Compiling multiple CT scans simplifies repositioning during radiofrequency ablation

Merging multiple CT images (summation of CT scans) increases the accuracy of probe repositioning during radiofrequency ablation treatments of various lesions, according to a recent study performed at Dartmouth-Hitchcock Medical Center in Lebanon, NH.

"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. "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 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. "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," he said.

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

This study appears in the September issue of the American Journal of Roentgenology.

For a copy of the full study, please contact Heather Curry via email at hcurry@arrs.org.

The American Roentgen Ray Society (ARRS) was founded in 1900 and is the oldest radiology society in the United States. Its monthly journal, the American Journal of Roentgenology, began publication in 1906. Radiologists from all over the world attend the ARRS annual meeting to participate in instructional courses, scientific paper presentations and scientific and commercial exhibits related to the field of radiology. The Society is named after the first Nobel Laureate in Physics, Wilhelm Röentgen, who discovered the x-ray in 1895.