Ultra-Low Radiation Dose Body CT Imaging

描述（申请人提供）：计算机断层扫描（CT）对现代医学的重要贡献是显而易见的。近年来，与人体CT相关的辐射剂量问题受到了广泛的关注，部分原因是它的成功和临床使用率很高。由于目前CT辐射暴露水平不存在非零风险的确凿证据，因此迫切需要制定更有力的人体CT剂量降低策略。然而，这必须在不显著损害诊断准确性的情况下实施。该提案的总体目标是开发、优化和评估一种迭代图像重建算法，该算法有望在不影响诊断准确性的情况下，将辐射剂量从当前水平降低70%-90%。通过采用DR-PICCS重建技术，亚msv腹部CT扫描可以在许多临床应用中保持诊断准确性，例如评估尿石症和结肠直肠息肉。对于其他诊断成像应用，剂量减少70%-90%是可能的，同样可以保留诊断性能。我们的回顾性和前瞻性试点研究的初步结果表明，我们的合作转化研究小组提出的研究是可行的。为实现我们提出的总体目标，我们将开展以下具体工作：(1)优化DR-PICCS在超低剂量腹部CT成像中的应用；(2) DR-PICCS重建算法重建的超低剂量诊断性腹部CT图像的前瞻性验证。这一目标包括证明超低剂量DR- PICCS重建与当前标准护理剂量FBP图像在图像噪声和诊断准确性方面的等效性；超低剂量CT DR-PICCS与其他市售重建技术的性能比较；(3)亚msv CT成像用于虚拟结肠镜（CT colonography）筛查的前瞻性验证。该项目的成功完成将为超低剂量腹部CT成像的临床可行性和实用性提供有价值的信息，包括实用技术的优化（目标1），诊断准确性的验证（目标2）以及在结直肠癌筛查中的应用（目标3）。该项目的成功完成还将为临床评估其他超低剂量CT成像重建方法提供方法学范式和独特的CT数据集。

DESCRIPTION (provided by applicant): The important contribution of computed tomography (CT) to modern medicine is readily apparent. Recently, the issue of the radiation dose related to body CT has received considerable attention, in part because of its success and high rate of clinical utilization. Because the absence of a non-zero risk related to the current levels of radiation exposures from CT cannot be conclusively proven, there is a dire need for more robust dose reduction strategies at body CT. This, however, must be implemented without a significant compromise in diagnostic accuracy. The overarching objective of the proposal is to develop, optimize, and evaluate an iterative image reconstruction algorithm that holds a promise to reduce radiation dose by 70%-90% from current levels, without compromising diagnostic accuracy. By employing the proposed DR-PICCS reconstruction, sub-mSv abdominal CT scanning with preserved diagnostic accuracy may be achievable for a number of clinical applications, such as evaluation for urolithiasis and colorectal polyps. For other diagnostic imaging applications, dose reductions on the order of 70%-90% may be possible, again with preserved diagnostic performance. Preliminary results from our retrospective and prospective pilot studies have demonstrated the feasibility of the proposed study by our collaborative translational research group. The following specific aims will be carried out to accomplish our proposed overall objective: (1) Optimization of the DR-PICCS implementation for ultra-low-dose abdominal CT imaging; (2) Prospective validation of ultra-low- dose diagnostic abdominal CT images reconstructed with DR-PICCS reconstruction algorithm. This aim includes demonstration of equivalence in image noise and diagnostic accuracy between ultra-low-dose DR- PICCS reconstructions and current standard-of-care dose FBP images; and performance comparison of ultra- low-dose CT with DR-PICCS against other commercially-available reconstruction techniques; and (3) Prospective validation of sub-mSv CT imaging for virtual colonoscopy (CT colonography) screening. Successful completion of this project will provide valuable information about the clinical feasibility and utility of ultra-low-dose abdominal CT imaging, including optimization of a practical technique (Aim 1), validation of diagnostic accuracy (Aim 2), and application to colorectal cancer screening (Aim 3). The successful completion of the project will also provide a methodological paradigm and unique CT data sets needed to clinically evaluate other ultra-low-dose CT imaging reconstruction methods.