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目的:探求不同滤波函数和截止频率对PET 重建图像的影响,以获得适合临床各项检查的最佳滤波条件。材料和方法:PET 质控模型。用PET 对其进行常规采集,以不同滤波条件重建图像后进行比较。结果:冷区图像重建,当fc 相同时Hann 和Ham m 的比值优于其它滤波函数。比值优劣次序为Ham m 、Hann、Parzen 、Butterworth 和Butterworth2 。重建图像的噪声高低排序为:Ham m 、Hann 、Buterworth、Parzen 和Butterworth2 。相同滤波函数随fc 增高,高频噪声增加。热区图像的FWHM 随fc 减小而增大。排列为:Ham m 、Butterworth 、Hann 、Parzen 和Butterworth2 。周边圆柱的FWHM 比中心圆柱的大,差值最小的是Butterworth 。结论:(1) 重建脑断层图像,建议采用Ham m 或Hann ,fc = 0-3～0-4 或Butterworth ,fc= 0-4 ～0-5 。(2) 热区图像可适当提高fc,以提高分辨力。(3) 计算热区实际大小时可用FWHM估算,对直径1cm 的热区,Ham m 和Hann 在fc= 0-3 时,Butterworth 在fc= 0-2 时FWHM 接近实际大小。
Objective: To explore the effect of different filter functions and cutoff frequencies on PET reconstruction images to obtain the best filtering conditions suitable for clinical examination. Materials and Methods: PET quality control model. It was routinely collected with PET and reconstructed with different filtering conditions for comparison. Results: In the cold region image reconstruction, the ratio of Hann to Hamm is better than other filter functions when fc is the same. The odds order is Ham m, Hann, Parzen, Butterworth, and Butter -worth2. Reconstructed images are sorted by Hamm, Hann, Buterworth, Parzen, and Butterworth2. The same filter function increases with fc, high-frequency noise increases. The FWHM of the hot zone image increases as fc decreases. Arranged as: Ham m, Butterworth, Hann, Parzen and Butterworth2. The surrounding columns have a larger FWHM than the center cylinder, with the smallest difference being Butterworth. Conclusions: (1) To reconstruct the brain tomographic image, we suggest Hamm or Hann, fc = 0-3 ~ 0-4 or Butterworth, fc = 0-4 ~ 0-5. (2) hot zone image can be increased fc, to improve resolution. (3) FWHM can be used to calculate the actual size of the hot zone. For a hot zone of 1cm in diameter, Hamm and Hann at fc = 0-3, Butterworth approaches the actual size at fc = 0-2.