卞冰阳,王静,周清晨,周华康,刘卓航,赵丽,李丹.颅脑CT检查患者辐射剂量最优化问题初探[J].中华放射医学与防护杂志,2019,39(3):224-229
颅脑CT检查患者辐射剂量最优化问题初探
Preliminary study on radiation dose optimization for patients with head CT
投稿时间:2018-07-16  
DOI:10.3760/cma.j.issn.0254-5098.2019.03.012
中文关键词:  蒙特卡罗  头围  敏感器官  辐射剂量  图像质量
英文关键词:Monte-carlo  Head circumference  mAs  Organ-Specific-Radiation doses  Image quality
基金项目:吉林省科学技术厅重点科技攻关项目(20150204061SF)
作者单位E-mail
卞冰阳 吉林大学第一医院放射线科, 长春 130021  
王静 吉林大学第一医院放射线科, 长春 130021  
周清晨 吉林大学第一医院放射线科, 长春 130021  
周华康 吉林大学第一医院放射线科, 长春 130021  
刘卓航 吉林大学第一医院放射线科, 长春 130021  
赵丽 吉林大学第一医院放射线科, 长春 130021  
李丹 吉林大学第一医院放射线科, 长春 130021 13604430730@126.com 
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中文摘要:
      目的 在蒙特-卡罗分析平台基础上,探讨根据头围调节管电流时间积(mAs)在颅脑CT成像的图像质量和敏感器官辐射剂量的应用价值。方法 前瞻性连续选取2017年9月至2018年6月期间吉林大学第一医院门诊或住院患者中的因为不同临床症状被建议行颅脑CT检查的儿童及青少年,共92名。不限定头围尺寸的情况下,采用随机数表法选取22例患者作为常规组,所测头围大小是48.1~59.2 cm。剩余70例患者归入低剂量组,低剂量组根据不同头围尺寸又分为3个亚组:A组,54.1~57.0 cm,22例;B组,51.1~54.0 cm,26例;C组,48.1~51.0 cm,22例。根据头围作为一个指标来指定mAs,因此,常规组和低剂量A、B、C组的管电流(mAs)分别为250、200、150、100 mAs。利用蒙特-卡罗分析平台记录敏感器官(脑实质、眼晶状体及唾液腺)辐射剂量值,并对主观和客观图像质量评分进行评价。采用单因素方差分析比较各组图像质量和辐射剂量的差异。结果 常规组和低剂量A、B、C组脑实质辐射剂量分别为(34.37±3.62)、(25.91±0.99)、(3.18±6.11)和(17.38±3.23)mSv,差异有统计学意义(F=54.51,P<0.05);眼晶状体辐射剂量分别为(41.54±1.04)、(33.03±0.35)、(26.18±2.72)和(20.88±4.45)mSv,差异有统计学意义(F=189.75,P<0.05);唾液腺辐射剂量分别为(35.04±4.94)、(25.92±0.99)、(22.93±6.54)和(14.96±2.67)mSv,差异有统计学意义(F=65.74,P<0.05)。常规组和低剂量A、B、C组主观图像质量评分分别为(4.97±0.13)、(4.77±0.49)、(4.67±0.49)和(3.98±0.61)分,差异有统计学意义(F=3.89,P<0.05),但常规组和A、B组之间差异无统计学意义(P>0.05)。常规组和低剂量A、B、C组灰质信噪比分别为(18.69±3.55)、(16.76±2.87)、(15.05±2.80)和(13.65±2.53),差异无统计学意义(P>0.05);白质信噪比分别为(17.46±3.72)、(15.54±2.81)、(13.71±2.43)和(11.77±2.18),差异亦无统计学意义(P>0.05)。结论 根据儿童和青少年头围尺寸调节mAs可使扫描方案更加个性化,在保证图像质量的前提下降低敏感器官辐射剂量。
英文摘要:
      Objective To investigate the effect of adjusting tube current time product (mAs) according to head circumference index on head CT image quality and organ-specific-dose level based on Monte Carlo analysis platform. Methods A total of 92 patients including children and adolescents with different clinical symptoms undergoing head CT scan were prospectively selected between September 2017 and June 2018 in the First Hospital of Jilin University. Without limiting the size of the head circumference, there were 22 patients were selected as conventional group by random number table, whose head circumference was 48.1-59.2 cm. Low dose group was divided into following three subgroups according to different head circumferences:A group 54.1-57.0 cm (n=22); B group 51.1-54.0 cm (n=26) and C group 48.1-51.0 cm (n=22). Tube current time product was 250 mAs for conventional group, 200 mAs for A group, 150 mAs for B group and 100 mAs for C group, respectively. The organ-specific-radiation doses (brain, eye lens and salivary gland) were recorded by Monte Carlo analysis platform and the subjective and objective image quality score was evaluated. Analyses of the differences between four groups were compared with image quality score as well as organ-specific-radiation dose by single factor variance. Results Radiation dose to brain was conventional group (34.37±3.62), A group (25.91±0.99), B group (23.18±6.11) and C group (17.38±3.23) mSv, respectively. The difference was of statistical significance in the four groups (F=54.51, P<0.05). Dose to eye lens was conventional group (41.54±1.04), A group (33.03±0.35), B group (26.18±2.72) and C group (20.88±4.45) mSv, with statistical significance in difference between the four groups (F=189.75, P<0.05). Dose to salivary gland was conventional group (35.04±4.94), A group (25.92±0.99), B group (22.93±6.54) and C (14.96±2.67) mSv, respectively, with statistical significance in difference between the four groups (F=65.74, P<0.05). Image quality scores were respectively conventional group (4.97±0.13), A group (4.77±0.49), B group (4.60±0.49) and C group (3.98±0.61), respectively, with statistical significance between them (F=3.89, P<0.05), but without statistical significance in difference between the four groups (P>0.05). The signal-to-noise ratios of gray matter in A, B and C groups were conventional group (18.69±3.55), A group (16.76±2.87), B group (15.05±2.80) and C group (13.65±2.53), respectively, without statistical significance in difference between the four groups (P>0.05); The signal-to-noise ratios of white matter in conventional group (17.46±3.72), A group (15.54±2.81), B group (13.71±2.43) and C group (11.77±2.18), respectively, without statistical significance in difference between the four groups (P>0.05). Conclusions Adjusting the tube current time product (mAs) according to head circumference index of children and adolescents can make scanning program more personalized and reduce organ-specific-radiation doses to sensitive organs without compromise of image quality.
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