摘要
目的用Jaszczak模型及心肌模型检测及评价SPECT和正电子符合探测显像衰减校正在肿瘤和心肌显像中的应用效果。方法用Jaszczak模型充满^18F-脱氧葡萄糖（FDG）溶液，充分混匀，分别在Vertex Plus机型和Hawkeye机型上做模型图像的采集并进行图像重建。结果Vertex Plus衰减校正后的图像质量明显改善，周边和深部的计数之差减少，深部的计数得到补偿。校正后的图像可以发现直径为9mm的“冷”区，而7mm的“冷”区则难以辨认，“热”区可以分辨到6mm。Hawkeye衰减校正后的圆形“冷”区有较大的改善，校正前对直径在12mm以下的“冷”区都无法显示，中央的“冷”区几乎与本底相似，难以分辨，周边的放射性与中央部分的放射性计数差距较大。校正后的图像可以发现5个“冷”区，而7mm的“冷”区则难以辨认。结论衰减校正的模型实验显示用^137Cs作为穿透射线方法的校正效果优于Hawkeye X线球管，不仅明显改变图像质量，而且可以明显改善空间分辨率，在“冷”区可以显示到直径9mm，而“热”区则可以显示到6mm。
Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assessment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography images. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems （SPECT/PET） and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of ^18F-fluorodeoxyglucose （FDG） and was scanned with two hybrid SPECT/coincidence PET systems respectively （Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company）. The PET images were acquired and reconstructed. Results The ＂cold＂ lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify ＂hot＂ lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the ＂hot＂ lesion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obviously ; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round ＂ cold＂ lesions could be recognized, the diameter： 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was almost as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 ＂cold＂ lesions could be found, 9, 12, 14, 18 and 20 mm, but 7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm ＂ hot＂ lesions could be found, and by the surrounding, there was an arc shape ＂ hot＂ lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm ＂hot＂ lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of attenuation with phantom showed that ^137 Cs was better than CT in both image quality and spatial resolution.
出处
《中华核医学杂志》
CAS
CSCD
北大核心
2009年第3期201-204,共4页
Chinese Journal of Nuclear Medicine
