Chest CT screening in patients with overweight or obesity using spectral shaping at 150 kVp: compared with 120 kVp protocol and spectral shaping at 100 kVp protocol.

PURPOSE

To evaluate the image quality (IQ) and the figure of merit (FoM) of chest CT screening in patients with overweight or obesity using a tin filter for spectral shaping at 150 kVp.

MATERIALS AND METHODS

Patients with overweight or obesity (N = 150, body mass index ≥ 26 kg/m) with indications for chest CT screening were prospectively enrolled and randomly divided into three groups: 120 kVp group (standard radiation dose/tube voltage, 120 kVp/CT volume does index, 4.68 mGy); Sn100 kVp group (1/10th radiation dose level/100 kVp with a tin filter/0.47 mGy); Sn150 kVp group (1/2th radiation dose level/150 kVp with a tin filter/2.34 mGy). IQ and FoMs were evaluated and compared among the three groups.

RESULTS

Image noise, signal-to-noise ratios and subjective IQ scores were significantly higher in the Sn150 kVp group than those in the Sn100 kVp group (all p < 0.05), but were not significantly different with those in the 120 kVp group. FoMs in the Sn150 kVp group were significantly higher than those in the 120 kVp group (all p < 0.05), but showed no statistical difference with those in the Sn100 kVp group.

CONCLUSIONS

Compared with scanning at 120 kVp, chest CT screening performed at 150 kVp with spectral shaping substantially reduces the radiation dose in overweight and obese patients while maintaining IQ.