M.K. Khodzitsky1

1 Limited Liability Company «Terahertz Photonics» (St. Petersburg, Russia)
1 khodzitskiy@yandex.ru

Early and accurate diagnosis of cancer is crucial to reduce the high mortality rate of this disease. Therefore, it is so important to detect tumor markers in biological samples quickly and with high sensitivity in clinical laboratories. Skin cancer is usually diagnosed by a dermatologist who performs a visual examination and confirms his findings with a biopsy. The surgeon then removes the tumor with a large margin to ensure its complete excision. A subsequent biopsy allows checking whether the tumor has been completely removed. Depending on the results, additional surgery may be required. There is an urgent need to develop a safe and non-invasive in vivo diagnostic method for detecting skin cancer at an early stage. Such a method would allow for a more accurate determination of the presence of a tumor and timely measures for its treatment.

The aim of the study is to develop a theoretical approach of method for non-invasive diagnostics of skin cancer based on terahertz (THz) ellipsometry in reflection mode.

It has been theoretically demonstrated that by measuring complex reflection coefficients for s- and p-polarized THz pulsed radiation from biological tissue and calculating on their basis the dispersions of the azimuthal and ellipticity angles of the reflected THz wave, it is possible to non-invasively differentiate cancerous and healthy tissue due to the difference in the permittivity tensor components.

The proposed method allows diagnosing malignant skin tumors in the reflection mode at early stages due to the difference in the permittivity tensor of cancerous and healthy biotissue in the THz frequency range and, as a consequence, the difference in the azimuth angle and the ellipticity angle of the reflected THz wave from the tissues under study. This effect is caused by the presence of ordered anisotropic structures, such as collagen fibers, and gyrotropic structures, such as sweat glands, in healthy skin biotissue and their disruption in oncological biotissue. Thus, THz pulse ellipsometry is a relevant non-ionizing non-invasive technique for diagnosing skin cancer and can potentially become a new "gold standard" for primary diagnostics of the disease.

Khodzitsky M. K. Noninvasive skin cancer diagnostics method based on terahertz ellipsometry. Biomedicine Radioengineering. 2026. V. 29. № 3. P. 81–86. DOI: https:// doi.org/10.18127/ j15604136-202603-14 (In Russian)

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