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目的探讨鼻骨DR不同曝光模式辐射剂量和图像质量的关系。方法用DR出厂设定的鼻骨曝光量对PMMA模拟鼻骨厚度1.25cm和对比度细节体模(CDRAD2.0)组合行自动曝光控制(AEC)摄影,选定合理的曝光量为65kV、1mAs。对不同曝光量下mAs、ESD、DAP和IQF值的差异和不同曝光模式图像的影像诊断效能行统计学分析。结果①固定管电压65kV,随着mAs提高ESD、DAP增加,其间比较有显著性差异(F=1106、1416,P<0.05)。IQF值变化不明显,差异比较无统计学意义。②固定管电流1 mAs,55 kV时,曝光量不足。65kV～85kV的ESD、DAP之间差异比较有统计学意义,IQF值差异比较无统计学意义。不同曝光模式图像诊断鼻骨骨折的ROC曲线下面积之间比较无显著性差异。结论①在保证图像质量的前提下,65 kV、0.5 mAs手动曝光较65 kV自动曝光的辐射剂量更低,可作为成人鼻骨DR手动曝光模式的适宜曝光量。②AEC初始曝光量的设定水平有必要校验,其有助于手动模式适宜曝光量范围的确定。
Objective To investigate the relationship between radiation dose and image quality of nasal bone DR in different exposure modes. Methods Ammoencephalitis (PMMA) simulated nasal bone thickness 1.25cm and contrast detail phantom (CDRAD2.0) were combined with exposure exposure (AEC) photography with DR factory default exposure. The reasonable exposures were selected as 65kV and 1mAs. The statistical analysis of the difference of mAs, ESD, DAP and IQF values and the diagnostic performance of different exposure images under different exposures were performed. Results ① With a fixed tube voltage of 65 kV, DAP increased with increasing mAs, with a significant difference (F = 1106, 1416, P <0.05). IQF values did not change significantly, the difference was not statistically significant. ② Fixed tube current 1 mAs, 55 kV, the exposure is insufficient. The differences of ESD and DAP between 65kV and 85kV were statistically significant, and there was no significant difference between IQF values. There was no significant difference between the areas under ROC curve of nasal fracture in different exposure mode images. Conclusion ① Under the premise of ensuring the image quality, the exposure dose of 65 kV, 0.5 mAs manual exposure is lower than that of 65 kV automatic exposure, which can be used as appropriate exposure for adult nasal bone DR manual exposure mode. ② AEC initial exposure level setting is necessary to check, which helps to determine the appropriate manual mode exposure range.