CAJ | 학술논문

目的评价在进行头颈部CT扫描血管成像时,Z轴自动管电流调制技术(ATCM)对减少甲状腺的辐射剂量的作用及对图像噪声的影响.方法回顾性地分析140例头颈部CT增强血管成像的病例,其中用固定管电流技术和Z轴自动管电流调节技术各70例,观察其成像质量,记录其客观噪声水平(由CT图像衰减值的标准差进行评估),并比较其单次扫描的加权CT剂量指数CTDIw,管电流mA及剂量长度乘积DLP.结果在扫描范围、扫描参数(管电压、螺距、准直器厚度等)、造影剂注射速率和注射部位完全相同的情况下,固定管电流技术和Z轴自动管电流调节技术的图像质量相同,甲状腺图像噪声分别为10.14和13.64 HU.单次扫描的加权CT剂量指数CTDIw(mGy)分别为(43.22±1.42)和(35.99±1.31)mGy.剂量长度乘积分别为(1514.45±5.56)和(1121.39±5.51)mGy·cm,剂量长度乘积降低约25.95%.结论 Z轴自动管电流调节技术能有效降低总曝光量和累计剂量长度乘积,可以有效地降低患者的辐射剂量,特别是像甲状腺和眼晶体等射线敏感组织器官的辐射剂量降低,减少其辐射危害,但是图像噪声略有增加.
목적 평개재진행두경부CT소묘혈관성상시,Z축자동관전류조제기술(ATCM)대감소갑상선적복사제량적작용급대도상조성적영향.방법 회고성지분석140례두경부CT증강혈관성상적병례,기중용고정관전류기술화Z축자동관전류조절기술각70례,관찰기성상질량,기록기객관조성수평(유CT도상쇠감치적표준차진행평고),병비교기단차소묘적가권CT제량지수CTDIw,관전류mA급제량장도승적DLP.결과 재소묘범위、소묘삼수(관전압、라거、준직기후도등)、조영제주사속솔화주사부위완전상동적정황하,고정관전류기술화Z축자동관전류조절기술적도상질량상동,갑상선도상조성분별위10.14화13.64 HU.단차소묘적가권CT제량지수CTDIw(mGy)분별위(43.22±1.42)화(35.99±1.31)mGy.제량장도승적분별위(1514.45±5.56)화(1121.39±5.51)mGy·cm,제량장도승적강저약25.95%.결론 Z축자동관전류조절기술능유효강저총폭광량화루계제량장도승적,가이유효지강저환자적복사제량,특별시상갑상선화안정체등사선민감조직기관적복사제량강저,감소기복사위해,단시도상조성략유증가.
Objective To assess the effectiveness of Z-axis automatic tube current modulation ( ATCM) technique with respect to dose reduction and image noise in the thyroid regional tissues during neck computed tomography angiography (CTA). Methods A total of 140 patients underwent neck CTA with 64-slice spiral CT, and were randomized into fixed-tube current group and ATCM group. Objective noise, CTDIw, DLP and mA of each group were recorded. Results The image qualities of all the patients were diagnostically acceptable, though the objective noise of neck in the ATCM group was higher than that in the group of fixed-tube current (P＜ 0.05 ). The radiation doses in the ATCM group [ CTDIw (35.99±1.31 ) mGy, DLP (11 121.39 ±5.51) mGy·cm] were significantly inferior to those in the group of fixed tube current [ CTDIw (43.22±1.42) mGy, DLP (1514.45±5.56) mGy·cm]. Conclusions Compared with fixedtube current technique, ATCM technique could significantly reduce the radiation dose in neck CT with diagnostic acceptability of the image quality.