Merging Multiple CT Scans Simplifies Probe Repositioning during Radiofrequency Ablation

Compiling multiple computed tomography (CT) images (summation of CT scans) increases the accuracy of probe repositioning during radiofrequency ablation treatments of various lesions, according to a recent study.

"During radiofrequency ablation, the probe often needs to be repositioned in order to effectively treat an entire lesion,” said John M. Gemery, M.D., from Dartmouth-Hitchcock Medical Center (Lebanon, NH, USA) and author of the study. "During radiofrequency ablation it is hard to determine the areas that have already been treated when moving the probe around. Looking at summated images of several CT scans allows one to quickly check where the ablation probe has been,” he said.

There have been 40 patients successfully treated using the summation method. According to Dr. Gemery, probe repositioning has most typically been used on patients who have lesions within the liver and kidneys; however, it also has been used on lesions found in the lungs and bones.

"The summation method allows for three or more probe placements to be seen at one time. It is very easy to use and it is helpful,” said Dr. Gemery. "It gives you a rapid and accurate picture of where the lesion has been treated. On a single slice scanner, it takes about 30 seconds to summate CT scans of different probe placements into a single set of images. On modern scanners with more powerful computers, summation is even quicker. I think that our discovery is an incremental step forward to improving image-guided treatments.”

The study was published in the September 2008 issue of the American Journal of Roentgenology (AJR).

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Dartmouth-Hitchcock Medical Center