Department of Applied Physical Sciences, University of North Carolina at Chapel Hill; Chapel Hill, NC 27599, United States of America.
Department of Physics and Astronomy, University of North Carolina at Chapel Hill; Chapel Hill, NC 27599, United States of America.
Phys Med Biol. 2023 Aug 14;68(17). doi: 10.1088/1361-6560/acea17.
. The aim of this study was to investigate the feasibility of improving the image quality and accuracy of cone beam computed tomography (CBCT) by replacing the conventional wide cone angle x-ray tube with a distributed x-ray source array positioned in the axial direction.. The multisource CBCT (ms-CBCT) design was experimentally simulated using a benchtop scanner with a carbon nanotube x-ray tube and a flat-panel detector. The source was collimated and translated in the axial direction to simulate a source array with a reduced cone angle for each beam. An adjacent scatter ratio subtraction (ASRS) method was implemented for residual scatter reduction. Several phantoms were imaged using the ms-CBCT and conventional CBCT configurations under otherwise similar conditions. The Requirements of the ms-CBCT design on the x-ray source and detector were evaluated.. Compared to the conventional CBCT, the ms-CBCT design with 8 sources and ASRS significantly improved the image quality and accuracy, including: (1) reducing the cupping artifact from 15% to 3.5%; (2) reducing the spatial nonuniformity of the CT Hounsfield unit values from 38.0 to 9.2; (3) improving the contrast-to-noise ratio of the low contrast objects (acrylic and low density polyethylene inserts) against the water-equivalent background by ∼20% and (4) reducing the root-mean-square error of the HU values by 70%, from 420.1 to 124.4. The imaging dose and scanning time used by the current clinical CBCT for maxillofacial imaging can be achieved by current source and detector technologies.. The ms-CBCT design significantly reduces the scatter and improves the image quality and accuracy compared to the conventional CBCT.
本研究旨在探讨通过用轴向排列的分布式射线源阵列替代传统宽角锥形束 CT（CBCT）的射线管来提高 CBCT 图像质量和精度的可行性。使用带有碳纳米管射线管和平板探测器的台式扫描仪对多源 CBCT（ms-CBCT）设计进行了实验模拟。射线源被准直并在轴向方向上平移，以模拟具有减小的每个射束的锥形角的源阵列。实施了相邻散射比减法（ASRS）方法以减少残余散射。在其他条件相似的情况下，使用 ms-CBCT 和传统 CBCT 配置对几个体模进行了成像。评估了 ms-CBCT 设计对射线源和探测器的要求。与传统 CBCT 相比，具有 8 个源和 ASRS 的 ms-CBCT 设计显著改善了图像质量和精度，包括：（1）将杯状伪影从 15%降低至 3.5%；（2）将 CT 亨氏单位值的空间不均匀性从 38.0 降低至 9.2；（3）提高了低对比度物体（亚克力和低密度聚乙烯插件）与水等效背景之间的对比噪声比约 20%；（4）将 HU 值的均方根误差降低了 70%，从 420.1 降低至 124.4。目前用于颌面成像的临床 CBCT 所使用的成像剂量和扫描时间可以通过当前的源和探测器技术来实现。与传统 CBCT 相比，ms-CBCT 设计显著减少了散射，并提高了图像质量和精度。
