分析不同参数对胸部增强CT扫描辐射剂量的影响

An analysis on impact of different parameters for radiation dosage of enhanced CT of chest

目的:分析胸部增强X射线计算机断层成像(CT)检查的辐射剂量数据,探讨胸部增强CT扫描的诊断剂量及其影响因素。方法:回顾性分析对比在4台CT设备上扫描的297例患者扫描数据,按设备型号分为设备A组、设备B组、设备C组和设备D组,比较CT设备间扫描序列的差别,统计分析CT容积剂量指数(CTDI_(vol))、剂量长度乘积(DLP)和有效剂量(ED)。结果:4组设备对所有病例扫描的CTDIvol值分别为(12.18±4.13)mGy、(8.86±3.18)mGy、(10.70±5.18)mGy和13.59 mGy,之间比较差异有统计学意义(F=38.58,P<0.05);4组病例的DLP值分别为(433.54±145.18)mGy·cm、(311.62±112.75)mGy·cm、(368.04±181.22)mGy·cm和(475.75±34.25)mGy·cm,之间比较差异有统计学意义(F=36.33,P<0.05);4组病例的ED值分别为(6.07±2.03)、(4.36±1.58)、(5.15±2.54)和(6.66±0.48)m Sv,之间比较差异有统计学意义(F=36.32,P<0.05)。辐射剂量两两比较均有差异。结论:胸部增强CT扫描患者的受照剂量与CT机型号及采集参数相关,自动管电流模式下患者的有效剂量低于固定管电流;角度射线管电流调制技术会有效降低患者有效剂量,临床中可以通过优化采集条件降低患者的受照剂量。

Objective： To explore the diagnostic dosage of enhanced computed tomography（CT） of chest and its influence factor through analyzed the data of radiation dosage of enhanced CT of chest. Methods： The scanning data of 297 patients who were implemented scan on 4 different CT devices were compared by using retrospective analysis. And they were divided into A, B, C and D group as different device. The differences of scan sequence among different devices were compared, and volume computed tomography dose index（CTDIvol）, dose length product（DLP） and effective dose（ED） were recorded and analyzed. Results： The CTDIvols of 4 groups were（12.18±4.13）,（8.86±3.18）,（10.70±5.18） and 13.59 m Gy, respectively, and the differences among them were significant（F=38.58, P〈0.05）. And the DLPs of the 4 groups were（433.54±145.18）,（311.62±112.75）,（368.04±181.22） and（475.75±34.25）m Gy·cm, and the differences among these groups were significant（F=36.33, P〈0.05）. Besides, the EDs of the 4 groups were（6.07±2.03）,（4.36±1.58）,（5.15±2.54） and（6.66±0.48） m Sv, and the differences among these groups also were significant（F=36.32, P〈0.05）. And the comparison between any two means of radiation dosage were significant. Conclusion： The exposure dose of patients who received enhanced CT of chest was correlative with the type of CT device and acquisition parameters. And the effective dosage of patients under automatic tube current module was lower than that of fixed tube current module. And the modulation technique of current of ray tube as angle can efficiently reduce the effective dose. In clinical practice, patients＇ radiation dosage can be reduced by optimizing the scanning parameters.