Low tube voltage dual source computed tomography to reduce contrast media doses in adult abdomen examinations: A phantom study.
OBJECTIVE
To evaluate the potential of low tube voltage dual source (DS) single energy (SE) and dual energy (DE) computed tomography (CT) to reduce contrast media (CM) dose in adult abdominal examinations of various sizes while maintaining soft tissue and iodine contrast-to-noise ratio (CNR).


METHODS
Four abdominal phantoms simulating a body mass index of 16 to 35 kg/m(2) with four inserted syringes of 0, 2, 4, and 8 mgI/ml CM were scanned using a 64-slice DS-CT scanner. Six imaging protocols were used; one single source (SS) reference protocol (120 kV, 180 reference mAs), four low kV SE protocols (70 and 80 kV using both SS and DS), and one DE protocol at 80/140 kV. Potential CM reduction with unchanged CNRs relative to the 120 kV protocol was calculated along with the corresponding increase in radiation dose.


RESULTS
The potential contrast media reductions were determined to be approximately 53% for DS 70 kV, 51% for SS 70 kV, 44% for DS 80 kV, 40% for SS 80 kV, and 20% for DE (all differences were significant, P < 0.05). Constant CNR could be achieved by using DS 70 kV for small to medium phantom sizes (16-26 kg/m(2)) and for all sizes (16-35 kg/m(2)) when using DS 80 kV and DE. Corresponding radiation doses increased by 60%-107%, 23%-83%, and 6%-12%, respectively.


CONCLUSIONS
DS single energy CT can be used to reduce CM dose by 44%-53% with maintained CNR in adult abdominal examinations at the cost of an increased radiation dose. DS dual-energy CT allows reduction of CM dose by 20% at similar radiation dose as compared to a standard 120 kV single source.
Department of Diagnostic Medical Physics, Karolinska University Hospital, Stockholm 14186, Sweden.
Daniel
D
Thor
Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Karolinska University Hospital in Huddinge, Stockholm 14186, Sweden.
Torkel B
TB
Brismar
Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Karolinska University Hospital in Huddinge, Stockholm 14186, Sweden.
Michael A
MA
Fischer
D000005:Abdomen / Q000528:radiation effects; D000328:Adult; D049628:Body Size; D003287:Contrast Media / Q000009:adverse effects*; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000009:adverse effects / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000295:instrumentation*
D003287:Contrast Media