Design of a Compliant Mechanism Radiofrequency Ablation Probe to Treat Pancreatic Carcinoma

Open Access
Kusiak, Benjamin Michael
Graduate Program:
Mechanical Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
Committee Members:
  • Mary I Frecker, Thesis Advisor
  • Radiofrequency Ablation
  • Pancreatic Carcinoma
  • Minimally Invasive
Pancreatic cancer is a deadly and difficult to treat disease affecting hundreds of thousands of patients globally every year. With difficult diagnosis and limited treatment options, the estimated five-year survival rate stands at a meager 5%. Radiofrequency ablation (RFA) is a recognized and well-established treatment option for other types of cancers such as hepatic and renal carcinomas, but is unsuitable in current form for the treatment of the pancreas. The goal of this research is to explore and model specially-shaped, deployable RFA probes introduced to the body via an endoscope. We propose a novel RFA probe, referred to as “the whisk design,” composed of superelastic nitinol to achieve adequate mechanical and ablative results. Modeling is pursued in two major areas. First, mechanical modeling is pursued in ANSYS to determine the stress tolerance of the proposed design. The device is expected to undergo high amounts of stress prior to the insertion phase of use; therefore a finite element model was developed for this stage. Since the device has default-open geometry, the free elongation models displace it to a closed diameter capable of passing through the endoscope’s working channel. The design was a success and experienced a maximum Von Mises stress of 445 MPa in the narrow regions of the tines. Secondly, the proposed design was analyzed for ablative potential utilizing the finite element software COMSOL. For these models, the interaction between an applied electric potential, temperature distribution, and necrosis zone (where cell death occurs) were studied. The model showed that the proposed device surpassed design goals in creating a necrosis zone of 3 centimeters with temperatures exceeding 50 °C. With finite element models completed successfully, alpha prototypes and design refinement can be performed in future studies.