Dobbeleir Andre, Ham Hamphrey, Goethals Ingeborg, Keppens Johan, D'Asseler Yves, Van de Wiele Christophe
Department of Nuclear Medicine, University Hospital Ghent, 9000 Ghent, Belgium.
Nucl Med Commun. 2010 Mar;31(3):190-4. doi: 10.1097/MNM.0b013e3283360194.
The aim of the study was to find out whether in [F]fluoro-2-deoxy-D-glucose positron emission tomography (F-18 FDG-PET) performed in children in our department, the number of counts were sufficiently high to guarantee optimal image quality.
Phantom data with negative and positive lesions were acquired with an increasing count density and the relationship between image quality and counts per voxel was analyzed. On PET images obtained in 28 children aged 4-17 years and using a standard administered activity of 6.5 MBq/kg with a minimum of 74 MBq, the maximum counts per voxel in 10 regions of interest were noted and compared with those obtained on phantoms.
Phantom data showed clearly the effect of higher count on image quality. Moreover, when high counts were available, reconstruction could be done using 2 mm voxel size, which improved the quality of the images further. In children, the counts per voxel in all the regions of interest, with the exception of the brain, were at a level of suboptimal image quality.
By following the official guidelines, the counts per voxel observed in children with our gadolinium oxyorthosilicate-PET system were lower than the minimal required to produce optimal quality images. More efficient PET systems or higher F-18 FDG dose or increasing the acquisition time or combination of these factors are needed to improve the image quality and lesion detection.
本研究旨在查明在我院对儿童进行的[氟] - 2 - 脱氧 - D - 葡萄糖正电子发射断层扫描（F - 18 FDG - PET）中，计数数量是否足够高以保证最佳图像质量。
采集具有阴性和阳性病变的模体数据，计数密度逐渐增加，并分析图像质量与每体素计数之间的关系。在对28名4至17岁儿童进行的PET图像上，使用6.5 MBq/kg的标准给药活度且最低74 MBq，记录10个感兴趣区域中每体素的最大计数，并与模体上获得的计数进行比较。
模体数据清楚地显示了较高计数对图像质量的影响。此外，当有高计数时，可以使用2毫米体素大小进行重建，这进一步提高了图像质量。在儿童中，除大脑外，所有感兴趣区域的每体素计数都处于次优图像质量水平。
按照官方指南，使用我们的正硅酸钆 - PET系统在儿童中观察到的每体素计数低于产生最佳质量图像所需的最低计数。需要更高效的PET系统、更高的F - 18 FDG剂量、增加采集时间或这些因素的组合来提高图像质量和病变检测能力。
