Zp. Shulman et Aa. Makhanyok, RHEOLOGICAL FACTORS IN A THERMAL PROBLEM OF LOCAL SUPERHIGH FREQUENCYHYPERTHERMIA, International journal of heat and mass transfer, 39(3), 1996, pp. 645-652
The effect of a theological factor on a temperature field in a heterog
eneous tissue in its SHF heating is considered. A microvascular system
is presented in the form of quasiporous media and is replaced by an e
quivalent tube. The relation is found between relative change in perfu
sion, the parameter of blood viscoplasticity and hydraulic diameter of
an equivalent tube. Perfusion is found to be proportional to the cube
of a hydraulic diameter of this tube and conversely proportional to t
he value of the parameter of viscoplasticity. Their possible values an
d the range of variation with local hyperthermia (LH) are estimated. I
I is shown that the values of the parameter of viscoplasticity within
the range 1-0.06 correspond to small shear rate (5-100 s(-1)). The cha
nges in the hydraulic diameter in a normal tissue in LH may attain 20-
80%, the changes in the parameter of viscoplasticity may vary by 2.5 a
nd more limes. It is shown on the example of frequencies 2450 and 915
MHz that the theological factor of blood flow exerts a very substantia
l effect on a temperature field in tissue, especially in the presence
of a slightly perfused tumour in it.