Recently, dose-reduction techniques have been the focus of radiation-based medical applications. In the present study, a region of interest (ROI) based imaging technique for dose reduction and attempted to solve the limitations and problems of conventional ROI imaging techniques by suggesting a novel hybrid scanning technique were developed. A prototype of the computed tomography (CT) system (TVX-IL1500H, GERI, Korea) and an RSD anthropomorphic head phantom were used to obtain the reconstructed image using two types of hybrid scanning techniques with source-to-detector distance and source-to-center rotation distance of 1178 mm and 905 mm, respectively. Hybrid CT images were reconstructed with a combination of truncated and nontruncated projections using the filtered back projection (FBP) reconstruction algorithm. The proposed hybrid CT scan was divided into alternating scans and half-scans. Optimization of hybrid CT scanning was performed using an acquisition parameter called the hybrid scanning weighting factor (HSWF), and image quality was evaluated by acquiring images according to each HSWF value. An image restoration method, based on the projection onto convex sets (POCS) algorithm introduced in our previous study, was used to correct the truncated projection data. The reconstructed image quality was analyzed using the structural similarity index (SSIM), contrast-to-noise ratio (CNR), and figure-of-merit (FOM). Consequently, appropriate acquisition parameter values for alternating half-scans in the hybrid scan were obtained and verified.

中文翻译：

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混合扫描技术参数对剂量减少和 CT 图像质量的可行性研究


最近，剂量减少技术已成为基于辐射的医疗应用的重点。在本研究中，一种基于感兴趣区域 （ROI） 的成像技术用于减少剂量，并试图通过提出一种新的混合扫描技术来解决传统 ROI 成像技术的局限性和问题。使用两种类型的混合扫描技术（源到探测器的距离和源到中心的旋转距离分别为 1178 mm 和 905 mm），使用计算机断层扫描 （CT） 系统的原型 （TVX-IL1500H，GERI，韩国） 和 RSD 拟人化头部模型来获得重建图像。使用过滤后的反向投影 （FBP） 重建算法，通过截断和非截断投影的组合重建混合 CT 图像。提出的混合 CT 扫描分为交替扫描和半扫描。使用称为混合扫描加权因子 （HSWF） 的采集参数进行混合 CT 扫描的优化，并根据每个 HSWF 值采集图像来评估图像质量。基于我们之前研究中介绍的投影到凸集 （POCS） 算法的图像恢复方法用于校正截断的投影数据。使用结构相似性指数 （SSIM） 、对比度噪声比 （CNR） 和品质因数 （FOM） 分析重建的图像质量。因此，获得并验证了混合扫描中交替半扫描的适当采集参数值。