METHOD: After obtaining approval from Local Ethics Committee, six fixed specimens were subjected to TPI. These routine histopathology blocks were placed face down onto the imaging window of the TPI machine. An area 20 x 20 mm was selected and scanned at a lateral resolution of 100 microns and identified by ink marks. TPI scans were compared to routine 4 micron thick formalin-fixed paraffin embedded sections stained with haematoxylin and eosin. These H+E sections were prepared in planes that matched the orientation of the TPI images. The TPI images were analysed according to the amplitude of the reflected terahertz pulse (Emax, Emin, Emin/Emax) and the time post pulse.
RESULTS: On comparing the TPI images with the histology images at low power (x4), some gross anatomical structures such as hair follicles could be delineated. Detection of tumour margin was variable and seemed to depend on the texture (refractive index) of adjacent tissue. Small tumour islands away from the main tumour were not readily identified.
CONCLUSION: The initial results show promise. Some more work to refine the image analysis is needed, together with experimenting with different software algorithms. Further work with more samples is being planned.