Terahertz Imaging in Biomedical Detection: Principles, Applications, and Challenges

Terahertz (THz) imaging has emerged as a powerful technique with great potential for biomedical applications. This review focuses on its rationale, strengths, limitations, and recent advances. Terahertz imaging, with low photon energy, enables non-ionizing and non-invasive detection. Terahertz is sensitive to temperature, polar molecules such as water, and hydrogen bonds. Cancerous cells have loose structures, higher water content, and more united vibrational properties than healthy cells. Therefore, THz imaging is susceptible to malignant tissues. Complementary techniques such as nanoparticle injection, thermal modulation (heating and freezing), and methylation can improve THz imagings ability to detect breast cancer, epidermoid carcinoma, gastric cancer, diabetes, and skin cancer(melanoma). However, it still faces challenges, e.g. limited penetration depth, low signal-to-noise ratio, and slow acquisition speed. Advances in terahertz metallic tips, single-pixel cameras, offer new insights for overcoming these limitations. The paper also mentioned the convergence of terahertz imaging with other techniques, named hybrid systems, and the development of new data processing methods. Overall, terahertz imaging has the potential to revolutionize biomedical diagnosis and treatment.