The primary goal of my research focus is to develop image-guided, minimally invasive therapies for malignant disease with radiofrequency (RF) tissue ablation, a thermally-mediated method for inducing coagulation necrosis serving as the key core-enabling technology. A main focus of our investigation has been the use of RF ablation as a treatment for liver and other focal metastases. Over the last five years, we have extensively characterized the relationship between RF parameters and the resultant induced coagulation necrosis. In addition, we have reported several technical advances which have sequentially increased the achievable coagulation diameter from a single RF application to greater than 7 cm including: the use of multiprobe arrays, saline infusion, internally-cooled electrodes, pulsed-RF energy deposition, and the use of a cluster electrode system. Currently, we are attempting to determine clinical efficacy of this method for intrahepatic colorectal metastases in a prospective, multi-center trial.
We have also identified and studied biophysical factors such as tissue blood flow and tissue electrical conductivity which limit the extent of RF-induced coagulation necrosis in-vivo. We have demonstrated the relationship between increased blood flow and reduced coagulation, and have shown that reduction of blood flow by mechanical or pharmacologic methods can increase coagulation volume. Additionally, we are studying and characterizing new diagnostic imaging methods for determining the extent of induced coagulation necrosis using ultrasound with microbubble contrast agents, contrast-enhanced dynamic CT, and MR imaging.
We are further attempting to couple RF delivery to other emerging technologies. For example, we have applied RF to metallic stents as a method for inducing transluminal coagulation necrosis, and are currently studying the utility of applying RF to the pancreas and other visceral organs using endoscopic ultrasonography with modified RF electrodes.