University Hospital of Heraklion, Medical Physics Department, Stavrakia, Heraklion, Crete, Greece.
Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva, Switzerland.
J Appl Clin Med Phys. 2024 Jul;25(7):e14389. doi: 10.1002/acm2.14389. Epub 2024 May 22.
The aim of this study was to compare the organ doses assessed through a digital phantom-based and a patient specific-based dosimetric tool in adult routine thorax computed tomography (CT) examinations with reference to physical dose measurements performed in anthropomorphic phantoms.
Two Monte Carlo based dose calculation tools were used to assess organ doses in routine adult thorax CT examinations. These were a digital phantom-based dosimetry tool (NCICT, National Cancer Institute, USA) and a patient-specific individualized dosimetry tool (ImpactMC, CT Imaging GmbH, Germany). Digital phantoms and patients were classified in four groups according to their water equivalent diameter (D). Normalized to volume computed tomography dose index (CTDI), organ dose was assessed for lungs, esophagus, heart, breast, active bone marrow, and skin. Organ doses were compared to measurements performed using thermoluminescent detectors (TLDs) in two physical anthropomorphic phantoms that simulate the average adult individual as a male (Alderson Research Labs, USA) and as a female (ATOM Phantoms, USA).
The average percent difference of NCICT to TLD and ImpactMC to TLD dose measurements across all organs in both sexes was 13% and 6%, respectively. The average ± 1 standard deviation in dose values across all organs with NCICT, ImpactMC, and TLDs was ± 0.06 (mGy/mGy), ± 0.19 (mGy/mGy), and ± 0.13 (mGy/mGy), respectively. Organ doses decreased with increasing D in both NCICT and ImpactMC.
Organ doses estimated with ImpactMC were in closer agreement to TLDs compared to NCICT. This may be attributed to the inherent property of ImpactMC methodology to generate phantoms that resemble the realistic anatomy of the examined patient as opposed to NCICT methodology that incorporates an anatomical discrepancy between phantoms and patients.
本研究旨在比较基于数字体模和患者特定的剂量学工具评估的成人常规胸部 CT 检查中的器官剂量，并与人体模型中的物理剂量测量值进行比较。
使用两种基于蒙特卡罗的剂量计算工具来评估常规成人胸部 CT 检查中的器官剂量。这些工具是基于数字体模的剂量学工具（美国国家癌症研究所的 NCICT）和患者特异性个体化剂量学工具（德国 CT 成像有限公司的 ImpactMC）。根据水当量直径（D）将数字体模和患者分为四组。将器官剂量归一化为体积 CT 剂量指数（CTDI），并评估肺、食管、心脏、乳房、活性骨髓和皮肤的剂量。将器官剂量与使用热释光探测器（TLDs）在两个模拟平均成年个体的物理人体模型中进行的测量值进行比较，这两个模型分别是男性（美国 Alderson 研究实验室的 Alderson Research Labs）和女性（美国 ATOM 体模的 ATOM Phantoms）。
在两性中，NCICT 与 TLD 和 ImpactMC 与 TLD 剂量测量值的平均百分比差异分别为 13%和 6%。NCICT、ImpactMC 和 TLDs 中所有器官的剂量值平均值±1 标准差分别为±0.06（mGy/mGy）、±0.19（mGy/mGy）和±0.13（mGy/mGy）。在 NCICT 和 ImpactMC 中，器官剂量随 D 的增加而降低。
与 NCICT 相比，ImpactMC 估计的器官剂量与 TLDs 更吻合。这可能归因于 ImpactMC 方法的固有特性，即生成与受检患者的真实解剖结构相似的体模，而不是 NCICT 方法，该方法在体模和患者之间存在解剖差异。
