Aide Nicolas, Louis Marie-Hélène, Dutoit Soizic, Labiche Alexandre, Lemoisson Edwige, Briand Mélanie, Nataf Valérie, Poulain Laurent, Gauduchon Pascal, Talbot Jean-Noël, Montravers Françoise
Groupement Régional d'Etudes sur le cancer Unité Bioticla, EA 1772, Université de Caen and Centre François Baclesse, Caen, France.
Nucl Med Commun. 2007 Oct;28(10):813-22. doi: 10.1097/MNM.0b013e32822a0f37.
To evaluate the accuracy of semi-quantitative small-animal PET data, uncorrected for attenuation, and then of the same semi-quantitative data corrected by means of recovery coefficients (RCs) based on phantom studies.
A phantom containing six fillable spheres (diameter range: 4.4-14 mm) was filled with an 18F-FDG solution (spheres/background activity=10.1, 5.1 and 2.5). RCs, defined as measured activity/expected activity, were calculated. Nude rats harbouring tumours (n=50) were imaged after injection of 18F-FDG and sacrificed. The standardized uptake value (SUV) in tumours was determined with small-animal PET and compared to ex-vivo counting (ex-vivo SUV). Small-animal PET SUVs were corrected with RCs based on the greatest tumour diameter. Tumour proliferation was assessed with cyclin A immunostaining and correlated to the SUV.
RCs ranged from 0.33 for the smallest sphere to 0.72 for the largest. A sigmoidal correlation was found between RCs and sphere diameters (r(2)=0.99). Small-animal PET SUVs were well correlated with ex-vivo SUVs (y=0.48x-0.2; r(2)=0.71) and the use of RCs based on the greatest tumour diameter significantly improved regression (y=0.84x-0.81; r(2)=0.77), except for tumours with important necrosis. Similar results were obtained without sacrificing animals, by using PET images to estimate tumour dimensions. RC-based corrections improved correlation between small-animal PET SUVs and tumour proliferation (uncorrected data: Rho=0.79; corrected data: Rho=0.83).
Recovery correction significantly improves both accuracy of small-animal PET semi-quantitative data in rat studies and their correlation with tumour proliferation, except for largely necrotic tumours.
评估未进行衰减校正的半定量小动物PET数据的准确性，以及基于体模研究通过恢复系数（RC）校正后的相同半定量数据的准确性。
使用含有六个可填充球体（直径范围：4.4 - 14毫米）的体模，填充18F - FDG溶液（球体/背景活性 = 10.1、5.1和2.5）。计算定义为测量活性/预期活性的恢复系数。对50只荷瘤裸鼠注射18F - FDG后进行成像，然后处死。用小动物PET测定肿瘤中的标准化摄取值（SUV），并与离体计数（离体SUV）进行比较。基于最大肿瘤直径用恢复系数校正小动物PET的SUV。用细胞周期蛋白A免疫染色评估肿瘤增殖，并与SUV相关联。
恢复系数范围从最小球体的0.33到最大球体的0.72。发现恢复系数与球体直径之间呈S形相关性（r(2)=0.99）。小动物PET的SUV与离体SUV具有良好的相关性（y = 0.48x - 0.2；r(2)=0.71），并且基于最大肿瘤直径使用恢复系数显著改善了回归（y = 0.84x - 0.81；r(2)=0.77），除了具有严重坏死的肿瘤。通过使用PET图像估计肿瘤尺寸，在不处死动物的情况下获得了类似结果。基于恢复系数的校正改善了小动物PET的SUV与肿瘤增殖之间的相关性（未校正数据：Rho = 0.79；校正数据：Rho = 0.83）。
除了大部分坏死的肿瘤外，恢复校正显著提高了大鼠研究中小动物PET半定量数据的准确性及其与肿瘤增殖的相关性。
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