Division of Interventional Radiology, Department of Radiology, University of Washington, Seattle, Washington.
Division of Medical Physics, Department of Radiology, University of Washington, Seattle, Washington.
Int J Radiat Oncol Biol Phys. 2018 Jun 1;101(2):358-365. doi: 10.1016/j.ijrobp.2018.01.116. Epub 2018 Feb 9.
To prospectively assess the threshold dose for objective response of hepatocellular carcinoma (HCC), using Y internal pair-production positron emission tomography (PET) to quantify the radiation dose delivered to hepatic tumors after radioembolization.
A prospective study was performed under institutional review board approval from 2012 to 2014. Thirty-five patients with primary and secondary liver tumors undergoing Y treatment were recruited. Eight patients did not meet inclusion criteria, and 27 patients with HCC were included for analysis. Time-of-flight PET imaging was performed immediately after radioembolization and voxel values converted into Y activity. The radioembolization dose was calculated from PET images, and image segmentation was performed with volumetric analysis of dose deposition within tumors. Radiographic response was assessed on follow-up imaging.
Treated HCC showed 84% objective response, 11% stable disease, and 5% progressive disease according to modified RECIST 1.1 response criteria. Responders had a higher median Y tumor dose than nonresponders (225 Gy vs 83 Gy, P < .01). Logistic regression models show tumor dose (P = .002) strongly predicted objective response. All nonresponders had tumor dose <200 Gy. No statistical difference for patient age, tumor volume, multifocal or extrahepatic disease, portal vein invasion, or injected Y activity was found between responders and nonresponders.
Hepatocellular carcinoma that resulted in objective response after radioembolization had a greater median tumor dose of 225 Gy, compared with 83 Gy in nonresponders. Delivered tumor dose can be assessed by PET and significantly impacts treatment response in HCC.
使用 Y 内符合放射性核素正电子发射断层扫描（PET）定量测量肝肿瘤在放射性栓塞后接受的辐射剂量，前瞻性评估肝细胞癌（HCC）客观反应的阈值剂量。
本前瞻性研究于 2012 年至 2014 年在机构审查委员会的批准下进行。招募了 35 名接受 Y 治疗的原发性和继发性肝肿瘤患者。8 名患者不符合纳入标准，27 名 HCC 患者纳入分析。放射性栓塞后立即进行飞行时间 PET 成像，并将体素值转换为 Y 活性。根据 PET 图像计算放射性栓塞剂量，并通过肿瘤内剂量沉积的容积分析进行图像分割。根据随访成像评估放射学反应。
根据改良 RECIST 1.1 反应标准，治疗后的 HCC 客观反应率为 84%，稳定疾病率为 11%，进展疾病率为 5%。根据 RECIST 1.1 标准，应答者的中位 Y 肿瘤剂量高于无应答者（225Gy 比 83Gy，P<.01）。逻辑回归模型显示肿瘤剂量（P=.002）强烈预测客观反应。所有无应答者的肿瘤剂量均<200Gy。应答者和无应答者之间的患者年龄、肿瘤体积、多灶性或肝外疾病、门静脉侵犯或注入的 Y 活性无统计学差异。
与无应答者的 83Gy 相比，放射性栓塞后导致客观反应的 HCC 的中位肿瘤剂量更高，为 225Gy。通过 PET 可评估肿瘤内的输送剂量，并且对 HCC 的治疗反应有显著影响。
