Geijer Håkan, Persliden Jan
Department of Radiology, Orebro University Hospital, SE-701 85 Orebro, Sweden.
Radiat Prot Dosimetry. 2005;114(1-3):240-5. doi: 10.1093/rpd/nch509.
The purpose of the study was to evaluate the image quality at different tube potential (kV) settings using anteroposterior lumbar spine radiography as a model. An Alderson phantom was used with a flat-panel detector. The tube potential varied between 48 and 125 kV while the tube charge (mAs) was adjusted to keep an effective dose of 0.11 mSv. Image quality was assessed with a visual grading analysis and with a CDRAD contrast-detail phantom together with a computer program. The VGA showed inferior image quality for the higher kV settings, > or =96 kVwith similar results for the contrast-detail phantom. When keeping the effective dose fixed, it seems beneficial to reduce kV to get the best image quality despite the fact that the mAs is not as high as with automatic exposure. However, this cannot be done with automatic exposure, which is set for a constant detector dose.
本研究的目的是以腰椎前后位X线摄影为模型，评估不同管电压（kV）设置下的图像质量。使用带有平板探测器的Alderson体模。管电压在48至125 kV之间变化，同时调整管电量（mAs）以保持有效剂量为0.11 mSv。通过视觉分级分析、使用CDRAD对比细节体模以及计算机程序来评估图像质量。视觉分级分析显示，管电压较高（≥96 kV）时图像质量较差，对比细节体模也得到了类似结果。当保持有效剂量固定时，尽管mAs不如自动曝光时高，但降低管电压似乎有利于获得最佳图像质量。然而，对于设定为恒定探测器剂量的自动曝光而言，无法做到这一点。
