"The objective of tin filtration is to suppress low-energy photons of the polychromatic x-ray beam; these photons are absorbed by the patient while not useful for the creation of CT images," Dr. Martine Rémy-Jardin, PhD, chief of thoracic imaging at Calmette Hospital in Lille, France, told AuntMinnie.com.
The group examined 50 patients with a body mass index of at least 25 kg/m2 for follow-up of a chronic respiratory disease. Each patient had two exams: The first was obtained with a second-generation dual-source CT scanner with individually adapted kV selection based on the patient's body weight. The second scan was performed with a third-generation dual-source CT scanner at 150 kV with tin filtration to maintain constant radiation exposure. Iterative reconstruction was used on both groups.
Results for the patients scanned with the tin filter showed a "significant reduction in the image noise and a significantly improved [contrast-to-noise ratio] compared to acquisitions at 140 kVp/90 mAs in the same population," Rémy-Jardin said. The protocol improved overall image quality without increasing the radiation exposure.
