Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, 112304 Taipei, Taiwan, ROC.
Institute of Biophotonics, National Yang Ming Chiao Tung University, 112304 Taipei, Taiwan, ROC.
Phys Med Biol. 2024 Jan 30;69(3). doi: 10.1088/1361-6560/ad1a25.
This study developed a prototype for a rotational cone-beam x-ray luminescence computed tomography (CB-XLCT) system, considering its potential application in pre-clinical theranostic imaging. A geometric calibration method applicable to both imaging chains (XL and CT) was also developed to enhance image quality. The results of systematic performance evaluations were presented to assess the feasibility of commercializing XLCT technology. Monte Carlo GATE simulation was performed to determine the optimal imaging conditions for nanophosphor particles (NPs) irradiated by 70 kV x-rays. We acquired a low-dose transmission x-ray tube and designed a prone positioning platform and a rotating gantry, using mice as targets from commercial small animal-CT systems. We then employed the image cross-correlation (ICC) automatic geometric calibration method to calibrate XL and CT images. The performance of the system was evaluated through a series of phantom experiments with a linearity of 0.99, and the contrast-to-noise ratio (CNR) between hydroxyl-apatite (HA) and based epoxy resin is 19.5. The XL images of the CB-XLCT prototype achieved a Dice similarity coefficient (DICE) of 0.149 for a distance of 1 mm between the two light sources. Finally, the final XLCT imaging results were demonstrated using the Letter phantoms with NPs. In summary, the CB-XLCT prototype developed in this study showed the potential to achieve high-quality imaging with acceptable radiation doses for small animals. The performance of CT images was comparable to current commercial machines, while the XL images exhibited promising results in phantom imaging, but further efforts are needed for biomedical applications.
本研究开发了一种旋转锥形束 X 射线发光计算机断层成像（CB-XLCT）系统原型，考虑到其在临床前治疗成像中的潜在应用。还开发了一种适用于成像链（XL 和 CT）的几何校准方法，以提高图像质量。呈现了系统性能评估的结果，以评估商业化 XLCT 技术的可行性。通过蒙特卡罗 GATE 模拟确定了用 70kV X 射线照射纳米荧光粉（NPs）的最佳成像条件。我们获取了低剂量透射 X 射线管，并使用商用小动物 CT 系统的老鼠作为目标，设计了一个俯卧定位平台和一个旋转龙门架。然后，我们采用图像互相关（ICC）自动几何校准方法来校准 XL 和 CT 图像。通过一系列具有线性度为 0.99 的体模实验评估了系统的性能，羟基磷灰石（HA）和基础环氧树脂之间的对比噪声比（CNR）为 19.5。CB-XLCT 原型的 XL 图像在两个光源之间距离为 1mm 时达到了 0.149 的骰子相似系数（DICE）。最后，使用带有 NPs 的字母体模展示了最终的 XLCT 成像结果。总之，本研究开发的 CB-XLCT 原型有望在小动物成像中实现高质量成像和可接受的辐射剂量。CT 图像的性能与当前商用机器相当，而 XL 图像在体模成像中显示出了有前途的结果，但在生物医学应用中还需要进一步努力。
