Nanobiotechnology for health-care

Restoration of the protons spatial distribution for different types ratios of the biological tissues
Netreba A.V., Komarov A.O., Pershukov I.O.
Faculty of Radiophysics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv. Volodymyrska Street, 64/13, Kyiv-01601, Ukraine. 
E-mail: avn@univ.kiev.ua

For the analysis of the internal structure of biological tissues in MRI the complete spatial distribution of protons is reconstructed. Due to the use of a successively repeating pulse sequence, a spatially dependent phenomenon of nuclear magnetic resonance for protons is formed. In this case, the secondary emission of the free induction signal can be represented as
,     (1) 
- proton density, T1 spine-lattice and T2- spine-spine relaxation times, TE - time of spine echo,  TR - time of the pulse sequence. The obtained distribution of characteristics can be weighted by the proton density, spin-spin or spin-lattice relaxation time. An analysis of spin-spin or spin-lattice relaxation allows one to identify biochemical processes for a living objects, especially in super resolution technologies [1-2]. For biological tissues of the brain, such as gray matter, white matter end edema spine-lattice time T1 is equal to 920, 785 and 1100 ms respectively. For the same brain tissues spine-spine relaxation time T2 is equal to 100, 90 and 110 ms respectively. During the measurements, the values of the parameters TE and TR determine the type of weighting of the final proton distribution. The measured secondary reradiating signal (1) is an integral characteristic that reflects the dynamics of the precession of a large number of protons. In this paper a technique for selecting the parameter TE and TR, adapted to the molecular environment of protons within the voxel as the minimum volume of the study is proposed. It is shown that under such conditions, a more accurate interpretation of the results of indirect measurements of signals is made.

1.	Ambrosanio M., Baselice F., Ferraioli G., Lenti F., Pascazio V.  Intra voxel analysis in magnetic resonance imaging // Magnetic Resonance Imaging.-2017.-37,-P. 70-80.
2.	Netreba A.V., Komarov A.O. Influence of the Transverse Gradient Magnetic Fields Instability to Reconstruction in MR Imaging // Proc. of IEEE Intern. Young Scientists Forum on Applied Physics and Engineering.-2017.