单双面阅读成像板影像质量与辐射剂量的对比研究

Dual-sided reading versus single-sided reading:comparison of image quality and radiation dose between the two computed radiography systems

目的对比研究单面阅读和双面阅读2种成像板(IP)成像质量与辐射剂量的关系。方法对单、双面阅读 IP,分别采用不同的辐射剂量对对比度.细节模体(CDRAD 2.0)进行曝光,记录每次曝光时模体表面的辐射剂量,模体的影像在图像诊断工作站显示器上由2名放射学专家进行视读,计算影像质量因子(IQF)并应用 Spearman 相关性检验和 Wilcoxon 秩和检验进行分析,比较2种IP 成像的图像质量与辐射剂量的差异。结果在管电流量分别为5.6、12.0、20.0、25.0和40.0 mAs时,单面阅读 IP 的 IQF 值分别是47.95、37.68、34.31、28.61、24.65;双面阅读 IP 的 IQF 值分别是38.83、29.81、29.65、25.16、21.43,2种阅读方式所得的 IQF 值差异有统计学意义(P<0.05)。结论辐射剂量相同时,双面阅读 IP 对于低对比度组织细节的检测能力优于单面阅读 IP;在获得相同影像信息时,应用双面阅读 IP 可比单面阅读 IP 降低约25%的辐射剂量。

Objective To assess and compare the difference in image quality and exposure dose between single-sided reading image plate （IP） and dual-sided reading IP. Methods A contrast-detail phantom CDRAD 2. 0 was exposed by single-sided and dual-sided reading IP with different mAs sets. The entrance surface doses were recorded for all images. Images were then presented to two radiologists on a high resolution monitor of diagnosis workstation. The image quality figure （IQF） was measured for each image. Statistical analysis was performed using Spearman＇s correlation test and Wilcoxon signed-rank test to compare the difference in image quality and exposure dose between single-sided IP and dual-sided reading IP. Results With different tube current dosage of 5.6, 12. 0, 20. 0, 25.0, and 40. 0 mAs, IQF values of single-sided reading IP were 47. 95, 37. 68, 34. 31, 28.61, and 24. 65, respectively, while those of dualsided reading IP were 38.83, 29. 81,29. 65,25. 16, and 21.43, respectively. The IQF difference between them showed statistical significance （ P 〈 0. 05）. Conclusion Image quality of dual-sided reading IP has been proved to be far superior to that of single-sided reading IP, in particular for low contrast detail. The image quality of single-sided reading IP is similar to that of dual-sided reading IP only at high dose levels. The clinical application of dual-sided reading IP will reduce the exposure dose by about 25% compared with single-sided reading IP.