Lim Joon Daryl, Berlangieri Alexandra, Harris Benjamin, Tacey Mark, O'Meara Rachel, Pitt Brent, Viotto Angela, Brown Kerryn, Schneider Michal, Lawrentschuk Nathan, Sengupta Shomik, Berry Colleen, Jenkins Trish, Chao Michael, Wada Morikatsu, Foroudi Farshad, Khoo Vincent
Olivia Newton John Cancer Center, Radiation Oncology, 145 Studley Rd, Heidelberg, Victoria 3084, Australia.
Monash University, Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, Nursing and Health Sciences, Wellington Rd, Clayton, Victoria 3800, Australia.
Phys Imaging Radiat Oncol. 2021 Feb 6;17:77-83. doi: 10.1016/j.phro.2021.01.008. eCollection 2021 Jan.
Image-guidance with fiducials has been shown to improve pelvic radiotherapy outcome. However, bladder fiducials using ethiodized oil (EO) alone can disperse widely, and gold causes Computed Tomography scan (CT) metal artifacts. The study's purpose was to investigate the ability to deliver EO-tissue glue fiducials and compare them to gold for bladder radiotherapy image guidance.
A fluid-filled porcine bladder model was used to assess the ability to cystoscopically inject visible EO glue fiducials into the submucosa. We then transferred the bladders into a porcine pelvis for imaging and compared them to gold fiducials using CT, Cone Beam CT (CBCT), and kilovoltage (KV) planar views. A tissue-equivalent phantom was utilized to analyze the CT number Hounsfield Unit (HU) characteristics and artifacts of the glue and gold fiducials. Percentile ranges and normal tissue voxel percentages of the subsequent CT number voxel histogram from a 2 cm sphere surrounding the fiducial was used to characterize the artifact
We successfully delivered all EO glue fiducials into the porcine bladders as discrete fiducials. They were well seen on CT, CBCT, and KV imaging. The glue fiducials had lower CT number values, but less CT number spread of the voxel percentile ranges consistent with the diminished contrast and less artifact than gold. The glue fiducial types had similar CT number characteristics.
This study has shown that EO glue fiducials can be delivered with online visualization qualities comparable to gold fiducials without metal-related artifacts.
已证明使用基准标记的图像引导可改善盆腔放疗效果。然而，单独使用乙碘油（EO）的膀胱基准标记可能会广泛分散，而金会导致计算机断层扫描（CT）金属伪影。本研究的目的是研究输送EO - 组织胶水基准标记的能力，并将其与用于膀胱放疗图像引导的金基准标记进行比较。
使用充满液体的猪膀胱模型评估通过膀胱镜将可见的EO胶水基准标记注射到黏膜下层的能力。然后将膀胱转移到猪骨盆中进行成像，并使用CT、锥形束CT（CBCT）和千伏（KV）平面视图将其与金基准标记进行比较。利用组织等效体模分析胶水和金基准标记的CT值亨氏单位（HU）特征及伪影。使用围绕基准标记的2厘米球体的后续CT值体素直方图的百分位数范围和正常组织体素百分比来表征伪影。
我们成功地将所有EO胶水基准标记作为离散的基准标记输送到猪膀胱中。它们在CT、CBCT和KV成像上清晰可见。胶水基准标记的CT值较低，但体素百分位数范围的CT值分布较窄，与对比度降低一致，且伪影比金少。胶水基准标记类型具有相似的CT值特征。
本研究表明，EO胶水基准标记可以在具有与金基准标记相当的在线可视化质量的情况下输送，且无金属相关伪影。
