Archived: Using Graphical System Design for Tumor Treatment

Jeff Stevens, Sanarus

NI played a fundamental part in achieving our goals. Our product design, prototype, and eventual deployment timelines were met because of the graphical system design platform from NI.

- Jeff Stevens, Sanarus



The Challenge:

Designing, prototyping, and deploying the user interface and control system for an FDA–approved, Class II medical device used to treat breast tumors in a less invasive and nearly painless procedure while maintaining the design process within strict regulatory guidelines.

The Solution:

Using the NI CompactRIO platform, NI LabVIEW Real-Time, and the LabVIEW FPGA Module to develop a flexible and reliable GUI and control system under extreme time-to-market pressure to deliver a device that would dramatically reduce the emotional and physical discomfort of patients undergoing tumor treatment.

At Sanarus, a medical device start-up company, we developed plans for a potentially revolutionary product that could change the way doctors treat benign tumors. With this device, doctors can eliminate tumors by freezing and killing them in an almost painless outpatient procedure, a dramatic change from the inpatient surgical solution or the “wait-and-see” approach used previously. With a well-executed design and development plan, we hoped to market a device that would have a huge impact on breast cancer treatment.


The end result, the Visica2 Treatment System (V2), is an instrument intended for use in a doctor’s office or clinic. The procedure involves local anesthesia and a real-time, ultrasound-guided approach that is virtually painless. The treatment, which lasts 10 to 20 minutes, freezes and destroys targeted tissue through an incision so small that it does not require stitches.


Time to Market Pressure

We were tasked with developing a working prototype of the V2 system within four months to satisfy the product release schedule. In addition to fulfilling our commitment to our investors, we needed to meet marketplace demand and produce the V2 as soon as possible.

Writing firmware and designing a custom circuit board for the device would have been time-consuming, and any error at the firmware or software level could have created delays that would have threatened the entire project. Because V2 is a medical device, it must not have any software or firmware errors that could compromise system performance. If the device had failed the exhaustive testing required for our 510(k) submission, our entire project would have failed and the V2 would not have made it to market. Based on these requirements, we needed an extremely reliable development option for V2.


Speeding Development with Off-the-Shelf Hardware

Sanarus invited a National Instruments field engineer to discuss possible solutions with us. We quickly realized that the CompactRIO was a viable solution for our needs because of its mix of programmability and integrated I/O development. We designed the prototype using CompactRIO to prove that the V2 would be developed reliably in a short period of time. A trade-off table illustrated the differences between using a CompactRIO system and our own custom hardware. The payoff from using CompactRIO was apparent; while a custom solution would have taken months to develop, the NI solution took only weeks.


In addition, with custom firmware, “late game” changes would have required new and difficult revisions, but with the CompactRIO platform, we could revise our code if needed with minimal effort. When we decided that the UI needed to be a touch panel PC instead of buttons and LEDs, we used the LabVIEW for Windows graphical programming environment to develop a UI for a PanelPC. We were able to simply manage communications between the GUI and the CompactRIO real-time controller using LabVIEW shared variables. We also met the new feature requests without causing delays in the development schedule because of the system flexibility.


We knew CompactRIO would pass EMC certification, because NI precertified the modules. This guaranteed that our prototype would not have to be redesigned if it failed EMC certification.


The final V2 system consists of a PanelPC that runs LabVIEW for Windows. This operates the user interface and sends commands to a CompactRIO system using LabVIEW Shared Variables. LabVIEW Real-Time was used to implement a state machine on the CompactRIO real-time controller, and on the PID, LabVIEW Real-Time regulated loops to control the temperature of the tip of the probe. This is done by providing control algorithms to a liquid nitrogen pump for cooling as well as a simple resistive heating element. The LabVIEW FPGA was used to manage the interfacing to the I/O signals necessary to control these devices.


In long-term studies, our technique is highly effective in destroying common tumors, and the V2 is now available at selected centers throughout the U.S. Thanks to NI, we quickly and efficiently developed an embedded control system with a user-friendly GUI for the V2 while maintaining the highest quality, and ultimately, ensuring the safety of our customers’ patients.


NI played a fundamental part in achieving our goals. Our product design, prototype, and eventual deployment timelines were met because of the graphical system design platform from NI.


With LabVIEW, we designed and coded our controller in house, then prototyped and deployed machines much quicker than we ever thought possible. In fact, our CEO called CompactRIO a key factor in the success of the Visica2 Treatment System project.


Author Information:

Jeff Stevens