A Novel Method to Extend a Partial-Body CT for the Reconstruction of Dose to Organs beyond the Scan Range
A Novel Method to Extend a Partial-Body CT for the Reconstruction of Dose to Organs beyond the Scan Range
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DOI：
10.1667/rr14999.1
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发表时间：
2018-06-01
影响因子：
3.4
通讯作者：
Lee, Choonsik
中科院分区：
文献类型：
--
作者：
Kuzmin, Gleb A.;Mille, Matthew M.;Lee, Choonsik
流行病学调查是评估放射治疗后迟发效应风险的重要方法，而器官剂量学是这种分析的关键部分。计算机断层扫描（CT）图像，如果可用的话，可以是个性化剂量测定的宝贵资源，因为它们描述了患者的特定解剖结构。然而，出于放射治疗计划目的而采集的CT图像仅覆盖靶体积附近的身体部分，而对于流行病学，感兴趣的是可能位于扫描范围之外的更远的正常组织。为了应对这一挑战，我们开发了一种新的方法，称为解剖预测扩展（APE），使用基于身高和体重与患者匹配的计算人体模型的图像来扩展部分身体CT图像堆栈。为了测试我们的方法，我们创建了五个APE幻影从胸部和腹部图像提取的胸部-腹部-骨盆（CAP）CT扫描的五名患者。计算了在参考计算体模（如果没有CT图像可用，则假设患者几何结构）、APE体模（给定部分身体患者CT的患者-体模混合）和完整患者CAP CT扫描（地面实况）上计划的简单胸部和前列腺辐照的器官剂量。APE体模和患者CAP CT扫描导致完全包含在用于构建APE的部分体CT中的器官的剂量测定几乎相同。在胸部和前列腺病例中，参考体模中这些相同器官的计算剂量分别相差20%和52%。对于扫描覆盖范围外的器官，参考体模显示平均剂量差异为31%（胸部病例）和41%（前列腺病例）。对于APE体模，这些值为26%（胸部）和17%（前列腺）。APE方法结合了患者和体模图像，以改善扫描范围内外的器官剂量测定。我们打算使用APE方法来估计治疗野周围器官的剂量;然而，这种方法具有很大的推广性，有许多潜在的应用。(C)2018辐射研究学会
Epidemiological investigation is an important approach to assessing the risk of late effects after radiotherapy, and organ dosimetry is a crucial part of such analysis. Computed tomography (CT) images, if available, can be a valuable resource for individualizing the dosimetry, because they describe the specific anatomy of the patient. However, CT images acquired for radiation treatment planning purposes cover only a portion of the body near the target volume, whereas for epidemiology, the interest lies in the more distant normal tissues, which may be located outside the scan range. To address this challenge, we developed a novel method, called the Anatomically Predictive Extension (APE), to extend a partial-body CT image stack using images of a computational human phantom matched to the patient based on their height and weight. To test our method, we created five APE phantoms from chest and abdominal images extracted from the chest-abdomen-pelvis (CAP) CT scans of five patients. Organ doses were calculated for simple chest and prostate irradiations that were planned on the reference computational phantom (assumed patient geometry if no CT images are available), APE phantoms (patient-phantom hybrid given a partial-body patient CT) and full patient CAP CT scans (ground truth). The APE phantoms and patient CAP CT scans resulted in nearly identical dosimetry for those organs that were fully included in the partial-body CT used to construct the APE. The calculated doses to these same organs in the reference phantoms differed by up to 20% and 52% for the chest and prostate cases, respectively. For organs outside the scan coverage, the reference phantom showed, on average, dose differences of 31% (chest case) and 41% (prostate case). For the APE phantoms, these values were 26% (chest) and 17% (prostate). The APE method combines patient and phantom images to improve organ dosimetry both inside and outside the scan range. We intend to use the APE method for estimating dose for organs peripheral to the treatment fields; however, this method is quite generalizable with many potential applications. (C) 2018 by Radiation Research Society