Combining automatic tube voltage selection (ATVS) with automatic tube current modulation (ATCM) significantly decreases the radiation dose from abdominal and thoracic contrast-enhanced CT scans compared with ATCM alone, according to a study published in the August issue of the American Journal of Roentgenology.

CT radiation dose rates were reduced overall by 18 percent when combining the automatic tools, the study found. Rates were reduced 16.8 percent for CT chest scans and 18.4 percent for abdomen CT scans.

“Our study showed that by using ATVS an overall decrease in radiation dose of 18 percent is feasible,” wrote lead author Caroline Mayer, MD, of University Medical Center Mannheim in Mannheim, Germany, and colleagues. Other studies have come to similar conclusions, they added.

The retroactive study, which examined both radiation dose and image quality, examined 617 patients who all underwent contrast- enhanced chest or abdominal CT and divided them into two groups.

Group A included 317 patients who underwent CT with only ATCM and a fixed body mass index–adjusted tube voltage (120 kV or 100 kV). ATCM and ATVS were both used on the patients in group B.

The study also further analyzed those patients who benefited from ATVS and found that in a subgroup analysis, tube voltage was reduced in 35 percent of the abdomen examinations and 60 percent of the chest examinations.

“Given that tube voltage has an exponential relationship with radiation dose lowering the tube voltage may also be an effective approach to reduce radiation exposure because of the introduction of ATVS,” wrote the authors.