Optimal tube current for lung cancer screening with low-dose spiral CT

Purpose: To determine the optimal tube current for spiral CT for lung cance r screening. Material and Methods: Low-dose spiral CT images from 20 subjects were obtai ned with 50 mA, 25 mA, 10 mA and 5 mA tube currents. The accuracy in detect ing 21 nodules measuring 3 to 14 mm in diameter was tested using receiver o perating characteristics (ROC) to determine the diagnostic accuracy and sta tistical significance. Results: Compared with 50 mA, 25 mA showed no statistical difference. A sig nificant difference was seen between 50 mA and 5 mA images and between 25 m A and 10 mA images, in the detection of lung parenchymal nodular lesions. Conclusion: Approximately 25 mA is the optimal tube current for the detecti on of pulmonary nodules as it allows a reduction of the radiation dose with out sacrificing diagnostic accuracy.