数字化X线摄影系统拼接图像的可靠性探讨

目的：探讨数字化X线摄影系统拼接图像的可靠性。方法：对照组：X线球管中心线对模型1标尺的中点标记进行垂直摄影，照射野包含标尺的两侧标记，摄影距离120cm，物一台距离3．5cm。实验组：选用倾斜角度摄影和平行移动摄影，分别进行两幅和三幅拼接图像的摄影，每次摄影照射野应包含对应标尺的标记，摄影距离120cm。物一台距离3．5cm；然后将相应图像裁剪拼接。评价拼接图像的标尺长度与单幅摄影时标尺影像长度与放大率是否存在差异。结果：标尺影像长度为（39．557±0．382）cm，放大率为（1．130±0．001）。采用单因素方差分析（ANOVA），实验组和对照组的标尺影像长度差异无统计学意义（F=2．359，P=0．056）；采用Welch检验，模型影像放大率与标尺影像放大率差异无统计学意义（W=69．600，P=0．126）。结论：倾斜角度摄影和平行移动摄影的拼接图像与单幅摄影图像的放大率基本一致。倾斜角度摄影比平行移动摄影更能显示X线解剖结构的一致性。数字化X线摄影系统人工拼接图像能真实、客观显示人体影像信息，操作方便、可靠，为临床提供准确影像资料。

Validation of Image Mosaic with Digital Radiographic System

Objective： To investigate the validity of image mosaic with digital radiographic system. Methods： In control group, the studied model was X-rayed with the central mark of scale penetrated vertically by the centerline of X-ray -tube and both ends of the scale included in the radiation field. The distance of photography was 120 cm and model-to-table distance was 3.5 cm. In experiment group, two or three pictures using oblique or parallel photography were taken for image mosaic, with a marker scale included in each picture. The distance of photography was 120 cm and model-to-table distance was 3.5 cm. We investigated if differences existed in the length of scale, magnification rate of the model and of the scale, between the mosaicked and single photographic images. Results： The length of the scale imaging was （39.557±0.382） cm with the rate of magnification being （1.130±0.001 ）. The length of scale on images was not statistically different between the control and experiment groups as found by ANOVA （F=2.359, P=0.056）. The rates of magnification of the model and scale were not statistically different between the control and experiment groups as found by Welch test （W=69.600, P=0.126）. Conclusion： Mosaicked images from oblique or parallel photography yielded rates of magnification comparable to those in single photographic images. Oblique X-ray photographing appeared better than parallel method in display of anatomic structures. Image mosaic completed by digital radiographic system can be shown to provide realistic, objective data of the human anatomy with ease and reliability in manipulations, and therefore may be a source of accurate imaging for clinicians.