temperature of tissue
biological object model
O.R. Nikitin, V.A. Yakovlev, A.N. Danilov
Breast cancer – the most common form of malignant tumors in women. He is one of the most serious problems of modern oncology. Timely detection at an earlier stage of the malignant process and determination of its prevalence determine the tactics of subsequent treatment.
In this regard, promising the use of safe, high-performance microwave techniques to identify tumors in the mammary gland. It focuses on the preparation and conduct of the possible experimental studies on the designated topics.
Distribution of the microwave signal depends mainly on the dielectric constant, and not on the density of the medium. The dielectric constant varies from 5 to 50, while the density of soft tissue changes within a few percent. Such a wide range of variation of the dielectric constant indicates the possibility of obtaining a large contrast in the image and better identification of tissues. Moreover, the energy of microwave photons is small and does not cause ionization in biological tissues with standard intensities, so that when the microwave radiation X-rays are no inherent negative side effects.
The initial and necessary step justify the value of the described diagnostic techniques involving passive radiometry is to conduct experimental research. Modeling bioobject and tumors produced from synthetic materials or animal tissues, the physical properties of which are identical to human tissues. In particular, the design of a woman's breast can be made from zhivtnogo fat, and as a neoplasm can use a small piece of folded in several layers of pork skin. The use of such animal materials quite rightly, because that fat is the basis of real breasts, and tightly packed pigskin has the same dielectric parameters as a malignancy. For complete isolation from the influence of external factors, such as injurious radiation devices, the self-thermal radiation of people conducting the experiment, as well as the radiation of each of the objects of the environment, it is proposed to use a special anechoic chamber or its equivalent.
– with increasing depth of immersion for irregularities of all sizes the value of the luminance contrast decreases monotonically, with the steepest decline is observed with increasing immersion depth of 0.5 cm (surface layer) to 1 cm;
– the maximum depth at which can be found a large sample of graphite (2 × 2 × 1.5 cm 3) is approximately 3 cm;
– the maximum depth at which can be found the smallest sample of graphite (0.5 × 0.5 × 0.5 cm 3) is approx-imately 1 cm;
– Reducing the size of the heterogeneity reduces the magnitude of the depth of immersion, at which this hetero-geneity can be detected;
– The experimental results provide the basis for the establishment of modeling techniques (of natural and mathe-matical) of different situations, diagnosis of neoplasms of the breast, based on what can be implemented non-invasive diagnostic system neoplasms;
– the results of modeling allow to draw a positive conclusion on the possible, use for the diagnosis of neoplasms of the microwave radiometers operating in the range of high-frequency thermal radiation (37.5-50 GHz), which will dramatically increase the resolving power and, consequently, the diagnostic accuracy as opposed to now practiced by a microwave -any screening device, operating in the MHz range.