摘要
目的通过分析计算机 X 线摄影(CR)系统的采样频率和栅密度频率,提出尽可能有效避免滤线栅伪影出现的抑制方法。方法实际测试不同栅密度的滤线栅与不同规格的成像板(IP)匹配使用,得到不同效果的图像;模拟2种信号频率(即2种栅密度的滤线栅),采用3种采样频率[6、8、10图像空间分辨率(pixels/mm)],得到不同的模拟图像效果。结果通过对比分析模拟图和实际图像,发现在采样频率正好等于信号频率的2倍时,可以得到正确的信号频率,图像清晰,无混淆现象。栅密度<4 LP/mm 时,可较好地与14 in×14 in、10 in×12 in(1 in=2.54 cm)IP 匹配使用。结论 CR 系统与普通 IP 匹配使用合适的采样频率和栅密度频率,可以有效避免滤线栅伪影出现。
Objective To analyze sampling frequency and grid density frequency on the computed radiography （CR） system and to develop an effective method to suppress or eliminate grid artifacts. Methods To test grids with different grid-density in combination with IP boards of different specifications. Radiographic images with various qualities were obtained by simulating two kinds of signaling frequencies （namely two kind of grids with different grid densities）, and utilizing three kinds of sampling frequencies （6, 8, 10 pixels/mm）. A variety of different simulation images were obtained. Results By comparing simulation images with actual images, it was discovered that correct signaling frequency could be achieved if the sampling frequency were equal to twice the signaling frequency. The obtained image was clear and free of grid artifact. A grid density of 〈4 LP/mm was most suitable for IP boards of 14 in × 14 in, 10 in × 12 in, in size. Conclusion Appropriate combination of the CR System and IP boards with matching sampling frequency and grid-density frequency can effectively eliminate or reduce grid artifacts.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2007年第11期1249-1251,共3页
Chinese Journal of Radiology
