器官剂量调制技术降低肺结核病人胸部CT平扫辐射剂量探讨

Influence of organ dose modulation on thyroid radiation dose of tuberculosis patients

目的探讨使用器官剂量调制(ODM)技术对肺结核病人在胸部CT扫描中辐射剂量降低方法。方法选择肺结核病人30例,其中男性18例,女性12例;年龄28~67岁,平均年龄45岁;体质量指数(63.7±11.6)kg/m^2。同一例病人第一次行胸部CT平扫扫描为对照组,跟踪病例复诊CT扫描为试验组。对照组行常规胸部CT扫描,试验组行胸部CT扫描时打开ODM,对病人甲状腺进行防护。两组均采用Z轴自动管电流调节技术,噪声指数12,计算有效剂量(ED)。两组图像由两名医生进行主观评价,并对评价作一致性检验。结果两组辐射剂量比较,试验组较对照组CT剂量指数(CTDIvol)减低9.03%,ED减低9.86%;两组比较,差异有统计学意义(t=2.073 5、1.795 7,P<0.05)。试验组图像质量评分为(4.13±0.73)分,对照组为(4.10±0.75)分;两组评分比较,差异无统计学意义(P=0.86>0.05)。两名医生诊断一致性检验评价Kappa=0.869(0.759~0.979)。图像质量满足临床诊断。结论 ODM技术的合理使用在不影响诊断的前提下,有效降低胸部CT扫描中的辐射剂量。

Objective To study the effect of organ dose modulation（ODM） on decreasing the thyroid radiation dose of tuberculosis patients in chest CT scanning. Methods A total of 30 tuberculosis patients were enrolled, which included 18 males and 12 females, aged 28-67 years old with mean age of 45 years old and body weight index of（63.7 ± 11.6） kg/m～2. The patients initially followed up with plain chest CT scanning were set as control group, and patients followed up with the additional CT scanning were set as experimental group. The thyroid gland was protected in 2 groups, the control group was performed by routine chest CT scan and experimental group was performed by CT scanning with ODM triggered. The automatic tube current modulation technique in Z axis was used with noise index of 12, and effective dose（ED） was calculated. The CT images were evaluated by two professional doctors, and tested for consistency. Results Compared with control group, the volume CT dose index（CTDIvol） in experimental group was decreased to 9.03 %（t = 2.073 5, P〈0.05）, and ED decreased to 9.86 %（t = 1.795 7,P〈0.05）, the differences were statistical significance between 2 groups. The image quality score of experimental group was（4.13 ± 0.73） and that of control group was（4.10 ± 0.75）, there was no significant difference between 2 groups（P = 0.86 0.05）.The diagnostic consistency test evaluation of Kappa = 0.869（0.759-0.979）. The image quality was met the clinical diagnostic requirements. Conclusion It is demonstrated that ODM is effective to reduce the radiation dose of chest CT scanning without adverse influence on diagnosis.