Wu Tung-Hsin, Lu Kun-Mu, Wu Nien-Yun, Wang Shyh-Jen, Mok Greta S P, Yang Bang-Hung, Yang Ching-Ching
aDepartment of Biomedical Imaging and Radiological Sciences, National Yang Ming University bDepartment of Radiology, Shin Kong Wu Ho-Su Memorial Hospital cDepartment of Nuclear Medicine, Taipei Veterans General Hospital, Taipei dDepartment of Medical Imaging and Radiological Sciences, Tzu-Chi College of Technology, Hualien, Taiwan, ROC eBiomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China.
Nucl Med Commun. 2015 Apr;36(4):376-85. doi: 10.1097/MNM.0000000000000251.
The purpose of this study was to investigate the feasibility of using low-dose computed tomography (CT) in coronary artery calcium scoring and PET attenuation correction for patients in different weight categories undergoing cardiac PET/CT examinations.
Calcium scoring computed tomography (CSCT) scans and PET scans of anthropomorphic cardiac phantoms simulating normal-weight, mildly obese, and severely obese patients were acquired with a hybrid PET/CT scanner. CSCT images were acquired at 120 kVp, with tube current ranging from 10 to 550 mA. PET scans were performed in three-dimensional mode, with acquisition time of 3 min/bed position. The image quality of cardiac PET/CT was evaluated by assessing the signal-to-noise ratio. CT-based coronary artery calcium quantification was performed using the Agatston scoring system.
On the basis of our results, the CSCT protocols using tube currents of 50 and 150 mA should be able to achieve the lowest possible radiation dose while maintaining the desired image quality for normal-weight and mildly obese patients undergoing cardiac PET/CT examinations, respectively. When the proposed low-dose CSCT protocols were performed, radiation dose could be reduced by 83.34 and 50% compared with those from CSCT scans acquired with standard tube current settings for normal-weight and mildly obese patients, respectively. In the scanning of severely obese patients, an increase in tube voltage or current would help improve the reliability of image information provided by cardiac PET/CT.
Our study demonstrated the feasibility of low-dose CT protocols for coronary artery calcium scoring and PET attenuation correction in cardiac PET/CT to examine patients in different weight categories. The calculations performed in this work should be able to provide practical information to achieve necessary diagnostic information while keeping radiation dose as low as reasonably achievable.
本研究的目的是探讨在接受心脏PET/CT检查的不同体重类别的患者中，使用低剂量计算机断层扫描（CT）进行冠状动脉钙化评分和PET衰减校正的可行性。
使用混合型PET/CT扫描仪获取模拟正常体重、轻度肥胖和重度肥胖患者的拟人化心脏模型的钙化评分计算机断层扫描（CSCT）和PET扫描。CSCT图像在120 kVp下采集，管电流范围为10至550 mA。PET扫描以三维模式进行，每个床位采集时间为3分钟。通过评估信噪比来评价心脏PET/CT的图像质量。使用阿加斯顿评分系统进行基于CT的冠状动脉钙化定量分析。
根据我们的结果，分别使用50和150 mA管电流的CSCT方案，应该能够在为接受心脏PET/CT检查的正常体重和轻度肥胖患者维持所需图像质量的同时，实现尽可能低的辐射剂量。当执行建议的低剂量CSCT方案时，与使用标准管电流设置为正常体重和轻度肥胖患者采集的CSCT扫描相比，辐射剂量可分别降低83.34%和50%。在扫描重度肥胖患者时，增加管电压或电流将有助于提高心脏PET/CT提供的图像信息的可靠性。
我们的研究证明了在心脏PET/CT中使用低剂量CT方案进行冠状动脉钙化评分和PET衰减校正以检查不同体重类别的患者的可行性。本研究中进行的计算应该能够提供实用信息，以在保持辐射剂量尽可能低的同时获得必要的诊断信息。
