Patrik Rogalla MD, Presenter: Nothing to Disclose

Christian Kloeters MD, Abstract Co-Author: Nothing to Disclose

Patrick Alexander Hein MD, Abstract Co-Author: Nothing to Disclose

Bernd K. Hamm MD, Abstract Co-Author: Research Consultant, Bayer AG Research Consultant, Toshiba Corporation Stockholder, Siemens AG Stockholder, General Electric Company Stockholder, Biomed Research grant, Toshiba Corporation Research grant, Koninklijke Philips Electronics NV Research grant, Siemens AG Research grant, General Electric Company Research grant, Elbit Medical Imaging Ltd Research grant, Bayer AG Research grant, Guerbet AG Research grant, Bracco Group Research grant, B. Braun Research grant, Knauth Research grant, Boston Group Equipment support, Elbit Medical Imaging Ltd Investigator, Copenhagen Malmo Contrast AB, Lund, Sweden

Alexander Ewald Lembcke MD, Abstract Co-Author: Nothing to Disclose

Brigitte Stoever MD, Abstract Co-Author: Nothing to Disclose

To determine the radiation dose and to evaluate the image quality of 320-slice dynamic volume CT in children.

39 patients (1 day–14 years, mean: 2.1 years, median: 0.8 years) underwent a dynamic volume CT (Toshiba Aquilion One). The scan parameters wer as follows: 80 kV for scans follwing intravenous contrast material injection, 120 kV in non-contrast scans, 10-50 mA, 0.35 to 0.5s gantry rotation time, 1-3 rotation acquisition. The formula (body weight in [kg]+5) x f was used for mAs calculation with f=1 for chest and 1.5 for abdominal scans at 120 kV. For 80 kV scans, the mAs-value was multiplied by a factor of 2.5. In non-cooperative patients and patients not able to hold their breath, 3 rotations at 0.35 s were acquired to shift the reconstruction within the acquisition window for motion artifact reduction. All scans were evaluated in respect to image quality on a scale of 1-3 (1= poor, 3=good), the resulting radiation dose was calculated based on the DLP displayed on the patient dose report and veryfied using commercially available software for dose calculation in CT (CT-Expo).

16 cm detector coverage sufficed for scanning of the target area with exception of four patients (two chest, two abdominal scans). None of the scans was rated poor, one patient moved despite manual fixation so that a repeat scan was deemed necessary. Despite continuous respiratory motion in 10 patients, axial slices were rated as good, in one patient, motion blur was rated relevant but did not hinder diagnosis. Radiation exposure (calculated by both methods) ranged from 0.2 to 2.3 mSv, depending on the scanning area and parameters used.

Although no intraindividual comparison to helical CT was performed, 320-slice dynamic volume CT carries the potential for dose reduction in the pediatric patient population without the penalty of poor image quality. Motion artifacts rarely occur.

320-slice non-helical CT represents a further advancement to reduce radiation dose in pediatric CT scanning.

Rogalla, P, Kloeters, C, Hein, P, Hamm, B, Lembcke, A, Stoever, B, Radiation Dose and Imaging Protocols in Pediatric Dynamic Volume CT.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8016793.html