Development of X-ray tomographic system for dento-maxillo-facial region adopted with tomosynthesis theory

这对于三维(3D)成像在人类疾病的诊断中是有用的。调谐孔径计算机层析成像(TACT)是由维克森林大学的理查德·韦伯教授提出的一种三维成像方式。这套机智系统采用的是现代综合理论。该系统从几张任意位置的射线照片(基础图像)中生成任意层析图像。许多研究人员在体外研究了其对牙槽骨病变的诊断能力。然而，这些研究中使用的TACT系统是为口腔内使用而设计的。口腔内使用是指将TACT系统的X射线传感器放置在口腔内。这可能会给患者带来不适。为了在不降低诊断能力的情况下减少患者的不适感，我们开发了用于牙槽外区域的口腔外机智系统。我们的机智系统有两种，高分辨率和广域口外机智系统。高分辨率系统由CCD数字传感器和全景层析成像仪组成。另一个广域系统由光激励荧光粉显像板和普通医用X射线发生器组成。在这两种系统中，X射线传感器都放置在离病变最近的面部皮肤表面。高分辨率系统对邻面龋病的诊断准确率高于口内X线片。广域系统对下颌阻生第三磨牙的诊断准确率与口内TACK系统基本相同。这些结果表明，我们开发的口腔外Tact系统对牙槽骨病变具有临床有效性，患者不适较少。

It is useful for three-dimensional (3D) imaging for diagnosis of human diseases. Tuned aperture computed tomography (TACT) is developed by Professor Richard Webber (Wake Forest University) that is one of 3D imaging modality. This TACT system is adopted the tomosynthetic thoorey. This system makes any tomographic images from several arbitrary positioned radiogram (basis images). Many investigators studied its ability of diagnosis for dento-alveolar lesion in vitro. TACT systems, however, used in these studies were designed for intra-oral use. Intra-oral use represents that X-ray sensor for TACT system is placed in oral cavity. This may cause patients discomfort. We developed extra-oral TACT system for dento-alveolar region to reduce patient discomfort without decreasing diagnostic ability. Our TACT system is two type, high-resolution and wide area extra-oral TACT system. The high-resolution system is consisted of CCD digital sensor and panoramic tomographic apparatus. The other wide area system consisted of photostimulable phosphor imaging plate and X-ray generator for general medical purpose. In both systems, X-ray sensor is placed at the skin surface of face nearest to the lesion. The diagnostic accuracy of approximal caries detection of the high-resolution system is better than intra-oral radiography. The accuracy of diagnosis of impacted mandibular third molors by wide area system is almost the same as that of intra-oral TACT system. These results show extra-oral TACT system that we are developed has clinical validity for dento-alveolar lesions with less patient discomfort.