Patient-specific visco-hyperelastic mechanical model for breast tumor localization in surgical planning

Breast-conserving surgery is typically performed with the patient in a supine position, whereas preoperative diagnostic MRI breast images are obtained with the patient in a prone position. The change in patient positioning causes significant large deformations, requiring preoperative localization of the detected lesions. Developing an individual-specific breast biomechanical model capable of simulating these deformations remains challenging yet highly desirable. This study presents a novel approach that combines finite element analysis with the optimization of mechanical properties of breast tissues, using only surface information to construct a personalized deformation model of the breast. A visco-hyperelastic model is employed to characterize the stress-strain relationship of breast tissue. The proposed method has been tested on 15 cases of breast cancer and achieves a tumor localization error of 8.12 ± 4.15 mm. The results show that this approach provides an accurate and realistic estimation of large breast tissue deformations and yields smaller tumor localization errors compared to previously reported methods.