool consists of three modules - 1) three dimensional reconstruction of diagnostic images, 2) numerical simulation of cryosurgical procedure, and 3) prediction of the treatment outcome. Three dimensional image reconstruction was performed by digitizing two patient specific diagnostic images perpendicular to each other, importing the digitized key points of the images into a commercial finite element analysis software (ANSYS), and constructing three dimensional volume. With a given surgical parameter, the numerical simulation module performed three dimensional transient thermal analysis of a cryosurgical procedure. Using the results of thermal analysis, the extent of cryodesturction was predicted through an empirical correlation for cryoinjury of human breast cancer cells. By iteratively using the developed modules, the surgical parameters can be determined for optimum treatment outcome.