| Objective The introduction of combined pet/ct systems has a number ofadvantages, including semi-quantion which is the indices of physiologicalfunction. The commonly applied semi-quantitative paramtres are thestandardised uptake value(SUV)and target to background(T/B).SUV is avaluable tool for determination the rate of glucose metabolism in18F-PET.It iswidely used in cancer diagonise and differential diagnosise, as well asprognostic evaluations.SUV is affected by many factors,and so manyparameters were researced, but the impact of acqusition time on thesemi-quantitative caculation was fewer and so far controversial.This paper waslooking for a more stable and accurate semi-quantitative indicator by comparingthe changing of suv and t/b with difffferent time.Method The sthdy collected53cases who underwent pet/ct(Germancompany simens bio sensation16.0scanner) from June2013to December2013in the first affiliated hospital of Guangxi Medical universit. this contextchoosed bilateral parotid gland and nasopharynx prevertebral muscles as thetarget,and all the lesions were indentified in the corresponding3min/bed petimages. All the lesions from could be detcted in the two kinds of acqusition time,30minutes and60minutes.Result30min (1.3566±0.05814) parotid mean SUVmax was less than60min (1.6594±0.4398) parotid SUVmax, the difference was statisticallysignificant;30min (1.8783±2.30379) vertebral anterior nasopharynx meanSUVmax was less than60min (2.6774±3.01286) nasopharynx anterior muscleSUVmax, the difference was statistically significant;30min (1.0234±0.4715) T/B was less than the average number of60min (1.8643±0.38008),but thedifference was statistically insignificant. Pearson correlation coefficientRsuvmax=6.371,Rt/b=0.614p=0.006, it can be considered a positive linearcorrelation between the aquisition time of30min and60min about thesemi-quantition.Conclusion acquisition time have significant effect on thesemi-quantitative indicators, and SUVmax greater than the T/B, T/B is morestable than the SUVmax,the image quality of60min after the start of datacollected is superior to30min after the start of the data, The former improvesthe signal to noise ratio of the image,in additional closer to reflect the true sizeof the lesion. As well as shorten the acquisition time witheout erducing theacquisition qulity. |
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