Terahertz scanning can be performed in either transmission or reflection geometry, the latter being more suited to oral healthcare. At each position within a scan an entire terahertz waveform is acquired containing depth information, from which time of flight and absorption information can be extracted. The images can be reconstructed to show cross sections of the sample in three different orthogonal orientations, and also 3-dimensional reconstructions.
METHOD: In an initial pilot study we have scanned a number of samples in vitro, including normal mandibular bone, teeth and associated soft tissues and dental restorations. We have also scanned diseased tissues, namely squamous cell carcinoma of the tongue, malignant bone, carious enamel and dentine. RESULTS: The terahertz images show good contrast between healthy and diseased tissue. For some of the specimens, we have correlated the terahertz images with subsequent histological analysis.
CONCLUSION: Our observations demonstrate that there is great potential for terahertz imaging of healthy and diseased oral hard and soft tissues. Further work is required to substantiate these initial results.