Optimization and assessment of quantitative 124I imaging on a Philips Gemini dual GS PET/CT system
Optimization and assessment of quantitative 124I imaging on a Philips Gemini dual GS PET/CT system
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DOI：
10.1007/s00259-009-1099-8
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发表时间：
2009-07-01
影响因子：
9.1
通讯作者：
Flux, Glenn D.
中科院分区：
文献类型：
--
作者：
Gregory, Rebecca A.;Hooker, Claire A.;Flux, Glenn D.
定量I-124 PET成像具有挑战性，因为I-124具有复杂的衰变方案。本研究针对I-124对Philips Gemini双GS PET/CT系统的性能进行了优化和评估。测量了最大噪声等效计数率（NECR）的能量窗和NEMA 2001-NU2图像质量。利用F-18和I-124衰减源测量的因子校准图像的活度浓度（AC）精度进行了研究。能量窗为455-588 keV时，233mbq的最大NECR为9.67 kcps。I-124和F-18的图像质量相当，尽管I-124的背景可变性增加了。非均匀背景下I-124图像AC的平均低估值为17.9 +/- 2.9%，单散射模拟（SSS）减散射校正的平均低估值为14.7 +/- 2.9%。在224 MBq时，低估值为10.8 +/- 11.3%，与F-18的7.7 +/- 5.3%相当，但随着活性的降低而增加。利用SSS散射校正和衰减I-124源测量的校准因子，在优化的能量窗下获得了最佳的I-124 PET定量精度。I-124的定量精度与F-18相当，在高活度为224 MBq时，随着活度的降低而降低。对瞬发伽马光子的特定修正可以进一步提高定量精度。
Quantitative I-124 PET imaging is challenging as I-124 has a complex decay scheme. In this study the performance of a Philips Gemini dual GS PET/CT system was optimized and assessed for I-124.The energy window giving the maximum noise equivalent count rate (NECR) and NEMA 2001-NU2 image quality were measured. The activity concentration (AC) accuracy of images calibrated using factors from F-18 and I-124 decaying source measurements were investigated.The energy window 455-588 keV gave the maximum NECR of 9.67 kcps for 233 MBq. I-124 and F-18 image quality was comparable, although I-124 background variability was increased. The average underestimation in AC in I-124 images was 17.9 +/- 2.9% for nonuniform background and 14.7 +/- 2.9% for single scatter simulation (SSS) subtraction scatter correction. At 224 MBq the underestimation was 10.8 +/- 11.3%, which is comparable to 7.7 +/- 5.3% for F-18, but increased with decreasing activity.The best I-124 PET quantitative accuracy was achieved for the optimized energy window, using SSS scatter correction and calibration factors from decaying I-124 source measurements. The quantitative accuracy for I-124 was comparable to that for F-18 at high activities of 224 MBq but diminishing with decreasing activity. Specific corrections for prompt gamma-photons may further improve the quantitative accuracy.