Device Specifications Device to Improve Diagnostic Yield of Fine Needle Aspiration Jason Tham, Tu Hoang Anh Mai, Robyn Hrobsky, Aaron Freis Client: Dr. Frederick Kelcz, Department of Radiology, University of Wisconsin Hospital Advisor: Professor Naomi Chesler, Department of Biomedical Engineering, University of Wisconsin Abstract Device Specifications Testing and Results Reusable up to 1 year • User-friendly to physician demographic • Dependable and precise • Variable needle stroke (2-15 mm) • Variable frequencies (0-9 Hz) • Automated vacuum mechanism Square wave applied to pneumatic relay Tested with pressure from 40 to 60 PSI Needle stroke varied from 2.5 to 15 mm Maximum operational frequency investigated for load, no-load conditions Phantom: “tumor” (olive) suspended in firm agar gel Sample withdrawn by vacuum pump Sample volume will be measured The purpose of this project is to improve the current procedure for Fine Needle Aspiration. Our client wants to automate the procedure using a handheld oscillation device. The device must be safe, have an adjustable stroke and frequency, and be ergonomic. We designed and constructed a prototype using a pneumatic drive system with a vacuum pump for suction. Phantom tissue testing has commenced with future intention of human tissue testing. Final Design Design selected based on adjustability, repeatability and ergonomic advantages CPVC encasement holds pneumatic actuator Pneumatic actuator oscillates needle Actuator frequency controlled electronically Stroke length (0-15mm) controlled by slide Actuator power supplied by regulated pressure source (0-60 PSI) Piston pump provides vacuum to needle Background Fine Needle Aspiration is a biopsy method of collecting samples Uses 21-25 gauge needle (.813-.513 mm diameter) Manual hand procedure requires repetitive, low yield sampling for diagnosis Figure 6. Graph of Maximum Operating Frequency vs. Stroke Length 3. Stopper slide 2. Stopcock connected to vacuum pump 4. Pressure to actuator and exhaust 5. CPVC encasement 6. Fine needle 22-25 gauge 1. Actuator Future Work Test on real (non-human) tissue and evaluate sample yield with pathologist Replace function generator with 5-5-5 timer Include vibration motor Redesign stopcock holder for multiple uses Reliability, repeatability, and efficacy testing with human tissue Figure 1. FNA procedure of breast tissue [1] Figure 2. FNA procedure of thyroid tissue [3] References Competition 1. “Fine Needle Aspiration”. Medax Medical Devices: 2005. <http://www.medaxmedical.com>. April 30, 2007. 2. Fine Needle Aspiration Biopsy of the Thyroid Gland. 2005 Mayo Foundation <http://www.thyroidmanager.org> March 5, 2007. Suen, K. “Fine Needle Aspiration Biopsy of the Thyroid”. Canadian Medical Association Journal: September 2002,(491-495). April 30, 2007. 4. Tao Aspirator. 2001 Tao & Tao Technology, Inc. <http://www.taoaspirator.com> March 5, 2007. Acknowledgements Figure 3. Tao Aspirator [4] Figure 4. Cameco Syringe Gun [2] Professor Frank Fronczak, Dr. Robert Tham, Chris Goplen, University of Wisconsin Hospital, University of Wisconsin-Department of Biomedical Engineering, College of Engineering Student Shop Personnel. Figure 5. Final design.