To explore the application value and significance of anteroposterior and lateral localizer radiographs in reducing the radiation dose in adult chest CT with CARE Dose 4D technique.

Totally 120 patients undergoing chest CT scan were randomly divided into 2 groups (test group and control group, with 60 cases in each group) according to random nuber table. Anteroposterior and lateral localizer radiographs were performed for experimental group and anteroposterior localizer radiograph for control group, both being scanned with CARE Dose 4D technique. CTDI_vol, DLP, image noise and subjective image quality in two groups were recorded and compared.

Averages of CTDI_vol and DLP were (5.11±0.87) and (159.58±30.65) mGy·cm in test group, and (6.56±1.74) and(211.5±65.89)mGy·cm in control group, respectively. Compared with control group, average CTDI_vol decreased by 1.45 mGy (22.1%) and average DLP decreased by 51.92 mGy (24.5%) in test group, with statistically significant differences (t=-5.75, -5.88, P<0.05). Image noise levels were 12.6±1.8 in sternoclavicular joint, 10.9±1.4 in tracheal bifurcation and 11.1±1.8 in left ventricular in test group, and 11.5±1.7 in sternoclavicular joint, 10.5±1.6 in tracheal bifurcation, 10.9±1.9 in left ventricular in control group, respectively. Noise values at acromioclavicular joint level between two groups were statistically significant (t=5.03, P<0.05), but not in bifurcation of trachea and left ventricular (P>0.05). Subjective image quality scores in two groups were consistent with the requirements of clinical diagnosis(χ²=1.37, P>0.05).

Adult chest CT scan with anteroposterior and lateral localizer radiographs using CARE Dose 4D technology can guarantee image quality while further reducing the radiation dose to patients.

Tomography; X-ray computed; Chest; CARE Dose 4D; Radiation dose; Image quality