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X 线的发现特别是 CT 的问世,使人为电离辐射日益增加,其中医疗照射是最大的辐射源,约占80%,CT 检查虽只占 X 线检查的5%,尤其多期螺旋 CT 扫描技术的应用(动脉期、静脉期、延迟期),病人的辐射量成倍增加,损害健康、诱发癌症的几率明显增高,特别是儿童对 X 线较成人敏感,更易受害,近年美国学者估计,美国约有500名15岁以下儿童者有可能直接由 CT 扫描引发癌症,以上数字令人堪忧。随着公共放射卫生和自身防护意识的不断提高,人们积极采取各种防护措施,低剂量 CT 扫描技术就是其中一种行之有效的方法。低剂量 CT 即在其他扫描参数不变的情况下,适当降低与 X 线剂量成线性关系的管电流,从而减少了患者的辐射量,又能保证图像的质量,满足诊断要求。
The discovery of X-ray, especially the advent of CT, has led to the increase of anthropogenic ionizing radiation. Among them, medical radiation is the largest radiation source, accounting for about 80%. Although CT scan accounts for only 5% of X-ray examinations, especially multislice CT scanning (Arterial phase, venous phase, delayed phase), the patient’s radiation doubled, damage to health, the risk of cancer was significantly increased, especially in children more sensitive to X-rays and more vulnerable to injury in recent years, the United States of America scholars estimate that the United States About 500 children under 15 years of age may be directly caused by CT scan of cancer, the above figures are worrying. With the continuous improvement of public radiological sanitation and self-protection awareness, people actively take various protective measures. Low-dose CT scanning technology is one of the effective methods. Low-dose CT is the same in other scanning parameters, the appropriate reduction in tube current and linear dose X-ray, thereby reducing the patient’s radiation, but also to ensure the quality of the image to meet the diagnostic requirements.