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目的测定婴幼儿与成年人颅脑CT检查接受辐射剂量的状况,对此进行对比分析并做出结论。方法随机选择颅脑CT检查婴幼儿和成年人各61例,测量CT扫描患者体重。CT扫描均在120 kVp条件下完成,其中儿童曝光量为130mAs,成人的曝光量为130 mAs(在小脑幕上结构)和150 mAs(在幕下结构)。从CT图像上读出扫描层厚和扫描层数。为精确估算辐射剂量,将患者头部模拟为标准水模,选择典型的第三脑室上部横断图像测量矢状径、冠状径,用以模拟水模等值半径、计算头部平均层面剂量、传递给患者的X线能量以及相应有效剂量。结果婴幼儿头部的模拟水模等值半径随其体重呈增长趋势,对于2 kg的新生儿和11 kg的婴幼儿模拟水模等值半径分别为38.70 mm和75.33 mm。而成年人模拟水模等值半径平均为87.63 mm,体重与其相关性较小。婴幼儿颅顶颅底的平均层面剂量均是22.11 mGy,而成人颅顶平均层面剂量为16.21 mGy,颅底平均层面剂量为18.71 mGy。传递给婴儿的能量大小与病人体重之间的关系(r2=0.527)远比成年人(r2=0.302)明显。病人有效剂量与病人体重间无明显的关联(儿童r2=0.683,成人r2=0.302)。婴幼儿接受的能量(19.11 mJ)近似于成人所接受值(40.25 mJ)的一半。婴幼儿接受的有效剂量为3.26 mSv,是成年人所受有效剂量(0.45 mSv)的7倍。结论婴幼儿头部CT检查所受辐射剂量表明婴幼儿CT检查的沉重代价以及降低其剂量的必要性,本研究成果与Huda的研究结论相比较表明了降低婴幼儿辐射剂量的可行性。
Objective To determine the radiation dose received by craniocerebral CT examination in infants and young adults, and to make a comparative analysis and conclusion. Methods Totally 61 cases of infants and young adults were randomly selected from brain CT examination, and the body weight of CT scan was measured. CT scans were performed at 120 kVp with 130 mAs for children and 130 mAs for adults (in the supratentorial sac) and 150 mAs (in the infratentorial structures). The scan layer thickness and the number of scanning layers are read out from the CT image. In order to accurately estimate the radiation dose, the patient’s head is simulated as a standard water model, and the sagittal and coronal diameters of typical third ventricle transection images are selected to simulate the equivalent radius of the water model. The average dose of the head is calculated and transmitted Give the patient the X-ray energy and the corresponding effective dose. Results The equivalent radius of simulated water model in infants and toddlers tended to increase with body weight. The equivalent radius of simulation water model for newborns with 2 kg and infants with 11 kg was 38.70 mm and 75.33 mm, respectively. However, the average equivalent radius of simulated water model for adults is 87.63 mm on average, and the correlation between body weight and body weight is small. The mean level of skull base in infants and children was 22.11 mGy, while the mean level of adult skull base was 16.21 mGy. The average skull base level was 18.71 mGy. The relationship between the amount of energy delivered to a baby and the patient’s body weight (r2 = 0.527) is significantly greater than in adults (r2 = 0.302). There was no significant correlation between patient effective dose and patient weight (r2 = 0.683 for children and r2 = 0.302 for adults). The energy an infant receives (19.11 mJ) is approximately half the adult acceptance value (40.25 mJ). Infants and young children receive an effective dose of 3.26 mSv, which is seven times the effective dose (0.45 mSv) in adults. Conclusion The radiation dose of head CT examination in infants shows the heavy price of CT examination in infants and young children and the necessity of reducing its dosage. The results of this study compared with Huda ’s conclusion indicate the feasibility of reducing infant radiation dose.