X-ray computed tomography – or CT – scanners are designed with people of an average build in mind. When obese patients require a CT scan, the additional layers of body fat will produce blurry images if the scanner’s regular settings are used. Clinicians typically address this problem by turning up the power of the scanner. Unfortunately, doing so results in overweight patients receiving higher-than-normal doses of radiation. A new computer modeling system developed at New York’s Rensselaer Polytechnic Institute, however, could help bring those levels down.

According to research conducted at Rensselaer, obese mens’ internal organs receive an average of 62 percent more radiation than those of average-weight men, during a typical CT scan. For women, the figure is 59 percent. In either case, although the increased exposure might not amount to much for just one session, it could definitely add up over the course of multiple scans.

Professor of nuclear engineering Xie George Xu is hoping to minimize that extra radiation, with his soon-to-be-released VirtualDose software package. In the creation of the software, Xu led a team that developed “ultra-realistic” 3D computer models of bodies exhibiting various levels of obesity – those models are known as “phantoms.” The researchers also used computer simulations, to determine how X-rays interacted with the body tissues of each of those models.

To use the software, physicians would start by inputting data regarding the patient, such as their age, sex, height and weight – for a female patient, it could also be indicated whether or not she were pregnant. Using this information, VirtualDose would determine which of the phantoms matched the physique of the individual patient. It would then display how much radiation would result from using different scanning configurations to image their organs, leaving it up to the physician to choose one that involved the least amount of radiation, while still providing decent images.

The software would also keep track of the cumulative amount of radiation received by the patient during scans, throughout their lifetime.

A paper on the research was published today, in the journal Physics in Medicine & Biology.