1. 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Sample withdrawn by vacuum pump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 gauge needle
( 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 gauge
1. Actuator
Future Work
Test on real (non-human) tissue and evaluate sample yield with pathologist
Replace function generator with 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.
< April 30, 2007.
2. Fine Needle Aspiration Biopsy of the Thyroid Gland Mayo Foundation
< March 5, 2007.
Suen, K. “Fine Needle Aspiration Biopsy of the Thyroid”. Canadian Medical Association
Journal: September 2002,( ). April 30, 2007.
4. Tao Aspirator Tao & Tao Technology, Inc. <
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.