APPLICATION OF SUBSTITUTION METHOD FOR RESTORATION OF DISTRIBUTION OF COEFFICIENT OF NONLINEARITY OF BIOTISSUES ON THE BASIS OF SECONDARY FIELD OF THE PASSED ACOUSTIC RADIATION
Abstract
It is known that ultrasonic methods of visualization of internal structures of biological ob-jects are safer in comparison with x-ray and magnetic resonance imaging and are characterized by fewer restrictions for conducting research. However, a significant disadvantage of such meth-ods is not high enough resolution. This is because most existing ultrasound diagnostic systems are based on the laws of linear acoustics. One of the promising areas of research is the development of methods for visualizing the internal structures of biological objects and determining the size and boundaries of inhomogeneities based on the nonlinear interaction of the acoustic field withbiological tissues. In this paper, we consider a method for improving the accuracy of the process of localization of heterogeneity in a biological object. To solve this problem, we use a replacement method based on calculating the ratio of the distribution of the pressure amplitude of the second-ary field of an acoustic wave that passed through a biological object that has pathological inclu-sions to the pressure of the secondary field of a wave that passed through a homogeneous medium with known nonlinear characteristics. The article presents an expression describing the distribu-tion of the acoustic pressure of the field of secondary sources, on the basis of which the calcula-tions were performed. For mathematical modeling, a model of a biological object consisting of muscle tissue and pathological inclusions (fibroids) was used. In the framework of this study, the ratio of the secondary field pressure change for this model and a homogeneous reference medium with known characteristics is calculated. The obtained data is presented in the form of contour graphs that reflect the location of the inhomogeneity. The results of the calculations showed a greater efficiency of using the substitution method for the process of determining the location of inhomogeneous inclusions in the bioobject model compared to visualization methods based on restoring the pressure distribution of the secondary acoustic field. It is shown that the use of the substitution method makes it possible to more accurately determine the boundaries of inhomogeneities. Therefore, the substitution method can be used to obtain projection data and restore the distribution of an acoustic nonlinear parameter in a flat section of a biological object.
References
2. Akopyan V.B., Ershov Yu.A. Osnovy vzaimodeystviya ul'trazvuka s biologicheskimi ob"ektami [Fundamentals of interaction of ultrasound with biological objects]. Moscow: Izd-vo MGTU im. N.E. Baumana, 2005.
3. Fatemi M., Greenleaf J.F. Real-time assessment of the parameter of nonlinearity in tissue us-ing «nonlinear shadowing», Ultrasound in Med. & Biol., 1996, Vol. 22, No. 9, pp. 1215-1228.
4. Gong X.F., Yan Y.S., Zhang D., Wang H.L. The study of acoustic nonlinearity parameter to-mography in reflection mode, Acoustical Imaging, 2003, Vol. 27.
5. David E. Goertz, Martijn E. Frijlink, Nico de Jong, Antonius F.W. van der Steen. Nonlinear Contrast Intravascular Ultrasound. Ultrasound and Carotid Bifurcation Atherosclerosis. Springer-Verlag London Limited, 2012, pp. 137-153.
6. Laguta M.V. K voprosu resheniya obratnoy zadachi akusticheskoy tomografii [To the question of solving the inverse problem of acoustic tomography], V Vserossiyskaya molodezhnaya shkola-seminar «Innovatsii i perspektivy meditsinskikh informatsionnykh sistem IPMIS-2016», 19-22 dekabrya 2016, g. Taganrog [V all-Russian youth school-seminar "Innovations and prospects of medical information systems IPMIS-2016", December 19-22, 2016, Taganrog], pp. 65-68.
7. Xiufen Gong, Dong Zhang, Jiehui Liu, Huanlei Wang, Yongsheng Yan, and Xiaochen Xu. Study of acoustic nonlinearity parameter imaging methods in reflection mode for biological tissues, Acousti-cal Society of America, 2004, pp. 1819-1825.
8. Demin I.Yu., Pronchatov-Rubtsov N.V. Sovremennye akusticheskie metody issledovaniy v biologii i meditsine: uchebno-metodicheskiy material po programme povysheniya kvalifikatsii «Khranenie i obrabotka informatsii v biologicheskikh sistemakh» [Modern acoustic research methods in biology and medicine: educational and methodological material for the advanced training program "Storage and processing of information in biological systems"]. Nizhniy Novgorod, 2007, 121 p.
9. Rudenko O.V., Soluyan S.I. Teoreticheskie osnovy nelineynoy akustiki [Theoretical founda-tions of nonlinear acoustics]. Moscow: Nauka, 1975, 288 p. 10. Chernov N.N., Laguta M.V., Varenikova A.Yu. Method. of detection of pathological areas in biotissues on the basis of determination of characteristics of harmonic components in an ultra-sonic wave, Discovery, 2019, Vol. 55 (280), pp. 120-124.
11. Chernov N.N., Laguta M.V., Varenikova A.Yu. Research of Appearance and Propagation of Higher Harmonics of Acoustic Signals in the Nonlinear Media, Journal of Pharmaceutical Science and Research, Vol. 9, No. 11. Available at: http://www.jpsr.pharmainfo.in/ is-sue.php?page=99.
12. Preobrazhenskiy S.V., Preobrazhenskiy V.L., Perno F., Bu Matar O. Diagnostika neodnorodnosti nelineynogo parametra akusticheskoy sredy s pomoshch'yu obrashcheniya volnovogo fronta ul'trazvuka [Diagnostics of inhomogeneity of the nonlinear parameter of the acoustic medium using the reversal of the ultrasound wave front], Akusticheskiy zhurnal [Akusticheskij zhurnal], 2008, Vol. 54, No. 1, pp. 20-25.
13. Zagray N.P. Nelineynye vzaimodeystviya v sloistykh i neodnorodnykh sredakh: monografiya [Nonlinear interactions in layered and inhomogeneous media: monograph]. Taganrog: Izd-vo TRTU, 1998, 433 p.
14. Chernov N.N, Mikhralieva A.I, Zagray N.P., Al'-Saman A.Kh. Opredelenie uprugikh svoystv biologicheskikh sloistykh sred na osnove nelineynogo vzaimodeystviya akusticheskikh voln [Determination of elastic properties of biological layered media based on nonlinear interaction of acoustic waves], Inzhenernyy vestnik Dona [Engineering Bulletin of the Don], 2016, No. 3. Available at: ivdon.ru/ru/magazine/archive/n3y2016/3735.
15. Burov V.A., SHmelev A.A., Zotov D.I. Prototip tomograficheskoy sistemy, ispol'zuyushchey akusticheskie nelineynye effekty tret'ego poryadka [Prototype of a tomographic system using acoustic nonlinear effects of the third order], Akusticheskiy zhurnal [Akusticheskij zhurnal], 2013, Vol. 59, No. 1, pp. 31-51.
16. Chernov N.N., Laguta M.V., Varenikova A.Yu. Chislennoe modelirovanie polya vtorichnykh istochnikov akusticheskoy volny pri prokhozhdenii cherez biologicheskuyu sredu [Numerical simulation of the field of secondary acoustic wave sources when passing through a biological medium], Modelirovanie, optimizatsiya i informatsionnye tekhnologii [Modeling, optimization and information technologies], Vol. 6, No. 33, pp. 40-49.
17. Rudenko O.V. Nelineynye volny: nekotorye biomeditsinskie prilozheniya [Nonlinear waves: some biomedical applications], Uspekhi fizicheskikh nauk [Success of physical Sciences], Vol. 177, No. 4. 18. Chernov N.N., Zagray N.P., Laguta M.V., Varenikova A.Yu. Research of appearance and prop-agation of higher harmonics of acoustic signals in the nonlinear media, Journal of Physics: Conference Series, 2018, Vol. 1015 (3), pp. 032-081.
19. Fizika vizualizatsii izobrazheniy v meditsine [Physics of image visualization in medicine]: in 2 vol. Vol. 2: transl. from engl., ed. by S. Uebba. Moscow: Mir, 1991, 408 p.
20. Korneev Yu.A., Korshunov A.P., Pogadaev V.I. Meditsinskaya i biologicheskaya fizika [Medi-cal and biological physics]. Moscow: Nauka, 2001, 247 p.
