摘要
目的:用西门子Volume Zoom CT机扫描CT模体与人体,探讨降低常规CT扫描剂量的可能性。方法:扫描CT模体,用120kV,mAs在260～180(每次递减20)。共5次。再对50例患者随机分为5组,用120kV,mAs在260～180(每次递减20),进行头颅CT扫描,扫描图像由3名高年资放射诊断医师进行盲审,结果与模体扫描结果进行对比分析。结果:当头颅CT扫描时,mAs由260降至220时,CT剂量指数由62.4降为52.8,降幅16%,两者差异有统计学意义,而图像质量无明显下降,但头颅CT扫描的mAs达到180时,图像噪声大,影响诊断,与模体扫描结果相关。结论:在降低mAs值得情况下,受检者所接受的X线剂量明显减少,在本CT机上,头颅扫描在200mAs以上的图像质量可以满足诊断要求。
Objective：To investigate the possibility of low dose CT scanning for Catphan 500 phantom and patients＇ heads by Volume Zoom CT scanner （Siemens,Germany）. Methods：Catphan 500 phantom was scanned for five times by Volume Zoom CT scanner with same tube voltage 120 KV and different tube currents from 180 mAs to 260 mAs with increment of 20 mAs. 50 patients undergoing head CT scan were enrolled into five groups with same scanning protocols as Catphan 500 phantom （same tube voltage 120 KV and different tube currents from 180 mAs to 260 mAs with increment of 20 mAs）. Images were analyzed by three experienced radiologists blindly. Resluts of Catphan 500 phantom and patients heads were compared. Results：Comparison of head CT and Catphan 500 phantom was without statistical difference. For head CT scan,reduction of tube currents from 260 mAs to 200 mAs without image quality imparement,led to statistical decreasing of CTDI from 62.4 to 52.8 with a percentage of 16. With tube current reducing to 180 ms,image noise was too big to make proper diagnosis. Conclusion：X-ray dosage exposure to patients decreases remarkably with tube current reduction. By Volume Zoom CT scanners,image quality of head with tube voltage 120 kV and tube current 200 mAs is sufficient for diagnosis.
出处
《中国医学装备》
2011年第7期36-38,共3页
China Medical Equipment
关键词
CT模体
CT剂量指数
影像质量
低剂量
Catphan 500 phantom
Computed tomography dose index
Image quality
Low dose
