新型一体化医用CT机辐射防护装置的研制及其评价

Development and evaluation of a novel integrated radiation protection device for CT

目的探讨新型一体化CT辐射防护装置辐射防护效果及其对图像质量的影响。方法依据辐射防护原理及CT机型设计研发新型一体化CT辐射防护装置,在CT机正常运行条件下,测量辐射防护装置使用前后CT机周围环境7个监测点的辐射剂量率并计算有效防护率。在使用防护装置前后分别对水当量模体进行CT扫描,测量水当量模体CT值和信噪比,并采用3分制对图像质量进行主观评估。采用配对t检验比较防护装置使用前后CT机周围环境辐射剂量率、平均CT值及信噪比的差异,采用Mann-Whitney U检验比较防护前后水当量模体CT图像质量主观评分的差异。结果7个监测点在新型CT辐射防护装置使用后的辐射剂量率均较使用前明显下降,差异均有统计学意义(P<0.05),且有效防护率均在50%以上;辐射防护装置使用前后水当量模体范围内平均CT值、信噪比及主观评分差异均无统计学意义(P>0.05)。结论新型一体化CT辐射防护装置能够明显降低CT机运行时周围环境辐射剂量率且对图像质量无影响。

Objective To explore the radiation protection effect of a novel integrated radiation protection device for computed tomography and evaluate its influence on image quality.Methods According to the radiation protection principle and CT model,a novel integrated CT radiation protection device was designed and developed.Under the normal operation condition of CT scanner,the radiation dose rate of 7 monitoring points around CT scanner before and after the use of radiation protection device was measured and the effective protection rate was calculated.Before and after using the protective device,the water equivalent phantom was scanned with CT respectively,CT value and signal-to-noise ratio were measured and calculated,and the image quality was evaluated subjectively with the 3-point system.The paired t-test was used to compare the difference of radiation dose rate,average CT value and signal-to-noise ratio of CT surrounding environment before and after using the protective device,and the Mann Whitney U-test was used to compare the difference of subjective scores of CT image quality of water model before and after using the protective device.Results The radiation dose rates of the 7 monitoring points after the use of the novel CT radiation protection device was significantly lower than those before radiation protection device was used,the difference was statistically significant(P<0.05),and the effective protection rate was more than 50%;the average CT value,signal-to-noise ratio and subjective score in the range of water equivalent phantom before and after the use of the radiation protection device were not statistically significant(P>0.05).Conclusions The novel integrated CT radiation protection device can significantly reduce the radiation dose rate of the surrounding environment when the CT machine is running and has no effect on the image quality.