Quantitative Analysis of the Image Layer in Rotational Panoramic Radiography

点击翻译按钮获取中文摘要

To analyze the three dimensional image layer, we measured the modulation transfer function (MTF) at the anterior to TMJ region in rotational panoramic radiography.These MTFs enabled us to determine the information transfer factor (ITF) introduced by McDavid et al, and defined the layer thickness.Veraview (J. Morita Corp. Japan) was used as a panoramic x-ray unit. Dupont HiPlus/ Kodak X-OMAT RP film was exposed with 1.1mm slit width to gives slit x-ray image at the fixed kV and mA. A lead slit, 0.1mm wide and 0.1mm thick was positioned at the center of the layer in each region.The slit was moved toward the film side and the tube side at given intervals. The NTF was obtained by the method of Doi et al.When we defined the limit of the layer by the ITF of 75, the measured layer thickness was 5.74mm in the anterior, 7.35mm in the canine, 15.1mm in the molar and 20.7mm in the TMJ region, respectively. The image layer obtained by our experiment was in fair agreement with the calculated one.