Barkhausen J, Stöblen F, Müller R D, Streubühr U, Ewen K
Zentralinstitut für Röntgendiagnostik, Universitätsklinikums Essen.
Aktuelle Radiol. 1998 Sep;8(5):220-4.
The aim of the study was to optimize the scan parameters for spiral-CT of the thorax.
Using a Somatom AR-SP (Siemens AG, Erlangen) CT-unit, four different scanning protocols (collimation/table feed) were compared: A (5/10), B (10/10), C (10/15), D (10/20). High contrast resolution in the xy-plane and in the z-direction were investigated with special phantoms. Noise levels were measured using a water phantom, the radiation exposure of lung parenchyma was investigated using an Alderson-Rande-Phantom. An anthropoid chest phantom was scanned to compare the image quality of the four protocols.
Protocol A showed the best resolution in the z-direction; the resolution in the xy-plane was equal for all protocols. Image noise in the center of the water phantom was 58 HU for protocol A and 40 HU for the other three. The following equivalent organ dose were measured for lung parenchyma: A 14 mSv, B 29 mSv, C 20 mSv, D 14 mSv.
Scanning protocols with small collimation and a pitch of 2 are characterised by low radiation exposure and excellent resolution in the z-direction. These parameters seem to be most suitable for lung scanning.
本研究的目的是优化胸部螺旋CT的扫描参数。
使用一台Somatom AR-SP（西门子公司，埃尔朗根）CT设备，比较四种不同的扫描方案（准直/床速）：A（5/10）、B（10/10）、C（10/15）、D（10/20）。使用特殊模体研究xy平面和z方向的高对比度分辨率。使用水模体测量噪声水平，使用Alderson-Rande模体研究肺实质的辐射剂量。扫描一个仿真人体胸部模体以比较这四种方案的图像质量。
方案A在z方向显示出最佳分辨率；所有方案在xy平面的分辨率相同。水模体中心的图像噪声，方案A为58 HU，其他三种方案为40 HU。测量得到的肺实质等效器官剂量如下：A为14 mSv，B为29 mSv，C为20 mSv，D为14 mSv。
小准直和螺距为2的扫描方案的特点是辐射剂量低且在z方向分辨率优异。这些参数似乎最适合肺部扫描。
