Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
Department of Gastroenterology, Johns Hopkins School of Medicine, Baltimore, Maryland.
Int J Radiat Oncol Biol Phys. 2018 Jul 1;101(3):640-645. doi: 10.1016/j.ijrobp.2018.02.024. Epub 2018 Mar 2.
To test the feasibility and safety of injecting a high-contrast hydrogel marker at the head of the pancreas (HOP) and duodenum interface and assesses the marker visibility on cone beam computed tomography (CBCT) to localize this important boundary during image guided radiation therapy in a porcine model.
This was a 2-stage study. The feasibility/visibility stage evaluated the ability to place the hydrogel using endoscopic ultrasound guidance on 8 swine (4 euthanized at post-injection day 8, 4 euthanized at post-injection day 22) and assessed the quality of visibility of the marked location on CBCT in the longer-surviving group. The risk assessment stage evaluated the toxicity of targeted intrapancreatic injections (3 swine) and intramural duodenal wall injections (3 swine) to assess toxicity of a misplaced hydrogel injection. All swine underwent postmortem examination and histopathologic studies.
The HOP-duodenum interface was successfully marked using hydrogel in 6 of the 8 swine. Histopathologic examination of the 6 successful hydrogel injections showed mild/minimal (4 cases) or moderate (2 cases) reactive inflammation isolated to the injection site. Of the 4 swine survived to 22 days, 3 demonstrated successful hydrogel placement at the HOP-duodenum interface, and this marked location was clearly visible for positional guidance on CBCT. There was no evidence of pancreatitis or duodenal toxicity in the swine undergoing targeted intrapancreatic or intramural duodenum injections for the risk assessment stage.
We demonstrate the feasibility and safety of injecting a hydrogel marker to highlight the HOP-duodenum interface that has acceptable visibility on CBCT. This technique, translated to humans, enables on-board visualization of this important boundary between the radiation target and dose-limiting, radiosensitive duodenum, facilitating efforts to safely deliver dose-escalated radiation therapy.
测试在胰腺头部（HOP）和十二指肠交界处注射高对比度水凝胶标记物的可行性和安全性，并评估该标记物在锥形束计算机断层扫描（CBCT）上的可见度，以便在猪模型中进行图像引导放射治疗时定位这个重要的边界。
这是一个两阶段的研究。可行性/可见性阶段评估了使用内镜超声引导在 8 头猪（4 头在注射后第 8 天处死，4 头在注射后第 22 天处死）中放置水凝胶的能力，并评估了在存活时间较长的组中 CBCT 上标记位置的可见质量。风险评估阶段评估了靶向胰腺内注射（3 头猪）和壁内十二指肠壁注射（3 头猪）的毒性，以评估误置水凝胶注射的毒性。所有猪都进行了尸检和组织病理学研究。
在 8 头猪中，有 6 头成功地用水凝胶标记了 HOP-十二指肠交界处。对 6 例成功的水凝胶注射的组织病理学检查显示，注射部位有轻度/最小（4 例）或中度（2 例）反应性炎症。在存活至 22 天的 4 头猪中，有 3 头在 HOP-十二指肠交界处成功放置了水凝胶，并且在 CBCT 上可以清楚地看到这个标记位置，以便进行定位引导。在风险评估阶段，对胰腺内或壁内十二指肠进行靶向注射的猪没有胰腺炎或十二指肠毒性的证据。
我们证明了注射水凝胶标记物以突出 HOP-十二指肠交界处的可行性和安全性，该标记物在 CBCT 上具有可接受的可见度。这项技术，如果应用于人类，可以使辐射靶区和剂量限制、辐射敏感的十二指肠之间的这个重要边界在治疗过程中实时可视化，从而有助于安全地实施大剂量放疗。
