Xiong Zhenyu, Vijayan Sarath, Rudin Stephen, Bednarek Daniel R
University at Buffalo, Department of Physiology and Biophysics, 124 Sherman Hall, 3435 Main Street, Buffalo, New York 14214, United States.
Toshiba Stroke & Vascular Research Center, 875 Ellicott Street, Buffalo, New York 14203, United States.
Proc SPIE Int Soc Opt Eng. 2017 Feb 11;10132. doi: 10.1117/12.2254061. Epub 2017 Mar 9.
In some medical-imaging procedures using CBCT and fluoroscopy, it may be needed to visualize only the center of the field-of-view with optimal quality. To reduce the dose to the patient as well as enable increased contrast in the region of interest (ROI) during CBCT and fluoroscopy procedures, a 0.7 mm thick Cu ROI attenuator with a circular aperture 12% of the FOV was used. The aim of this study was to quantify the dose-reduction benefit of ROI imaging during a typical CBCT and interventional fluoroscopy procedures in the head and torso. The Toshiba Infinix C-Arm System was modeled in BEAMnrc/EGSnrc with and without the ROI attenuator. Patient organ and effective doses were calculated in DOSXYZnrc/EGSnrc Monte-Carlo software for CBCT and interventional procedures. We first compared the entrance dose with and without the ROI attenuator on a 20 cm thick solid-water block. Then we simulated a CBCT scan and an interventional fluoroscopy procedure on the head and torso with and without an ROI attenuator. The results showed that the entrance-surface dose reduction in the solid water is about 85.7% outside the ROI opening and 10.5% in the ROI opening. The results showed a reduction in most organ doses of 45%-70% and in effective dose of 46%-66% compared to the dose in a CBCT scan and in an interventional procedure without the ROI attenuator. This work provides evidence of substantial reduction of organ and effective doses when using an ROI attenuator during CBCT and fluoroscopic procedures.
在一些使用锥形束CT（CBCT）和荧光透视的医学成像程序中，可能只需要以最佳质量可视化视野中心。为了在CBCT和荧光透视程序中减少患者的辐射剂量并提高感兴趣区域（ROI）的对比度，使用了一个0.7毫米厚的铜制ROI衰减器，其圆形孔径为视野的12%。本研究的目的是量化在头部和躯干的典型CBCT和介入性荧光透视程序中ROI成像的剂量减少益处。东芝Infinix C型臂系统在BEAMnrc/EGSnrc中进行了有和没有ROI衰减器的建模。在DOSXYZnrc/EGSnrc蒙特卡罗软件中计算了CBCT和介入程序的患者器官剂量和有效剂量。我们首先比较了在一个20厘米厚的固体水模体上有和没有ROI衰减器时的入射剂量。然后我们模拟了有和没有ROI衰减器时头部和躯干的CBCT扫描和介入性荧光透视程序。结果表明，在固体水中，ROI开口外的入射表面剂量减少约85.7%，ROI开口内减少10.5%。结果显示，与没有ROI衰减器的CBCT扫描和介入程序相比，大多数器官剂量减少了45%-70%，有效剂量减少了46%-66%。这项工作提供了证据，证明在CBCT和荧光透视程序中使用ROI衰减器时，器官剂量和有效剂量会大幅减少。
