Computational Study of Frozen Tissue Melanoma Imagining at Terahertz Frequencies

Terahertz radiation is highly absorbed by liquid water, with less than 0.0001% of the signal surviving to a depth of 1.0 millimeter at 0.45 terahertz, limiting the potential for imaging of human tissues. On the other hand, 90% of the terahertz signal survives in ice in the 0.1 to 1.0 terahertz band, opening the possibility of in-vivo imaging of skin lesions, particularly melanomas, to a depth of 5.0 millimeters by first freezing the skin in situ. Computational modelling of THz-frozen skin imaging indicates that contrast exists to differentiate melanomas from normal frozen skin on the basis of water content alone. If the melanin content of melanomas is a significant absorber of terahertz radiation, then melanin becomes the main contrast element. The modelling results justify the further exploration of the imaging technique with the study of ex-vivo frozen melanoma samples before progressing to in-vivo clinical trials.