Rana Vijay K, Rudin Stephen, Bednarek Daniel R
Toshiba Stroke and Vascular Research Center, University at Buffalo (State University of New York), Buffalo, NY USA.
Department of Radiology, University at Buffalo (State University of New York), Buffalo, NY USA ; Department of Physiology and Biophysics, University at Buffalo (State University of New York), Buffalo, NY USA ; Department of Neurosurgery, University at Buffalo (State University of New York), Buffalo, NY USA ; Toshiba Stroke and Vascular Research Center, University at Buffalo (State University of New York), Buffalo, NY USA.
Proc SPIE Int Soc Opt Eng. 2015 Mar 18;9412. doi: 10.1117/12.2081700.
A biplane dose-tracking system (Biplane-DTS) that provides a real-time display of the skin-dose distribution on a 3D-patient graphic during neuro-interventional fluoroscopic procedures was developed. Biplane-DTS calculates patient skin dose using geometry and exposure information for the two gantries of the imaging system acquired from the digital system bus. The dose is calculated for individual points on the patient graphic surface for each exposure pulse and cumulative dose for both x-ray tubes is displayed as color maps on a split screen showing frontal and lateral projections of a 3D-humanoid graphic. Overall peak skin dose (PSD), FOV-PSD and current dose rates for the two gantries are also displayed. Biplane-DTS uses calibration files of mR/mAs for the frontal and lateral tubes measured with and without the table in the beam at the entrance surface of a 20 cm thick PMMA phantom placed 15 cm tube-side of the isocenter. For neuro-imaging, conversion factors are applied as a function of entrance field area to scale the calculated dose to that measured with a Phantom Laboratory head phantom which contains a human skull to account for differences in backscatter between PMMA and the human head. The software incorporates inverse-square correction to each point on the skin and corrects for angulation of the beam through the table. Dose calculated by Biplane DTS and values measured by a 6-cc ionization chamber placed on the head phantom at multiple points agree within a range of -3% to +7% with a standard deviation for all points of less than 3%.
开发了一种双平面剂量跟踪系统（Biplane-DTS），该系统可在神经介入荧光透视过程中，在三维患者图形上实时显示皮肤剂量分布。Biplane-DTS利用从数字系统总线获取的成像系统两个龙门架的几何形状和曝光信息来计算患者皮肤剂量。针对每个曝光脉冲计算患者图形表面上各个点的剂量，并将两个X射线管的累积剂量以彩色图的形式显示在分屏上，该分屏展示了三维人形图形的前后位和侧位投影。还会显示两个龙门架的总体皮肤剂量峰值（PSD）、视野PSD和当前剂量率。Biplane-DTS使用在等中心管侧15 cm处放置的20 cm厚PMMA体模入口表面，在有和没有检查床位于射野内的情况下，测量得到的前后位和侧位管的mR/mAs校准文件。对于神经成像，应用转换因子作为入射野面积的函数，将计算剂量按比例缩放至使用包含人类头骨的幻影实验室头部体模测量的剂量，以考虑PMMA和人类头部之间反向散射的差异。该软件对皮肤上的每个点进行平方反比校正，并校正射束通过检查床的角度。Biplane DTS计算的剂量与放置在头部体模上多个点的6 cc电离室测量值在-3%至+7%的范围内一致，所有点的标准差小于3%
