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New technology helps minimize radiation risk

March 30, 2010 7:14:55 PM PDT
The Food and Drug Administration is holding hearings in Washington this week about the levels of radiation patients are being exposed to from powerful new imaging technologies used in many hospitals -- particularly CT-scans and flouroscopy. However, cardiac surgeons at Stanford are working with one new technology that could actually reduce the amount of radiation used in certain procedures.

Dave, who asked us not to use his last name, suffers from an irregular heartbeat, a condition known as atrial fibrillation. It is severe enough that he is forced to wear a heart monitor.

"I want to do something about it and try to get a better quality of life," he said. "When it's out of rhythm you just feel miserable. You're light-headed, you feel dizziness."

In an operating room at Stanford Hospital, Dr. Amin Al-Ahmad is preparing to perform a robotic procedure to correct Dave's heartbeat by ablation; zapping the irregular tissue and destroying it. He says this advanced technology offers several advantages, including limiting the amount of radiation Dave will receive during the surgery.

"Using the combination of both the robotic system, as well as electro anatomoic mapping system... allows us to really reduce the amount of radiation," said Al-Ahmad.

The team uses fluoroscopy to map the left atrium of Dave's heart. The images it takes are then turned into a precise three-dimensional map.

"So almost like a cartoon of the heart," explained Al-Ahmad. "On the computer we can literally tell the robot to go where we need it to go, and simply do the ablation that way without having to image every time we move the catheter."

Al-Ahmad then uses the 3D images to guide the robotic instrument into Dave's heart. Once inside, he will remove small layers of damaged tissue that are causing the irregular heartbeat.

Without the virtual mapping, surgeons typically have to take scans throughout the procedure to guide them. One European study found the robotic system, known as Sensei X, reduced the amount of fluoroscopy images needed by 44 percent and the total amount of radiation absorbed by the patient by 63 percent.

"So we can reduce radiation quite a bit," said Al-Ahmad.

The Sensei X is FDA-approved, but its use in computer-guided catheter procedures like the one performed on Dave is still considered investigational.

The Mountain View-based company hopes to organize a large-scale clinical trial later this year.

Written and produced by Tim Didion.


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