An in Vivo Study on Evaluation of Early Relaxation Time in Breast Tissue

摘要

Treatment methods can be more effective once the mechanical behavior of the related tissues is identified through indentation tests. The main target of the present study is to characterize the viscoelastic behavior of breast tissue by measuring the relaxation time. To this end, an in-vivo study is conducted on 5 cases through applying indentation test with the help of a robot-assisted device. The tissue is loaded through a special protocol based on the Helsinki agreement and the force-displacement data is recorded in the unloading procedure. These data are fitted to a 5-element Wiechert model and two relaxation times are obtained. The smaller value which is called the early relaxation time shows noteworthy results. Results imply that there is considerable difference between the early relaxation time in the tumor-included points in comparison with the healthy regions as the greatest difference is found to be 7.08 s. Additionally, significant variation in the measured early relaxation times is observed between individuals which is the sign of structural variation of the breast tissue. The difference reaches to 10.94 s for some of the examined cases.