LASER TOMOGRAPHIC IMAGES AND ULTRASONIC TOMOGRAPHIC IMAGES ON THE PERIODONTAL TISSUES

用于生物组织的功能监测和形态检测的光学和声学传感方法最近受到广泛关注。光和声音是非电离性质的，相对安全，具有对患者的结构和功能状态进行非侵入性和非破坏性监测的能力。CDI方法在检测相干保持和组织散射最小的光子方面具有高灵敏度和方向选择性。在从超声波探头发送的声波在其中传播的生物组织中，在声速不同的组织中的边界中产生回波。超声层析成像是检测组织中不同声学介质层的回波，本研究设计了测量系统，获得了亚毫米级分辨率的牙齿和牙周组织的光学和声学层析图像。10颗人类拔牙 ...更多信息 用于光学检测。采用连续波、单频、半导体激光器（532 nm）作为光源。入射光束的直径为200 μ m。将来自牙齿相对侧的透射光束叠加在参考光束上，并照射在产生20 MHz中频的光电二极管上。牙齿被安装在一个平行旋转步进和扫描进行T-R模式类似于传统的计算机断层扫描。图像重建采用滤波反投影法。将牙齿的激光CT图像与显微镜横截面进行比较并进行评估。水平方向图像反映牙齿、髓腔和根管的内部结构，并可定位透明牙本质的位置。使用声探头通过延迟线将高频超声源（20 MHz）应用于牙槽部分上方的下颌骨额部皮肤。延迟线连接到探头的辐射口，将从活体组织获得的回波传输到接收器，同时将声音传输到组织。声探头上与皮肤连接的部分的直径为2 mm。声束在牙周组织中的传播在牙周组织边界处产生回声。将探针安装在由程序化测序仪自动控制的旋转-旋转（T-R）臂上。旋转步进器逐渐移动并定位探头，以在面部皮肤上水平扫描。气动平移缸使探针向皮肤移动，使探针在恒定的力下与皮肤尖端接触。在示波器上测量回波波形。在牙槽骨唇面上，在比表皮和牙龈组织更深的位置，观察到一个密集的尖锐棘突，而在靠近表皮的软组织和粘膜上，观察到大量的相对较小的棘突。在从表皮到牙槽骨的范围内具有二维分辨率的声学数据可以从这样的回波波形构造，这些回波波形在计算机显示器上按顺序水平排列。少

Optical and acoustic sensing methods for the functional monitoring and morphological inspection of biological tissues are recently receiving widespread attention. Light and sound being non-ionizing nature, are relatively safe have capabilities for the non-invasive and non-destructive monitoring of the structural and functional states of patients. The CDI method possesses high sensitivity and directional selectivity in detecting the coherence retaining and the least scattering photons from tissues. In the biological tissues in which the acoustic wave sent from ultrasonic probe is propagated, the echo is generated in the boundary in the organization in which the sound velocity differs. The ultrasonic tomography detects the echo got from the layer which differs as acoustic medium in the tissues.In this study, we designed the measurement system to obtain optical and acoustic tomographic images for human teeth and periodontal tissues with submillimeter resolution. Ten human extracted teeth … More were used for the optical detection. Continuous wave, single frequency, semiconductor laser(532nm) were used as the light source. The diameter of the incident beam was 200 μ m. The transmitted beam from opposite side of the tooth was superposed on the reference beam and impinged on a photodiode generating an intermediate frequency at 20MHz. The tooth was mounted on a translational-rotational stepper and the scanning was performed in the T-R mode similar to that of the conventional computed tomography. The image reconstruction was done using the filtered back projection. Laser CT images of teeth were compared to the microscopic cross sections and assessed. The internal structure of teeth, pulp cavities and canals were reflected in the horizontal images, and also the site of the transparent dentine could be located.The acoustic investigation by the ultrasonic wave for oral tissue was carried out for the volunteer. High frequency, ultrasound source (20 MHz) was applied to the mandible frontal skin over the alveolar portion using the acoustic probe via delay line. The delay line with the connection to the irradiation mouth of the probe transmitted the echo which was obtained from the live tissue to the receiver, while the sound was transmitted to the tissue. The diameter of the attached portion to the skin on the acoustic probe was 2mm. The transmitted sound beam to the periodontal tissue generated the echoes on the boundary between different tissues. The probe was mounted on a translational-rotational(T-R) arms which was controlled automatically by programmatic sequencer. The rotational stepper gradually moved and located the probe to scan horizontally on facial skin. The pneumatic translational cylinder made the probe move toward the skin, and it was made to contact the tip of prove to the akin in the constant force. The echo waveforms were measured on the oscilloscope. An intensive sharp spike which was generated on the labial surface of the alveolar bone which was located in the place which was more deep than the epidermis and gingival tissue was observed, while the comparative small spikes which was produced on the soft tissue and mucosa which were near for the epidermis were observed in great numbers. Acoustic data with a Two-dimensional resolution in the range from epidermis to alveolar bone could be constructed from such echo waveforms which were horizontally arranged in the order on the computer display. Less