SU-E-I-80: Optimizing Scanning-Beam Digital X-Ray Tomosynthesis of the Lungs.
SU-E-I-80: Optimizing Scanning-Beam Digital X-Ray Tomosynthesis of the Lungs.
复制标题
SU-E-I-80：优化肺部扫描束数字 X 射线断层合成。
DOI：
10.1118/1.4734797
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发表时间：
2012
期刊：
影响因子：
3.8
通讯作者：
Fahrig,R
中科院分区：
文献类型：
--
作者：
Nelson,G;Yoon,S;Krishna,G;Wilfley,B;Fahrig,R
目的：我们提出优化用于肺肿瘤活检的扫描束数字断层扫描系统（SBDX）的几何结构，从而为目标验证提供实时三维断层扫描重建。该系统的独特几何形状需要在患者剂量、成像视野和断层合成角度之间进行权衡。方法采用蒙特卡罗模拟软件PCXMC，对源到探测器距离（SDDs）在90cm ~ 150cm范围内的目标器官剂量、平均体剂量和有效剂量（ICRP 60和ICRP 103）进行计算。为了方便对我们的系统进行建模，我们创建了一个修改版本的PCXMC。我们还使用matlab来评估相同的sdd在整个视场中产生的可能的断层合成角度。结果为使断层合成角度最大化，同时为患者留出空间，SDD在90cm ~ 110cm之间为宜。在SDD 100cm处，患者中心距离检测器40 cm处，在荧光模式下操作，SBDX系统提供的剂量是正常移动透视系统以30 fps工作的0.38倍。由于系统的逆几何结构，当病人靠近检测器时，给病人的剂量就会增加。在5厘米的视场范围内，可以实现高达15度的断层合成角度。为了减少SDD和增加断层合成角度，患者必须被放置在距离探测器45cm的范围内。结论我们优化的几何形状的剂量率是可以接受的，尽管可能需要更高的剂量率来改善结节的可见性。额外的剂量优化步骤包括修改扫描光束模式以优化断层合成图像获取。活检过程中的总剂量可能会减少，因为结节靶向性将得到改善，所需活检的总次数将减少。这项工作已获得NIH拨款R21 HL098683以及卢卡斯基金会的资助。
PurposeWe propose to optimize the geometry of the Scanning‐Beam Digital Tomography system (SBDX) for application to lung tumor biopsies, thereby providing real‐time 3D tomographic reconstructions for target verification. The unique geometry of the system requires trade‐offs between patient dose, imaging field of view and tomosynthesis angle.MethodsWe used PCXMC, a Monte Carlo simulation software package, to determine the dose to organs of interest as well as the Average body dose and Effective Dose (both ICRP 60 and 103) for source to detector distances (SDDs) between 90cm and 150cm. To facilitate modeling our system, a modified version of PCXMC was created. We also used matlab to evaluate the possible tomosynthetic angles thatResultacross the field of view for the same SDDs.ResultsTo maximize the tomosynthesis angle while leaving space for the patient, an SDD of between 90cm and 110cm is appropriate. At SDD 100cm, patient centered at 40 cm from the detector, operated in fluoro mode, the SBDX system delivers ∼0.38x the dose of a normal mobile fluoroscopy system operating at 30 fps. Because of the inverse geometry of the system, the dose to the patient goes up as the patient gets closer to the detector. Tomosynthetic angles up to 15 degrees over a 5‐cm field‐of‐view can be achieved for this geometry. The patient must be placed within 45cm of the detector in order to achieve the benefits from reduced SDD and increased tomosynthetic angle.ConclusionsThe dose‐rate for our optimized geometry is acceptable, although higher dose rates for improved nodule visualization may be required. Additional dose optimization steps include modifying the scanning beam pattern to optimize for tomosynthetic image acquisition. Overall dose during the biopsy procedure will likely decrease since nodule targeting will be improved and the overall number of biopsies required will be reduced. This work has received funding from NIH grant R21 HL098683, as well as from the Lucas Foundation.