Patient-specific dosimetry for 131I thyroid cancer therapy using 124I PET and 3-dimensional-internal dosimetry (3D-ID) software.
Patient-specific dosimetry for 131I thyroid cancer therapy using 124I PET and 3-dimensional-internal dosimetry (3D-ID) software.
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发表时间：
2004-08
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通讯作者：
G. Sgouros;K. Kolbert;A. Sheikh;K. Pentlow;Edward Mun;A. Barth;R. Robbins;S. Larson
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作者：
G. Sgouros;K. Kolbert;A. Sheikh;K. Pentlow;Edward Mun;A. Barth;R. Robbins;S. Larson
与传统的全器官、基于S因子的剂量测定相比，三维（3D）患者特异性剂量测定更好地解释了放射性核素分布和解剖学患者变异性。然而，其准确性受到作为输入提供的累积活动信息的质量的限制。该输入通常从SPECT和平面成像研究中获得。目的是实施和评价基于PET的、患者特异性的甲状腺癌患者3D剂量测定。方法对15例甲状腺转移癌患者在注射124 I-NaI后7 d内进行3 ~ 4次PET显像。随后，患者根据已确定的临床参数接受（131）I治疗。使用配准的（124）I PET图像进行回顾性剂量测定，这些图像校正了（124）I和（131）I之间的半衰期差异。随着时间的推移，对所得的（131）I等效PET衍生图像进行逐体素积分，以提供单个3D数据集，该数据集代表每例患者累积活动值的空间分布。使用先前开发的软件包多图像分析实用程序（MIAU）进行图像处理和配准。使用软件包3D-内部剂量测定（3D-ID）从累积活动图像集获得吸收剂量图。结果获得了56个肿瘤的吸收剂量空间分布、等剂量线、剂量体积直方图（DVH）和平均吸收剂量估计值。单个肿瘤的平均吸收剂量值范围为1.2至540戈伊。单个肿瘤内的吸收剂量分布广泛，最小值为0.3 Gy，最大值为4，000戈伊。结论基于124 I PET的患者特异性三维剂量测量是可行的，序贯PET可用于获得三维剂量测量的累积放射性图像。
UNLABELLED Compared with conventional, whole-organ, S-factor-based dosimetry, 3-dimensional (3D), patient-specific dosimetry better accounts for radionuclide distribution and anatomic patient variability. Its accuracy, however, is limited by the quality of the cumulated activity information that is provided as input. This input has typically been obtained from SPECT and planar imaging studies. The objective was to implement and evaluate PET-based, patient-specific, 3D dosimetry for thyroid cancer patients. METHODS Three to 4 PET imaging studies were obtained over a 7-d period in 15 patients with metastatic thyroid carcinoma after administration of (124)I-NaI. Subsequently, patients were treated with (131)I on the basis of established clinical parameters. Retrospective dosimetry was performed using registered (124)I PET images that were corrected for the half-life difference between (124)I and (131)I. A voxel-by-voxel integration, over time, of the resulting (131)I-equivalent PET-derived images was performed to provide a single 3D dataset representing the spatial distribution of cumulated activity values for each patient. Image manipulation and registration were performed using Multiple Image Analysis Utility (MIAU), a software package developed previously. The software package, 3D-Internal Dosimetry (3D-ID), was used to obtain absorbed dose maps from the cumulated activity image sets. RESULTS Spatial distributions of absorbed dose, isodose contours, dose-volume histograms (DVHs), and mean absorbed dose estimates were obtained for a total of 56 tumors. Mean absorbed dose values for individual tumors ranged from 1.2 to 540 Gy. The absorbed dose distribution within individual tumors was widely distributed ranging from a minimum of 0.3 to a maximum of 4,000 Gy. CONCLUSION (124)I PET-based, patient-specific 3D dosimetry is feasible, and sequential PET can be used to obtain cumulated activity images for 3D dosimetry.