TY - JOUR
T1 - Novel needle cutting edge geometry for end-cut biopsy
AU - Moore, Jason Z.
AU - McLaughlin, Patrick W.
AU - Shih, Albert J.
N1 - Funding Information:
This research work is sponsored by the National Science Foundation (NSF) Award CMMI#0825795, National Natural Science Foundation of China (Award No. 50775119), and supported by the University of Michigan Radiation Oncology Department. FIG. 1. End-cut needle biopsy procedure of capturing tissue. FIG. 2. Definitions of inclination angle (λ) and rake angle (α) on a two-plane symmetric needle tip. FIG. 3. Regular two-plane symmetric needle defined by the bevel angle ξ. FIG. 4. Inclination (λ) and rake angle (α) of regular two-plane symmetric needle and ECE two-plane needle. FIG. 5. (a) ECE two-plane needle with a continuous cutting edge and (b) ECE two-plane needle with a discontinuous cutting edge. FIG. 6. ECE two-plane needle in (a) isometric view (b) side view, and (c) top view. FIG. 7. (a) Side view and (b) top view of needle tip exposed to initial tissue cutting. FIG. 8. Experimental setup for needle insertion into bovine liver. FIG. 9. Regular two-plane symmetric and ECE needles used for experiments. FIG. 10. Needle insertion into bovine liver force example of ECE needle with ξ = 20°. FIG. 11. Biopsy sample length comparing ECE two-plane needles to regular two-plane needles. FIG. 12. Biopsy sample length comparing pressure effect for (a) regular and (b) ECE two-plane needles. FIG. 13. Internal wall friction force repels the motion of the incoming tissue while the vacuum force helps to pull the sample into the needle. FIG. 14. Needle insertion force comparing ECE two-plane needles to regular two-plane needles. FIG. 15. Needle insertion force comparing pressure effect for (a) regular and (b) ECE two-plane needles. FIG. 16. Force model prediction with given S factors for regular two-plane and ECE needles. FIG. 17. The effect of needle vacuum pressure on S factor. FIG. 18. Needle insertion force compared to biopsy length with least squares best fit lines for needle pressures of (a) 0 kPa, (b) −33.9 kPa, and (c) −67.7 kPa.
PY - 2012/1
Y1 - 2012/1
N2 - Purpose: To introduce and determine the biopsy length performance of the novel enhanced cutting edge (ECE) needle tip design, which contains high inclination angles that allow for more efficient tissue cutting. Methods: ECE and regular two-plane symmetric needle tip's biopsy performance and cutting force are compared over a series of needle insertion experiments into bovine liver under varying levels of internal needle vacuum. An earlier developed needle tip force model is also applied. From these experiments and force model, the effect of needle tip geometry and vacuum on biopsy performance and force is studied. Results: Biopsy sample length is on average 22%, 30%, and 49% longer for ECE needles compared to that of regular needles for the internal pressures of 0, -33.9, and -67.7 kPa, respectively. For ECE needles the vacuum level of -67.7 kPa produces on average biopsy lengths that are 41%, 31%, 29%, 45%, and 42% longer compared to no vacuum for two-plane needle tip bevel angles of 10°, 15°, 20°, 25°, and 30°, respectively. The force results show the ECE needle can be inserted with less initial insertion force than the regular two-plane needle for needles where the needle tip is fully contacting the tissue upon insertion. Vacuum is also showed to help lower insertion forces. Conclusions: The novel ECE needle tip design outperforms the regular two-plane symmetric needle by yielding longer biopsy samples and lower insertion forces, thereby demonstrating the benefits of needle geometries that contain higher inclination angles. The use of vacuum further improves the ECE needle tip biopsy sample length and lowers insertion forces.
AB - Purpose: To introduce and determine the biopsy length performance of the novel enhanced cutting edge (ECE) needle tip design, which contains high inclination angles that allow for more efficient tissue cutting. Methods: ECE and regular two-plane symmetric needle tip's biopsy performance and cutting force are compared over a series of needle insertion experiments into bovine liver under varying levels of internal needle vacuum. An earlier developed needle tip force model is also applied. From these experiments and force model, the effect of needle tip geometry and vacuum on biopsy performance and force is studied. Results: Biopsy sample length is on average 22%, 30%, and 49% longer for ECE needles compared to that of regular needles for the internal pressures of 0, -33.9, and -67.7 kPa, respectively. For ECE needles the vacuum level of -67.7 kPa produces on average biopsy lengths that are 41%, 31%, 29%, 45%, and 42% longer compared to no vacuum for two-plane needle tip bevel angles of 10°, 15°, 20°, 25°, and 30°, respectively. The force results show the ECE needle can be inserted with less initial insertion force than the regular two-plane needle for needles where the needle tip is fully contacting the tissue upon insertion. Vacuum is also showed to help lower insertion forces. Conclusions: The novel ECE needle tip design outperforms the regular two-plane symmetric needle by yielding longer biopsy samples and lower insertion forces, thereby demonstrating the benefits of needle geometries that contain higher inclination angles. The use of vacuum further improves the ECE needle tip biopsy sample length and lowers insertion forces.
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U2 - 10.1118/1.3665253
DO - 10.1118/1.3665253
M3 - Article
C2 - 22225279
AN - SCOPUS:84855468665
SN - 0094-2405
VL - 39
SP - 99
EP - 108
JO - Medical Physics
JF - Medical Physics
IS - 1
ER -