Objective

To compare radioembolization treatment zone volumes from mapping cone beam CT (CBCT) versus planning CT/MRI and to model their impact on dosimetry.

Methods

Y90 cases were retrospectively identified in which intra-procedural CBCT angiograms were performed. Segmental and lobar treatment zone volumes were calculated with semi-automated contouring using Couinaud venous anatomy (planning CT/MRI) or tumor angiosome enhancement (CBCT). Differences were compared with a Wilcoxon signed-rank test. Treatment zone-specific differences in segmental volumes by volumetric method were also calculated and used to model differences in delivered dose using medical internal radiation dosimetry (MIRD) at 200 and 120 Gy targets. Anatomic, pathologic, and technical factors likely affecting segmental volumes by volumetric method were evaluated.

Results

Forty segmental and 48 lobar CBCT angiograms and corresponding planning CT/MRI scans were included. Median Couinaud- and CBCT-derived segmental volumes were 281 and 243 mL, respectively (p = 0.005). Differences between Couinaud and CBCT lobar volumes (right, left) were not significant (p = 0.24, p = 0.07). Couinaud overestimated segmental volumes in 28 cases by a median of 98 mL (83%) and underestimated in 12 cases by median 69 mL (20%). At a 200 Gy dose target, Couinaud estimates produced median delivered doses of 367 and 160 Gy in these 28 and 12 cases. At a 120 Gy target, Couinaud produced doses of 220 and 96 Gy. Proximal vs. distal microcatheter positioning, variant arterial anatomy, and tumor location on or near segmental watersheds were leading factors linked to volumetric differences.

Conclusion

Use of CBCT-based volumetry may allow more accurate, personalized dosimetry for segmental Y90 radioembolization.

中文翻译：

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传统的肝体积测量可能导致不准确的段式 Ytrium-90 辐射剂量测定

客观的

比较来自映射锥形束 CT (CBCT) 与计划 CT/MRI 的放射栓塞治疗区体积，并模拟它们对剂量学的影响。

方法

对 Y90 病例进行了回顾性鉴定，其中进行了术中 CBCT 血管造影。使用 Couinaud 静脉解剖（计划 CT/MRI）或肿瘤血管增强 (CBCT) 通过半自动轮廓绘制计算节段和肺叶治疗区体积。将差异与 Wilcoxon 符号秩检验进行比较。还计算了体积法治疗区特定的节段体积差异，并将其用于模拟使用医疗内部辐射剂量测定 (MIRD) 在 200 和 120 Gy 目标下传递剂量的差异。评估了体积法可能影响节段体积的解剖学、病理学和技术因素。

结果

包括 40 个节段性和 48 个肺叶 CBCT 血管造影以及相应的计划 CT/MRI 扫描。中位数 Couinaud 和 CBCT 衍生的节段体积分别为 281 和 243 mL ( p  = 0.005)。Couinaud 和 CBCT 肺叶体积（右、左）之间的差异不显着（p  = 0.24，p = 0.07）。Couinaud 高估了 28 个病例的节段体积，中位数为 98 mL (83%)，低估了 12 个病例的中位数 69 mL (20%)。在 200 Gy 的剂量目标下，Couinaud 估计在这 28 和 12 例中产生的中位剂量分别为 367 和 160 Gy。在 120 Gy 的目标下，Couinaud 产生了 220 和 96 Gy 的剂量。近端与远端微导管定位、不同的动脉解剖结构以及节段分水岭上或附近的肿瘤位置是与体积差异相关的主要因素。

结论

使用基于 CBCT 的容积测量可能允许更准确、个性化的剂量测定用于节段性 Y90 放射栓塞。