Research on Mechanical Properties of Bevel-Tip Needle Based on Image Guidance

The flexible needle is a minimally invasive medical device mainly used for human biopsy. The insertion operation has a small wound, which is conducive to the rehabilitation of patients and has a good application prospect. However, the force of the flexibility on the tissue is not certain, which seriously affects the doctor's judgment of the injury caused by the needle insert to the patient. In this paper, the mechanical properties of the flexible needle are studied by image analysis, the mechanical model between the needle holder and the force sensor is established, and the force of the needle holder is calculated by the force sensor data. Based on the cantilever beam model, the cutting force of the needle tip to the soft tissue and the friction force of the needle body are analyzed by using the force of the needle holder. The mechanical properties of flexible needles and the damage to tissues caused by needle insertion have been studied. Finally, the deflection of the needle body is calculated using the experimental force data, which are compared with the analysis by the image processing system. The results show that the cantilever beam model can predict the force of the needle body more accurately, and then predict the insertion trajectory.