University College London Cancer Institute, University College London, London, United Kingdom.
University College London Hospitals NHS Foundation Trust, London, United Kingdom.
Br J Radiol. 2022 Feb 1;95(1130):20210594. doi: 10.1259/bjr.20210594. Epub 2021 Nov 16.
To determine the feasibility of using radiopaque (RO) beads as direct tumour surrogates for image-guided radiotherapy (IGRT) in patients with liver tumours after transarterial chemoembolisation (TACE).
A novel vandetanib-eluting RO bead was delivered via TACE as part of a first-in-human clinical trial in patients with either hepatocellular carcinoma or liver metastases from colorectal cancer. Following TACE, patients underwent simulated radiotherapy imaging with four-dimensional computed tomography (4D-CT) and cone-beam CT (CBCT) imaging. RO beads were contoured using automated thresholding, and feasibility of matching between the simulated radiotherapy planning dataset (AVE-IP image from 4D data) and CBCT scans assessed. Additional kV, MV, helical CT and CBCT images of RO beads were obtained using an in-house phantom. Stability of RO bead position was assessed by comparing 4D-CT imaging to CT scans taken 6-20 days following TACE.
Eight patients were treated and 4D-CT and CBCT images acquired. RO beads were visible on 4D-CT and CBCT images in all cases and matching successfully performed. Differences in centre of mass of RO beads between CBCT and simulated radiotherapy planning scans (AVE-IP dataset) were 2.0 mm mediolaterally, 1.7 mm anteroposteriorally and 3.5 mm craniocaudally. RO beads in the phantom were visible on all imaging modalities assessed. RO bead position remained stable up to 29 days post TACE.
RO beads are visible on IGRT imaging modalities, showing minimal artefact. They can be used for on-set matching with CBCT and remain stable over time.
The role of RO beads as fiducial markers for stereotactic liver radiotherapy is feasible and warrants further exploration as a combination therapy approach.
确定经肝动脉化疗栓塞术（TACE）后，放射性不透射线（RO）珠能否作为肝肿瘤患者图像引导放疗（IGRT）的直接肿瘤替代物。
一种新型的凡德他尼洗脱 RO 珠通过 TACE 给药，作为首例人体临床试验的一部分，该试验入组了肝细胞癌或结直肠癌肝转移患者。TACE 后，患者接受了四维计算机断层扫描（4D-CT）和锥形束 CT（CBCT）模拟放疗成像。使用自动阈值法勾画 RO 珠，并评估模拟放疗计划数据集（4D 数据中的 AVE-IP 图像）与 CBCT 扫描之间的匹配可行性。使用内部体模获得了 RO 珠的额外千伏（kV）、兆伏（MV）、螺旋 CT 和 CBCT 图像。通过比较 4D-CT 成像与 TACE 后 6-20 天的 CT 扫描，评估 RO 珠位置的稳定性。
共 8 例患者接受了治疗并采集了 4D-CT 和 CBCT 图像。所有病例在 4D-CT 和 CBCT 图像上均可见 RO 珠，且成功进行了匹配。CBCT 与模拟放疗计划扫描（AVE-IP 数据集）中 RO 珠质心的差异分别为 2.0mm 内外侧、1.7mm 前后向和 3.5mm 头足向。在评估的所有成像方式上，体模中的 RO 珠均可见。RO 珠的位置在 TACE 后 29 天内保持稳定。
RO 珠在 IGRT 成像方式上可见，其伪影最小。它们可用于与 CBCT 一起进行起始匹配，并且随着时间的推移保持稳定。
RO 珠作为立体定向肝放疗的基准标记物是可行的，值得进一步探索作为联合治疗方法。
