Merging multiple CT images increases the accuracy of probe repositioning during radiofrequency ablation treatments of various lesions, according to a recent study published in the September issue of the American Journal of Roentgenology.

"During radiofrequency ablation the probe often needs to be repositioned in order to effectively treat an entire lesion," said John M. Gemery, MD, author of the study conducted at Dartmouth-Hitchcock Medical Center in Lebanon, N.H.

"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.

According to Gemery, probe repositioning has most commonly 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, giving a rapid and accurate picture of where the lesion has been treated, Gemery said. On a single slice scanner, it takes about 30 seconds to summate CT scans of different probe placements into a single set of images.

"I think that our discovery is an incremental step forward to improving image-guided treatments,” Gemery said.