CC BY
23B-I-28
THz pulsed spectroscopy and solid immersion microscopy of brain gliomas: A road toward intraoperative THz diagnosis
K.I. Zaytsev1'2'3 *. A.A. Gavdush1'2'3' N.V. Chernomyrdin1'2'3, I.N. Dolganova2'3'4' P.V. Nikitin2'5' G.A. Komandin1' I.V. Reshetov6' and V.V. Tuchin7'8'9
1 — Prokhorov General Physics Institute of the Russian Academy of Sciences, Russia 2 — Institute for Regenerative Medicine, Sechenov University, Russia 3 — Bauman Moscow State Technical University, Russia 4 — Institute of Solid State Physics of the Russian Academy of Sciences, Russia 5 — Burdenko Neurosurgery Institute, Russia 6 — Institute for Cluster Oncology, Sechenov University, Russia 7- Science Medical Center, Saratov State University, Russia 8 — Institute of Precision Mechanics and Control of the Russian Academy of Sciences, Russia 9 — National Research Tomsk State University, Russia *E-mail: kirzay@gmail.com
Terahertz (THz) technology offers novel opportunities in label-free diagnosis of malignant and benign neoplasms with different nosologies and localizations, relying on the strong sensitivity of THz waves to the content and state of tissues water [1-3]. Recently, a potential of THz spectroscopy and imaging in the intraoperative diagnosis of human brain gliomas with the different World Health Organization (WHO) grades was uncovered [4]. In our research, we focused on studies of the effective THz optical properties and THz microscopic images of the intact tissues and gliomas ex vivo, involving both the ex vivo tissues from human and those from rats. We were the first to demonstrate statistically-significant differences between the THz response of intact tissues and WHO Grades I-IV human brain gliomas [5]. Next, we described the picosecond relaxation dynamics of intact tissues and gliomas from humans using both the double-Debye and double-overdamped-oscillator models of a complex dielectric permittivity [6]. Relying on these models, an increased water content in a tumor was found to be the main origin of the observed contrast between intact tissues and a tumor in THz spectra and images. Finally, using the diffraction limited THz pulsed spectroscopy and the innovative 0.15^-resolution THz solid immersion microscopy [7-8], we studied, for the first time, the THz response of monografl glioma model 101.8 from rats ex vivo, both in freshly-excised and paraffin-embedded forms [9]. The observed results justified a contrast between intact tissues and a tumor in the THz range. Moreover, it revealed heterogeneous character of brain tissues at the THz-wavelength scale, that agrees well with tissue measurements involving optical coherence tomography in the near-infrared range [10]. Heterogeneity of the intact tissues was attributed to the distinct response of white and gray matters, as well as to other neurovascular structures of the brain. In turn, that of a tumor mostly originates owing to the presence of necrotic debris and haemorrhages. Our findings demonstrated that THz technology hold strong potential in the intraoperative diagnosis of human brain tumors. However, a number of fundamental and applied problems should be solved before translation of THz instruments to a clinical practice.
This work was supported by the Russian Science Foundation, Project # 17-79-20346.
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