A New PET Scanner with Semiconductor Detectors Enables Better Identification of Intratumoral Inhomogeneity
A New PET Scanner with Semiconductor Detectors Enables Better Identification of Intratumoral Inhomogeneity
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DOI：
10.2967/jnumed.108.054833
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发表时间：
2009-01-01
影响因子：
9.3
通讯作者：
Tamaki, Nagara
中科院分区：
文献类型：
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作者：
Shiga, Tohru;Morimoto, Yuichi;Tamaki, Nagara
放射自显影方法显示各种实体瘤中的瘤内不均匀性。评估肿瘤内的不均匀性变得越来越重要。然而，由于低空间分辨率和高散射噪声，在临床环境中难以检测肿瘤内的不均匀性。我们开发了一种新的PET系统与碲化镉半导体探测器，以提供高空间分辨率和低散射噪声的图像。对体模图像和患者图像进行分析，以评估肿瘤内的不均匀性。研究方法：本研究使用具有6 mm直径冷蝶骨缺损的冷点体模、浓度调整为1：2的双圆柱体模和“H”形热体模进行。它们被水包围着。对鼻咽癌患者的体模图像和F-18-FDG PET图像与常规锗酸铋PET图像进行比较。测量体模的轮廓曲线作为峰谷比以定义对比度。在患者的图像上评价瘤内不均匀性和肿瘤边缘清晰度。结果如下：对于直径为6 mm的冷蝶骨体模，使用半导体PET扫描仪获得的对比度（1.53）比使用传统扫描仪获得的对比度（1.20）高28%。对于双圆柱体模，用半导体PET扫描仪获得的对比度（1.43）比用传统扫描仪获得的对比度（1.13）高27%。同样，1 mm热棒之间的2 mm冷区域仅由新的PET扫描仪识别，而不是由传统扫描仪识别。在10名患者中，新的PET扫描仪比传统扫描仪更详细地识别了6名患者的瘤内不均匀性。新的PET扫描仪获得的图像上的肿瘤边缘比传统扫描仪获得的图像上的肿瘤边缘更清晰。结论：这些体模和临床研究表明，这种新的PET扫描仪有可能更好地识别肿瘤内的不均匀性，可能是因为它的高空间分辨率和低散射噪声。
An autoradiography method revealed intratumoral inhomogeneity in various solid tumors. It is becoming increasingly important to estimate intratumoral inhomogeneity. However, with low spatial resolution and high scatter noise, it is difficult to detect intratumoral inhomogeneity in clinical settings. We developed a new PET system with CdTe semiconductor detectors to provide images with high spatial resolution and low scatter noise. Both phantom images and patients' images were analyzed to evaluate intratumoral inhomogeneity. Methods: This study was performed with a cold spot phantom that had 6-mm-diameter cold sphenoid defects, a dual-cylinder phantom with an adjusted concentration of 1:2, and an "H"-shaped hot phantom. These were surrounded with water. Phantom images and F-18-FDG PET images of patients with nasopharyngeal cancer were compared with conventional bismuth germanate PET images. Profile curves for the phantoms were measured as peak-to-valley ratios to define contrast. Intratumoral inhomogeneity and tumor edge sharpness were evaluated on the images of the patients. Results: The contrast obtained with the semiconductor PET scanner (1.53) was 28% higher than that obtained with the conventional scanner (1.20) for the 6-mm-diameter cold sphenoid phantom. The contrast obtained with the semiconductor PET scanner (1.43) was 27% higher than that obtained with the conventional scanner (1.13) for the dual-cylinder phantom. Similarly, the 2-mm cold region between 1-mm hot rods was identified only by the new PET scanner and not by the conventional scanner. The new PET scanner identified intratumoral inhomogeneity in more detail than the conventional scanner in 6 of 10 patients. The tumor edge was sharper on the images obtained with the new PET scanner than on those obtained with the conventional scanner. Conclusion: These phantom and clinical studies suggested that this new PET scanner has the potential for better identification of intratumoral inhomogeneity, probably because of its high spatial resolution and low scatter noise.