THE EFFECT OF MAGNETIC ABRASIVE FINISHING ON THE NEEDLE INNER FRICTION FORCE AND BIOPSY LENGTH

摘要

Increasing biopsy length could reduce the false negative rate in prostate biopsy diagnosis. In this paper, the effect of magnetic abrasive finishing (MAF) of needle inner surface on inner friction force and biopsy length was investigated. The test was conducted using the tissue-mimicking material polyvinyl chloride (PVC) and chicken breast. The inner friction forces of MAF-polished and unpolished needles were measured. In the PVC phantom, the smoothly polished needle had lowest inner friction force (0.0024 N/mm) and longest biopsy sample (34.3 mm). Although the roughly polished needle had a smoother surface than the unpolished needle, the significance of the effects on the biopsy performance due to the slight improvement of the needle surface was not observed. The biopsy tests with chicken breast tissue showed the trends similar to the case with PVC phantom. The smoothly polished needle had the smallest inner friction force (0.024 N/mm) and the longest biopsy sample (9.6 mm). These results showed that lowering the friction force between the needle and tissue facilitates the sliding of tissue along the needle, leading to a long biopsy sample. MAF can reduce the friction at the needle-tissue interface and obtaining longer biopsy samples.