PET/CT显像的图像融合精度测试研究

Research on Accuracy Measurement of the Fusion Images for the PET/CT Studies

目的:通过模拟和临床实际应用状态,测试3D全身显像方式PET/CT显像图像融合精度。方法:用测试模型及其配套的22Na固体点源,模拟人体宽度和厚度,采集点源PET/CT图像数据;然后将相同的点源置于检查床两测的床垫下,在检查床无负重和负重85kg时,分别采集PET/CT图像数据。重建图像后,在PET/CT融合图像的三个断层面分别寻找CT和PET点源图像的中心,测量二者中心偏差的mm数,即PET/CT图像融合精度。结果:PET和CT两种模态融合图像肉眼可见较明显的错位。模型点源PET/CT融合图像最大偏差为(4.25±0.26)mm、检查床无负重时为(3.96±0.26)mm,检查床负重85kg时为(5.36±0.26)mm。结论:本研究方法可以比较精确地测量PET/CT图像融合精度,并有效地指导PET/CT仪器的验收和故障检测等。

Objective： The aim of this study was to fred a way to measure the differences of the fusion images accurately on the 3D whole body PET/CT studies under the model simulating and patient clinical practise situation. Methods： The image fusion special model with 6 22Na solid point sources were imaged with Philips Gemini PET/CT for simulating the r-rays from the different positions in the patient body.Then the same point sources were put under the pad of the patient bed for acquiring the 3D whole body PET/CT data synchronously with and without patient on the bed. Image fusion differences were evaluated visually, and the centers of the CT and PET images were found on the PET/CT fusion images respectively, after reconstmtion and registering. Then the distances between the two centers of CT and PET images were measure accurately by millimeter （ram）. Resuits：Obvious image fusion differences were inspected on all of the point sources PET/CT images.The maximum differences were （4.25± 0.26） ram, （3.96 ± 0.26） mm and （5.36 ± 0.26） mm on the fusion images of the model, with and without patient on the bed,respectively. Conclusions： The fusion image differences maight be measured precisely with these methods, and it could also be used for the acceptance test and failure testing of PET/CT systems.