Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri.
Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Missouri.
Comp Med. 2021 Apr 1;71(2):116-122. doi: 10.30802/AALAS-CM-20-000089. Epub 2021 Mar 11.
CT (computerized tomography) is a necessary imaging modality for cancer staging and disease monitoring. Rodent models of cancer are commonly studied prior to human clinical trials, but CT in rodents can be difficult due to their small size and constant movement, which necessitates general anesthesia. Because microCT equipment is not always available, clinical CT may be a viable alternative. Limitations of microCT and clinical CT include biosecurity, anesthesia to limit image distortion due to motion, and cost. To address several of these constraints, we created a 3D-printed apparatus that accommodated simultaneous imaging of as many as 9 rats under gas anesthesia. Rats were anesthetized in series and placed in a 3 × 3 arrangement. To assess differences in attenuation between individual chambers and rows or columns in the device, we first imaged a standardized phantom plug as a control. We hypothesized that attenuation of specific rat organs would not be affected regardless of the location or position in the 3D-printed device. Four organs-liver, kidney, femur, and brain-were evaluated in 9 rats. For both the phantom and kidneys, statistically significant, but clinically negligible, effects on attenuation were noted between rows but not between columns. We attribute this finding to the absence of a top layer of the apparatus, which thus created asymmetric attenuation and beam hardening through the device. This apparatus allowed us to successfully image 9 rats simultaneously in a clinical CT machine, with negligible effects on attenuation. Planned improvements in this apparatus include completely enclosed versions for biosecure imaging.
CT（计算机断层扫描）是癌症分期和疾病监测的必要成像方式。在进行人类临床试验之前，通常会在癌症啮齿动物模型上进行研究，但由于啮齿动物体型小且不断运动，因此 CT 检查较为困难，这需要进行全身麻醉。由于并非总是有微 CT 设备，因此临床 CT 可能是一种可行的替代方法。微 CT 和临床 CT 的局限性包括生物安全性、麻醉以限制因运动导致的图像失真以及成本。为了解决其中的一些限制，我们创建了一个 3D 打印设备，可在气体麻醉下同时对多达 9 只大鼠进行成像。大鼠被连续麻醉并以 3×3 的方式放置。为了评估个体腔室之间以及设备中的行或列之间的衰减差异，我们首先使用标准的幻影插件作为对照进行成像。我们假设，无论在 3D 打印设备中的位置如何，特定大鼠器官的衰减都不会受到影响。在 9 只大鼠中评估了四个器官：肝脏、肾脏、股骨和大脑。对于幻影和肾脏，我们注意到在行之间存在但不在列之间存在统计学显著但临床可忽略的衰减影响。我们将这一发现归因于设备缺少顶层，这导致了设备内部的衰减和束硬化不对称。该设备使我们能够成功地在临床 CT 机上同时对 9 只大鼠进行成像，而衰减的影响可忽略不计。该设备的改进计划包括用于生物安全成像的完全封闭版本。
