【摘要】 目的 探讨胸部CT不同扫描定位下，结合无防护、180°及360°铅防护时辐射敏感器官的辐射剂量。方法 利用仿真人体模，在自动管电流技术下，分别采用前后位定位像、前后位+侧位定位像，变化腋前线、腋中线、腋后线三种侧位定位线，结合无防护、180°及360°铅防护，测量胸部CT时眼晶状体、甲状腺、乳腺、性腺的辐射剂量并进行统计学分析。结果 腋中线定位时，前后位+侧位定位像与前后位定位像相比，乳腺、晶状体、性腺的辐射剂量均降低，差异有统计学意义（P<0.05）；而甲状腺辐射剂量差异无统计学意义。定位像为前后位+侧位时，腋中线与腋前线比较，乳腺、甲状腺、性腺的辐射剂量均降低；腋中线与腋后线比较，晶状体的辐射剂量降低，差异有统计学意义（P<0.05）。前后位、腋中线定位时，甲状腺在常规剂量扫描180°铅防护时的辐射剂量小于低剂量扫描无防护时，差异有统计学意义（P<0.05）；性腺在常规剂量扫描360°铅防护时的辐射剂量小于180°铅防护及低剂量扫描无防护时，差异有统计学意义（P<0.05）；后两种方式扫描时，性腺的辐射剂量差异无统计学意义。结论 常规胸部CT扫描一般采用自动管电流、前后位定位像、腋中线定位，可选择前后位+侧位定位像，有利于降低乳腺、晶状体、性腺的辐射剂量。侧位定位线依然推荐腋中线。该条件下目前性腺仅有180°铅防护，建议采用效果更好的360°铅防护，可根据情况对甲状腺进行180°铅防护。更多还原

【Abstract】 Objective To explore the radiation dose to radiation-sensitive organs combined with unprotected,180° and 360° lead protection under different positioning of chest CT scanning.Methods With automatic tube current technology,the radiation dose of lens,thyroid,mammary gland and gonad during chest CT were measured using anterior-posterior positioning image,anterior-posterior + lateral positioning image in anthropomorphic phantom respectively.Three kinds of lateral positioning were adopted,including anterior axillary line,mid-axillary line,and posterior axillary line,combined with unprotected,180° and 360° lead protection.Results When using the mid-axillary line positioning,compared with the anteroposterior positioning images,the radiation dose of mammary gland,lens and gonad organs in anteroposterior + lateral positioning images were significantly lower(P<0.05),but there was no significant difference in the radiation dose of thyroid.When the positioning image was anteroposterior and lateral position,compared with the anterior axillary line,the radiation dose of mammary gland,thyroid and gonad in the mid-axillary line were decreased;compared with the posterior axillary line,the radiation dose of lens was decreased in the mid-axillary line(P<0.05).With the positioning image was anteroposterior and mid-axillary line position,the radiation dose of thyroid with 180° lead protection in routine dose scanning was less than that without protection in low dose scanning,and the difference was statistically significant(P<0.05).The radiation dose of gonads under 360° lead protection in routine dose scanning was less than 180° lead protection and no protection in low dose scanning,the difference was statistically significant(P<0.05);there was no significant difference in the radiation dose of gonad in the last two ways.Conclusion Conventional chest CT scanning generally adopts automatic tube current technology,anteroposterior positioning image and mid-axillary line positioning.Anteroposterior + lateral positioning images can be used to reduce the radiation dose of mammary gland,lens and gonad.Mid-axillary line is still recommended for lateral location.Under this condition,there is only 180° lead protection for gonad.It is recommended to adopt 360° lead protection with better effect,and 180° lead protection can be carried out for thyroid according to the situation.更多还原