Multiphysics Modeling for Radiofrequency ablation (RFA)

Radiofrequency ablation (RFA) of non-resectable tumors has been shown to be as effective as surgical resection. During an RFA procedure, the tumor is heated to a temperature sufficient to cause cell death; the RF current is used to heat the tissue and there is no clinically significant electrical interaction within the tissue.


While the intent of thermal therapy is to kill tumor cells, extra-cellular proteins will also be heated and can be denatured leading to permanent damage to the tissue infra-structure including vital structures such as blood vessels, nerves, ducts, etc.. Cooling by blood flow can also impede the killing of tumor cells near a blood vessel and it has been reported that a tumor of perivascular tissue remains viable near vessels greater than 3 mm diameter after RF therapy due to this “heat sink” effect.


Electroporation of tissue has been studied for over 50 years. It is now well known that an external electric field can change the permeability of the cell membrane to molecules, enabling the molecules to flow into the cytoplasm. It is also well known that increasing the electric field in-situ can cause irreversible cell damage leading to cell death without substantially raising the temperature of the tissue. Recently, it has been suggested that irreversible electroporation (IRE) could be a useful alternative to thermal therapies as a method of tumor ablation. Theoretically, non-thermal IRE has some advantages over thermal therapies by eliminating the aforementioned morbidities and the heat sink effect.


More than a single pulse is required to cause cell death with IRE and increasing the number of pulses applies more energy to the tissue, eventually causing heating. A characteristic difference between the RFA waveform and the IRE waveform is that RFA is a true alternating current (AC) waveform while IRE is a monophasic waveform. However, both can cause Joule heating from the conduction current therefore one must pay attention to the total energy.


In this study we examined histopathological tissue changes induced by short pulse/high voltage irreversible electroporation and used finite element modeling (FEM) to correlate the experimental results to electric field and temperature history. The model calculates tissue temperatures and voltage thresholds for operating parameters and geometry. The histology photographs demonstrate the experimental results under the same conditions. Matching the model to the experimental results allows us to understand the type of damage resulting from the electric field threshold and thermal history within each zone.

Click here for the full article.


COMSOL Training: Student Testimonial

We held another Solving COMSOL Multiphysics class last week. Nine participants pursuing engineering excellence worked through the four-day course, and left Friday equipped to apply and interact with all the key features of COMSOL Multiphysics® Software. They learned how to use the software to build geometry, apply their physics, develop approximate meshes, use solvers and post process results. That is a full four days! With all that information being shared over four days, we look forward to our follow up session in two weeks where we can answer questions that have arisen since the training.This testimonial from one of our students:


“I thought I got to work on some pretty cool projects using COMSOL until I got here. I took one look at the pictures AltaSim had in their training room, and I knew right away they were going to take me to the next level. I can’t believe I got to learn from them. At first I thought it would be too overwhelming, but Josh and Luke and Sergei, along with all the practice problems, made it understandable. I can’t wait to get back to the office and apply all of this knowing they are available if I get stuck.”


When we started offering training classes as Certified COMSOL Consultants, our goal was that each student would leave our classes fully equipped and wouldn’t feel like he or she was going back to the office to figure it out alone. We believe our customers should be as independent from the need for our consulting services as they choose to be. The Solving COMSOL Multiphysics class is just one that we offer. To learn more about our COMSOL classes, visit our training page.


Project Lead The Way

One of the practices we believe in here at AltaSim Technologies is continued education. Thanks to some good people at Thomas Worthington High School in Worthington, Ohio, we had a chance to go back to school repeatedly over the last 2 years. Well, actually “school” showed up at our door when several students contacted us about a project they were working on through PLTW – Project Lead the Way. PLTW is considered Ohio’s Premier STEM Program, and both the high schools and middle schools in Worthington School District take this program seriously.


“As students enter our capstone course their senior year, they must find real world experts to help them solve real world problems. This is where AltaSim comes in. AltaSim has been very helpful and accommodating. They approached our students with dignity and respect. It was great how they walked us through a design process with little assignments the students needed to complete along the way.” (Bryan Brown, PLTW Instructor at Thomas Worthington HS)


Helping these committed students think through their project was a great reminder that tomorrow’s product innovators and technology leaders are with us today. Not only did these young people think of how to create and build a “step ladder for the elderly,” but they also demonstrated their ability (& willingness) to think outside of themselves for the good of others. It is our belief that we found some of tomorrow’s industry leaders.


We can all learn from the example that the students of Thomas Worthington High School have shown us. While it was a real honor for us to be involved with these students, it is not our belief that we were “giving back” but rather “giving forward.” Per our Mission Statement: “We harness tomorrow’s technology to enable our customers to capture today’s markets.” Embedded in this statement is a commitment to:


  1. Provide lasting value to our customers
  2. Apply technology to enhance the capabilities of our customers
  3. Continue to make an ongoing technical contribution to society

SpaceClaim-COMSOL Webinar, April 10, 2013

In our “Breaking Traditions” entry, we mentioned the real life introduction to SpaceClaim that we received from COMSOL during the 2011 COMSOL Conference. Our solid model building has consumed less of our time and allowed us to focus on better analyses ever since. As is our commitment to our customers and the entire industry, when we make a discovery like this, we want to share it. We believe CAE can drive product development by optimizing models before CAD and validating results post-CAD.


That being said, on April 10, 2013 from 2:00-2:30 PM EST, we will be hosting a SpaceClaim-COMSOL webinar in which participants can actually learn how to use SpaceClaim to prepare models for analysis, as we have been doing. For those that are COMSOL users, SpaceClaim also has a LiveLink™. This from COMSOL’s website:


“LiveLink™ for the SpaceClaim® CAD system brings you the fusion of direct-modeling and multiphysics simulation in a tightly integrated environment, enabling optimal designs and collaboration across CAD and CAE teams.”


It is our experience that this 30 minute Webinar could return so much time that your projects get done faster with less energy and costs expended resulting in a healthier bottom-line. To register for this FREE Webinar, click here. You will automatically receive the Webinar access codes to confirm your participation once you register.


And if you have already been using SpaceClaim, we would love to hear of your success stories.