Chotas H G, Van Metter R L, Johnson G A, Ravin C E
Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Radiology. 1991 Sep;180(3):853-9. doi: 10.1148/radiology.180.3.1871306.
The ability of a commercially available scanning equalization system for chest radiography to render small object contrast in the lung-, mediastinum-, and subdiaphragm-equivalent regions of an acrylic chest phantom was quantitatively evaluated. Images from nine chest phantoms that represented a wide range of patient sizes and dynamic ranges of x-ray transmittance were analyzed. Subject contrast was measured with a photostimulable phosphor detector, and images were acquired in both equalized and nonequalized (conventional) imaging modes. Available subject contrast in the lung-equivalent region was 8%-15% lower in the equalized images compared with the nonequalized images in all phantoms (patient types); contrast in the mediastinum-, retro-cardiac-, and subdiaphragm-equivalent regions was 11%-63% higher in the equalized images, with the degree of improvement increasing as patient size and dynamic range increased. Images of each phantom were also acquired with the screen-film systems currently in use at the authors' institution, permitting an assessment of the relative performance (in terms of radiographic contrast) of these imagers with and without use of equalization.
对一种市售的胸部X线摄影扫描均衡系统在丙烯酸胸部体模的肺、纵隔和膈下等效区域呈现小物体对比度的能力进行了定量评估。分析了来自九个胸部体模的图像，这些体模代表了广泛的患者体型和X线透射率动态范围。使用光激励荧光探测器测量受试者对比度，并在均衡成像模式和非均衡（传统）成像模式下采集图像。在所有体模（患者类型）中，与非均衡图像相比，均衡图像中肺等效区域的可用受试者对比度降低了8%-15%；在均衡图像中，纵隔、心后和膈下等效区域的对比度提高了11%-63%，随着患者体型和动态范围的增加，改善程度也增加。还使用作者所在机构目前使用的屏-片系统采集了每个体模的图像，从而可以评估这些成像设备在使用和不使用均衡时的相对性能（在射线照相对比度方面）。
