Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada.
Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
Can Assoc Radiol J. 2020 Feb;71(1):68-74. doi: 10.1177/0846537119885680. Epub 2020 Jan 22.
Cone-beam computed tomography (CBCT) in interventional radiology allows volumetric imaging with open patient access. This work aimed to assess radiation dose metrics of CBCT in simulated image-guided retrograde gastrostomy (IGRG) tube insertions in pediatric anthropomorphic phantoms and to compare them to measured radiation dose metrics obtained using fluoroscopy during clinical IGRG tube insertions in children.
Radiation dose indices obtained from radiation dose structured reports of fluoroscopic IGRG tube insertions were retrospectively evaluated in a consecutive cohort of 30 children. Dose indices were fractionated into 3 clinical stages for each procedure (, , and ). These 3 stages in 30 patients (3 × 30 = 90 patient stages) were compared to dose indices measured from 4 CBCT acquisition protocols acquired in pediatric phantoms.
The mean proportion of radiation dose during planning, insertion, and confirmation was 35%, 38% and 27%, with mean reference-point air kerma (range) measured to be 1.0 (0.02-6.0) mGy, 0.9 (0.03-4.1) mGy, and 0.7 (0.04-3.7) mGy, respectively. Cone-beam computed tomography dose varied greatly depending on technical parameters and protocol selection, ranging from 0.7 to 39.3 mGy. In 19% of patient stages, the most dose-sparing CBCT protocol evaluated on phantoms delivered less radiation than the radiation dose indices recorded from patient's fluoroscopy.
From a dosimetric perspective, radiation delivered in CBCT can vary widely, yet can be appreciably low. With appropriate CBCT protocol selection, the radiation dose delivered may be sufficiently low to warrant consideration for use, if clinically needed during difficult IGRG tube insertions, and satisfy the interventionalist's benefit-risk assessment.
介入放射学中的锥形束计算机断层扫描（CBCT）允许开放患者通道进行容积成像。本研究旨在评估模拟引导逆行胃造口术（IGRG）管插入中 CBCT 的辐射剂量指标，并将其与儿童临床 IGRG 管插入中透视获得的测量辐射剂量指标进行比较。
回顾性评估了连续 30 例儿童的透视引导 IGRG 管插入的辐射剂量结构报告中获得的辐射剂量指标。将剂量指标分为每个程序的 3 个临床阶段（、和）。将这 30 个患者的 3 个阶段（3×30=90 个患者阶段）与在儿科模型中获得的 4 个 CBCT 采集方案中测量的剂量指标进行比较。
计划、插入和确认期间的平均辐射剂量比例分别为 35%、38%和 27%，测量的参考点空气比释动能（范围）分别为 1.0（0.02-6.0）mGy、0.9（0.03-4.1）mGy 和 0.7（0.04-3.7）mGy。CBCT 剂量随技术参数和协议选择而变化很大，范围从 0.7 到 39.3 mGy。在 19%的患者阶段，在模型上评估的最节省剂量的 CBCT 方案提供的辐射量低于从患者透视获得的辐射剂量指标。
从剂量学角度来看，CBCT 中提供的辐射量差异很大，但可以明显降低。通过适当的 CBCT 协议选择，如果在困难的 IGRG 管插入过程中临床需要，并且满足介入医生的受益风险评估，可以考虑使用，因为其提供的辐射剂量可能足够低。
