Simultaneous Comparison of Image Quality and Radiation-Induced Cancer Risk in Brain CT Scans among Different Scanners

The parameters of image quality depend on the radiation dose and the CT scanner type. This study aimed to simultaneously compare the image quality and the risk of carcinogenesis caused by radiation in the CT scan of the brain in different scanners.

The present descriptive-analytical cross-sectional study was conducted on 200 patients who had been referred to hospitals of Isfahan city including Kashani (Siemens (scanner 1) and Canon (scanner 2)), Al-Zahra (General Electric (scanner 3)), Isa bin Maryam (Neusoft (Scanner 4)) for brain CT scan. Organ doses and effective doses of patients were obtained with a calculating program, Impact dose, and risk of exposure-induced death (REID) values estimated by the PCXMC program. The image quality was evaluated by examining the parameters of image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). To compare different scanners, the CNR to REID ratio was introduced as the C criterion.

The average values of REID for scanners 1 to 4 were obtained at 2.98, 4.46, 5.07, and 4.65 per 100,000 men and 3.22, 6.16, 6.53, and 6.26 per 100,000 women, respectively. The average CNR values for scanners 1 to 4 were 1.24, 1.05, 1.66 and 2.08, respectively. Scanners 1 and 2 had the highest and lowest C criteria, respectively.

The results of this study showed that the radiation dose and the risk caused by radiation in the brain CT scan test should always be evaluated considering the image quality parameters, and a scanner with a higher CNR to REID ratio is more suitable.