Department of Radiology, Takai Hospital, Nara 632-0006, Japan.
J Radiat Res. 2010;51(2):157-64. doi: 10.1269/jrr.09063. Epub 2009 Dec 1.
We assessed the usefulness of PET/CT images to determine the target volume in radiotherapy planning by evaluating the standardized uptake value (SUV). We evaluated the imaging conditions and image-reconstruction conditions of PET/CT useful for treatment planning by collecting (18)F-FDG images of acrylic spheres (10-48 mm in diameter) in a phantom. The (18)F-FDG concentration in the spheres was 10-fold higher than that of the phantom. The contours were delineated according to the SUV by the threshold and regions of interest (ROI) methods. Comparisons of two- and three-dimensional (2D and 3D) acquisition images indicated that the sharpness and quantitative qualities of the sphere boundaries were better in the former than in the latter. In the extraction of outlines using the SUV, outlines obtained at an SUV of 40-50% of the maximum agreed well with the actual acrylic sphere size. 2D acquisition images are more suitable for delineating target volume contours, although 3D acquisition images are more popular in diagnostic imaging. An SUV of 40-50% of the maximum is suggested to be appropriate for GTV contouring of sphere tumors with homogenously distributed (18)F-FDG.
我们通过评估标准化摄取值（SUV）来评估 PET/CT 图像在放疗计划中的靶区确定的有用性。我们通过在体模中收集（18）F-FDG 标记的丙烯酸球（直径 10-48mm）的图像来评估对治疗计划有用的 PET/CT 成像条件和图像重建条件。球体中的（18）F-FDG 浓度比体模高 10 倍。根据 SUV 通过阈值和感兴趣区域（ROI）方法勾画轮廓。二维（2D）和三维（3D）采集图像的比较表明，前者的球体边界的清晰度和定量质量优于后者。在使用 SUV 提取轮廓时，SUV 为最大值的 40-50%的轮廓与实际丙烯酸球的尺寸吻合较好。2D 采集图像更适合勾画靶区轮廓，尽管 3D 采集图像在诊断成像中更为流行。对于（18）F-FDG 均匀分布的球体肿瘤，建议 SUV 取最大值的 40-50%进行 GTV 勾画。
