Mei Kai, Pasyar Pouyan, Geagan Michael, Liu Leening P, Shapira Nadav, Gang Grace J, Stayman J Webster, Noël Peter B
University of Pennsylvania.
Johns Hopkins University.
Res Sq. 2023 Apr 26:rs.3.rs-2828218. doi: 10.21203/rs.3.rs-2828218/v1.
The objective of this study is to create patient-specific phantoms for computed tomography (CT) that have realistic image texture and densities, which are critical in evaluating CT performance in clinical settings. The study builds upon a previously presented 3D printing method (PixelPrint) by incorporating soft tissue and bone structures. We converted patient DICOM images directly into 3D printer instructions using PixelPrint and utilized stone-based filament to increase Hounsfield unit (HU) range. Density was modeled by controlling printing speed according to volumetric filament ratio to emulate attenuation profiles. We designed micro-CT phantoms to demonstrate the reproducibility and to determine mapping between filament ratios and HU values on clinical CT systems. Patient phantoms based on clinical cervical spine and knee examinations were manufactured and scanned with a clinical spectral CT scanner. The CT images of the patient-based phantom closely resembled original CT images in texture and contrast. Measured differences between patient and phantom were less than 15 HU for soft tissue and bone marrow. The stone-based filament accurately represented bony tissue structures across different X-ray energies, as measured by spectral CT. In conclusion, this study demonstrated the possibility of extending 3D-printed patient-based phantoms to soft tissue and bone structures while maintaining accurate organ geometry, image texture, and attenuation profiles.
本研究的目的是创建用于计算机断层扫描（CT）的患者特异性体模，这些体模具有逼真的图像纹理和密度，这对于在临床环境中评估CT性能至关重要。该研究基于先前提出的一种3D打印方法（PixelPrint），通过纳入软组织和骨骼结构进行构建。我们使用PixelPrint将患者的DICOM图像直接转换为3D打印机指令，并利用基于石膏的细丝来增加亨氏单位（HU）范围。通过根据体积细丝比例控制打印速度来模拟衰减曲线，从而对密度进行建模。我们设计了微型CT体模以证明其可重复性，并确定细丝比例与临床CT系统上HU值之间的映射关系。基于临床颈椎和膝关节检查的患者体模被制造出来，并使用临床光谱CT扫描仪进行扫描。基于患者的体模的CT图像在纹理和对比度方面与原始CT图像非常相似。对于软组织和骨髓，患者与体模之间的测量差异小于15 HU。通过光谱CT测量，基于石膏的细丝在不同X射线能量下准确地呈现了骨组织结构。总之，本研究证明了将3D打印的基于患者的体模扩展到软组织和骨骼结构的可能性，同时保持准确的器官几何形状、图像纹理和衰减曲线。
