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ALT'23 The 30th International Conference on Advanced Laser Technologies
B-O-1
Study of the changes in the scattering properties of white matter under the influence of ionizing radiation
K.A. Achkasova1, L.S. Kuhnina1, A.A. Moiseev2, A.Yu. Bogomolova1, N.D. Gladkova1
1- Privolzhsky Research Medical University, 603005, N. Novgorod, Minin andPozharsky sq., 10/1 2- Institute of Applied Physics of RAS, 603155, N. Novgorod, Ulyanova str., 46
Main author email address: [email protected]
Malignant neoplasms of the brain cause more than 250 000 deaths worldwide each year [1]. The combined treatment of brain tumors includes surgical resection, chemo- and radiotherapy. Intraoperative study of the white matter morphology in the perifocal zone of the tumor is necessary to accurately determine the boundaries of tumor resections. However, it must be understood that in the case of re-resection of the tumor, the white matter tissue can be damaged not only due to tumor growth, but also due to the use of radiation therapy [2], which causes more difficulties in distinguishing between tumor and normal brain tissues. Thus, there is a need to develop new methods for diagnosing white matter changes that occur during radiation therapy that could be used during surgical intervention. Optical coherence tomography (OCT) is a promising tool for study the white matter morphological features in brain tumors based on its scattering properties [3,4]. That is why the aim of the study was to evaluate the effect of ionizing radiation on the scattering properties of the white matter of the brain using OCT.
The study was performed on Wistar rats divided into control group and the group exposed to X-Rays (once at a dose of 15 Gy per region of the right hemisphere of the brain). At 7 time points since the experiment had started (each 2 weeks), the animals were euthanized, followed by an OCT study and an immunohistochemical study of the frontal sections of the brain. Numerical analysis of OCT data was carried out by calculating the attenuation coefficient and building of en-face color-coded optical maps. The corpus callosum was chosen as the region of interest.
As a result of the study, we discovered statistically significant decrease of attenuation coefficient values in corpus callosum at 3 time points. At 2 weeks after irradiation, we registered changes of attenuation coefficient values in the irradiated hemisphere, while at 6 and 12 weeks after the X-Rays exposure the attenuation coefficient values were decreased both in the irradiated and contralateral hemisphere. The detected changes were confirmed histologically: at the stage of 2 weeks after irradiation, a moderate edema occurred only in the area of the irradiated hemisphere, while at the stage of 6 and 12 weeks it was also found in the contralateral hemisphere and was characterized by significant severity, which indicates the spread of the process along the course of myelinated nerve fibers.
Thus, in the course of this study, morphological changes in the corpus callosum resulting from exposure to ionizing radiation were recorded, which were characterized by a decrease in its scattering properties, detected by OCT. The study was financially supported by the Russian Science Foundation, grant No. 23-25-00118.
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[2] D. Antoni, L. Feuvret, J. Biau, et al., Radiation guidelines for gliomas, Cancer radiotherapie, vol. 26, pp. 116-128, (2022).
[3] E. Kiseleva, K. Yashin, A. Moiseev, et al., Accurate detection of white matter tracts: mapping of human brain eloquent areas with cross-polarization optical coherence tomography, Proceedings of SPIE, vol. 11360, pp. 113600C, (2020).
[4] K. Achkasova, A. Moiseev, K. Yashin, et al., Nondestructive label-free detection of peritumoral white matter damage using cross-polarization optical coherence tomography, Frontiers in Oncology, vol. 13, pp. 1133074, (2023).
