Parameter optimization for ultra-low dose computed tomography of the chest using spectral purification technology
10.3760/cma.j.cn112271-20240530-00204
- VernacularTitle:能谱纯化技术优化胸部超低剂量CT参数的研究
- Author:
Chengxin KANG
1
;
Wangjia LI
1
;
Binjie FU
1
;
Zhigang CHU
1
;
Fajin LYU
1
Author Information
1. 重庆医科大学附属第一医院放射科，重庆 40016
- Publication Type:Journal Article
- Keywords:
Ultra-low dose computed tomography;
Pulmonary nodule;
Radiation dose;
Phantom
- From:
Chinese Journal of Radiological Medicine and Protection
2025;45(4):356-361
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To optimize the scan parameters for ultra-low dose computed tomography (ULDCT) of the chest using spectral purification technology, and assess the feasibility of maintaining image quality while reducing radiation dosage.Methods:An anthropomorphic chest phantom embedded with simulated pulmonary nodules was utilized for low-dose computed tomography(LDCT) and ULDCT scans. LDCT was conducted using a reference tube current of 25 mAs and a pitch of 1.0. ULDCT incorporating spectral purification technology was conducted using four reference tube currents, i. e., 50, 100, 150, and 200 mAs (labeled ULDCT1-4), and a pitch of 1.5. Other parameters were consistent. The volume CT dose index and the dose-length product were extracted from the dose reports, and then the effective doses were calculated. The objective image quality was assessed using metrics including image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). The subjective image quality of ULDCT images was assessed on a four-point scale with LDCT images as reference.Results:The ULDCT4 at a reference tube current of 200 mAs showed a lower effective dose compared to LDCT ( t = -17.30, P < 0.001). The objective image quality assessments indicated that noise levels in four ULDCT groups were higher than those in LDCT ( t = 21.96, 10.56, 3.15, 3.14, P < 0.05). Notably, the SNR and CNR for the aortic arch were higher in ULDCT4 compared to LDCT ( t = 3.55, 71.96, P < 0.05). The SNR of pulmonary nodules in ULDCT4 was comparable to that in LDCT ( P > 0.05), but the CNR was higher ( t = 0.79, P < 0.001). Subjective image quality assessments reveal that the image quality of ULDCT4 was higher than that of LDCT, with scores of 3.80±0.46 for noise, 3.70±0.46 for contrast and sharpness, and 3.37±0.66 for pulmonary nodules. Conclusions:ULDCT (200 mAs) using spectral purification technology can yield higher image quality than LDCT while substantially reducing the radiation dose, thus demonstrating substantial clinical potential and the promise of replacing LDCT in early lung cancer screening.
