Ultra-low-dose computed tomography system with a flat panel detector: assessment of radiation dose reduction and spatial and low contrast resolution
Ultra-low-dose computed tomography system with a flat panel detector: assessment of radiation dose reduction and spatial and low contrast resolution
复制标题
带有平板探测器的超低剂量计算机断层扫描系统：评估辐射剂量减少以及空间和低对比度分辨率
作者：
Y. Nagatani;N. Nitta;Masashi Takahashi;N. Tezuka;Y. Nakano;M. Ikeda;Yuki Kirino;Keiji Hashimoto;H. Otani;Yoko Murakami;K. Murata
目的介绍一种装有平板探测器的锥形束计算机断层扫描系统（FPD-CT系统）的原型，并测量其辐射剂量、空间分辨率和低对比度分辨率。材料与方法将患者旋转为坐位，用平板探测器从固定x射线管中获取锥束数据。在丙烯酸体中定量评估吸收剂量、空间分辨率和低对比度分辨率以及CT衰减值的变化。正常血管的可见性在临床图像的7名患者进行定性分析，由5名委员会认证的放射科医生。将这些定量和定性数据与FPD-CT系统和多检测器行CT （MDCT）进行比较。结果FPD-CT获得的肺中央野图像具有最低的低对比度灵敏度和中等的空间分辨率。FPD-CT系统中的吸收剂量下降到MDCT系统中剂量的约2.5%。结论考虑到肺野中心区正常血管和支气管的交叉结构，FPD-CT对肺野中心区肺部异常的检测和频繁随访具有较好的空间分辨率。
PurposeThe aim of this study was to introduce a prototype cone-beam computed tomography system equipped with a flat panel detector (FPD-CT system) and measure its radiation dose and spatial and lowcontrast resolution.Materials and methodsA patient was rotated in a sitting position, and cone beam data were acquired with the flat panel detector from a fixed X-ray tube. Absorbed dose, spatial and low-contrast resolution, and variation in the CT attenuation value were assessed quantitatively in the acrylic phantom. The visibility of normal blood vessels in clinical images of seven patients was analyzed qualitatively by five board-certified radiologists. These quantitative and qualitative data were compared between the FPD-CT system and multidetector row CT (MDCT).ResultsMinimal low-contrast sensitivity and a moderate spatial resolution were demonstrated in images of central lung fields acquired by FPD-CT. The absorbed dose in the FPD-CT system decreased to approximately 2.5% of the dose in the MDCT system.ConclusionConsidering crossover structures in normal blood vessels and bronchi in the central areas of lung fields, this result implies that fairly acceptable spatial resolution can be realized with FPD-CT for detection and frequent follow-up of pulmonary abnormalities in the central lung fields.