Thursday, April 2, 2009
By Sarah Petrie

Above, from left: Kamran Ahrar, M.D., and R. Jason Stafford, Ph.D., discuss an upcoming spinal surgery that will use the Visualase technology. They’ll be able to watch the tumor (ablate) in near real time during the procedure. Depending on where the tumor is located, the patient may or may not be awake during the procedure.

History books show that surgeons began removing cancerous tumors as early as the second century. Zoom ahead to 2009, take away the scalpels, scars and side effects that typically accompany surgery, and trade them for a tiny laser beam… It sounds like science fiction, but our researchers and clinicians are among the first in the nation to investigate a new procedure that does just this … and more.

“It’s called laser-induced thermal therapy, and the basic theory is that the laser heats the tumor to a certain temperature to (ablate) it,” explains Jeffrey Weinberg, M.D., associate professor in Neurosurgery, who’s conducting a clinical trial to test the effectiveness of this procedure on patients with metastatic brain tumors.
How hot is too hot for a cancerous tumor? Sixty degrees Celsius, in most cases.

“The clinical trial targets patients with otherwise inoperable tumors or those for whom other treatments failed,” Weinberg says.

Delivering laser energy using a device only millimeters in diameter, the procedure leaves a scar no bigger than your thumb. Plus, there should be no side effects for this less-invasive surgery, which takes only a few hours from start to finish. “The laser portion should only take a few minutes, and patients will experience no swelling and little pain,” Weinberg adds.

Other forms of what also is known as ablation therapy already are in practice, (ablating) tumors using heat, cold or electricity. So what makes this particular procedure so revolutionary? The physician actually watches the tumor (ablation) in real time, according to Kamran Ahrar, M.D., associate professor in Interventional Radiology, who has performed the procedure on a few patients with bone and spinal tumors as part of a similar clinical trial.

Weinberg agrees this is the biggest advantage of this method over other forms of treatment. “Patients don’t have to wait weeks or months for tests to confirm if the entire tumor is gone, as is the case with most surgeries. Instead, using this technology, we can convert magnetic resonance imaging into a color picture that indicates the temperature of the tissue,” he says. “This allows us to know exactly when the tumor is hot enough to fully die.”

How does it work?

Houston-based company Visualase Inc., which sells the technology, approached M. D. Anderson in 2000 for help with developing the tool. “For this procedure to be successful, the doctors must know the precise location and distribution of temperature in the tumor and that’s where the physicists come in the picture,” explains R. Jason Stafford, Ph.D., assistant professor in Imaging Physics, and lead consultant on the Visualase technology development for M. D. Anderson.

In other words, a stereotactic navigation system, “like a GPS for your brain” as Weinberg puts it, pinpoints the exact location and size of the tumor. After the surgeon drills a hole and sends the specially designed fiber directly to the tumor, the laser is activated, thus heating the tumor. Doing it in the MRI allows clinicians to monitor temperatures within the tissue. “Temperature as well as predicted regions of complete treatment are color-coded on a screen, giving us the ability to adjust or retreat a certain area, as needed,” Stafford adds.

And at M. D. Anderson, this entire procedure can be performed in one room, unlike at other institutions that also are researching the procedure. We have a dedicated intra-operative MRI suite, which is safer for patients than moving them to different locations to complete the procedure.

Click here to view the embedded video.

“Lasers used in keyhole surgery in brain” – Agence France-Presse

Paris, France August 29th, 2008 – Visualase technology used successfully in brain tumors, as reported by AFP and the Telegraph (UK).

AFP | Telegraph

Paris hospital hosts pioneering laser brain surgery

Saturday 30 August 2008 – A French team of neurosurgeons claims top have successfully tested a combination of new techniques, including fibre-optic lasers.

France24