Background/Objectives: The primary aim of this study was to evaluate whether the replacement of roughly one-decade-old computed tomography (CT) scanners with new-model CT scanners were associated with an additional reduction in the radiation dose delivered to oncological patients, in a radiological setting where the optimization of protocols had already reached very low radiation doses. An exploratory secondary objective was to evaluate the potential differences in the objective image quality between the CT scans obtained before and after the installation of the new-generation CT scanners. Methods: Chest and abdominal CT examinations conducted for oncologic purposes were retrospectively selected from two time periods—prior to scanner replacement (2022) and following an upgrade (2024)—after five CT systems in our radiology department were replaced. We extracted and compared the CT dose index (CTDI) and dose length product (DLP) for each CT phase. For the objective image quality evaluation, we calculated the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) at the center of the liver and the aorta. An appropriate statistical analysis was performed and ap-value < 0.05 was considered significant. Results: We included 14,601 CT acquisitions, of which 9013 (61.7%) were performed before and 5588 (38.3%) after the replacement of the CT scanners. There were significantly lower values for the CTDI and DLP with the new CT scanners compared to the old ones. The CTDI with the new CT scanners was significantly lower in all phases (p-value = 0.002 for unenhanced phase, andp< 0.001 for arterial, portal venous, and delayed phases). The DLP using the new CT scanners was significantly lower in the arterial, portal venous, and delayed phases (p< 0.001), and it was not significantly different in the unenhanced phase (p= 0.36). There was no significant difference in the SNR at the liver level (p= 0.72) or at the aorta level (p= 0.51). There was no significant difference in the CNR at the liver level (p= 0.24), whereas the CNR was higher with the new CT scanners at the aorta level (p= 0.03). Conclusions: The transition to new-model CT scanners resulted in a significant reduction in the radiation dose delivered by chest and abdomen CT scans, without compromising the objective image quality.
背景/目的：本研究的主要目的是评估，在放射学实践中，当扫描方案优化已达到极低辐射剂量水平时，将使用约十年的旧计算机断层扫描（CT）设备更换为新型号CT设备，是否与肿瘤患者所受辐射剂量的进一步降低相关。探索性的次要目的是评估新一代CT设备安装前后所获CT扫描图像在客观图像质量方面的潜在差异。方法：在我们放射科的五台CT系统完成更换后，回顾性选取了两个时间段（设备更换前的2022年与设备升级后的2024年）为肿瘤学目的进行的胸部及腹部CT检查。我们提取并比较了每个CT扫描期的CT剂量指数（CTDI）和剂量长度乘积（DLP）。对于客观图像质量评估，我们计算了肝脏中心和主动脉中心的信噪比（SNR）与对比噪声比（CNR）。进行了适当的统计分析，p值<0.05被认为具有统计学意义。结果：我们共纳入14,601次CT采集，其中9013次（61.7%）在CT设备更换前进行，5588次（38.3%）在更换后进行。与旧设备相比，新CT设备的CTDI和DLP值均显著降低。在所有扫描期，新CT设备的CTDI均显著更低（平扫期p值=0.002，动脉期、门静脉期及延迟期p<0.001）。新CT设备的DLP在动脉期、门静脉期及延迟期显著更低（p<0.001），在平扫期无显著差异（p=0.36）。在肝脏水平（p=0.72）和主动脉水平（p=0.51）的SNR均无显著差异。在肝脏水平的CNR无显著差异（p=0.24），而在主动脉水平，新CT设备的CNR更高（p=0.03）。结论：更换为新型号CT设备显著降低了胸部及腹部CT扫描的辐射剂量，且未损害客观图像质量。
Radiation Dose Reduction in Cancer Imaging with New-Model CT Scanners: A Quality of Care Evaluation
肿瘤(癌症)患者之家