Application of Care kV combined with Care Dose 4D in abdominal CT

Objective To study the application of the intelligent optimum tube voltage (Care kV) combined with automatic tube current (Care Dose 4D) technique in dual source CT scanning for the abdomen. Methods 180 adult patients underwent whole abdominal CT examination from February 2016 to March 2016 of were selected as the retrospective research objects. On the basis of reference mAs of the image quality the patients were divided into three groups using completely randomized grouping method with 60 patients in each group, such as 250 mAs group, 200 mAs group, and 150 mAs group. The other scanning parameters and image reconstruction parameters were the same. The liver parenchyma CT values and image noise(SD) at the second hepatic portal level were measured. The signal-to-noise ratios (SNR) in the three groups were compared as well as contrast to noise ratio (CNR), noise (SD), the average volume CT dose index (CTDIvol), dose length product (DLP) and effective dose(E). Results The kV and mAs values in the plain scan, arterial phase scan and portal phase scan in the three groups of patients had statistically significant differences(F=35.25, P 0.05). In 250 mAs group and 150 mAs group, the SNR and the noise of plain scan and arterial phase images had no statistically significant difference (F=1.98, P>0.05), and SNR of portal phase images and CNR of three phases had statistically significant difference (F=27.64, P 0.05), and the SNR and CNR of portal phase images had significant difference (F=19.63, P< 0.05). Conclusions For the combined use of Care kV and Care dose 4D, it is feasible to select appropriate reference mAs in reducing radiation dose without sacrificing imaging quality. Key words: Tomography, X-ray computed; Intelligent optimum tube voltage technique(Care kV); Radiation dose