Patients commonly placed off-center during CT imaging—impacting radiation dose, quality
The variables involved in minimizing radiation exposure during CT imaging are many—but simply placing a patient off-center can result in a surface dose increase of 12 to 49 percent and negatively impact image quality.Emory School of Medicine researchers published findings online March 22 in Current Problems in Diagnostic Radiology.
In a two-part study, authors retrospectively analyzed chest, abdomen and/or pelvis CT scans. They analyzed 57,621 CT scans, determining that the large majority (83.7 percent) were performed with the patient off-centered.
The second part of the study utilized CT imaging on a water phantom and an anthropomorphic phantom, finding the patient centroid is not the same as the geometric center of the patient.
“As each phantom was positioned closer to the x-ray source for the anterior-posterior topogram, the phantoms appeared magnified, and measures of dose…increased,” wrote Courtney C. Moreno, MD with the department of radiology and imaging sciences at Emory University in Atlanta, and colleagues.
“In summary, in the largest series published to date, we have documented the tendency of CT technologists to center patients′ centroids below the isocenter in the CT gantry when centering is performed based on visual estimate,” added Moreno et al.
Matt joined Chicago’s TriMed team in 2018 covering all areas of health imaging after two years reporting on the hospital field. He holds a bachelor’s in English from UIC, and enjoys a good cup of coffee and an interesting documentary.