Effects of discrete blood vessels in ultrasound interstitial heating from FEA modeling

In this presentation, the authors report modeling heating of tissue with ultrasound interstitial applicator array. Their 3-D FEA computation of heating patterns due to four-applicator array evaluates effects of discrete blood vessels around the applicators in brain tissue. In the modeling, the number of blood vessels around an applicator varied from three to six. Several sizes of blood vessels are discussed. The smallest and the largest vessels were of 0.367 and 1.1 mm average diameter. The authors considered also a bed of vessels of mixed size. They found that small vessels in vicinity of the applicators do not influence significantly the heating patterns. Temperature around them remains high enough to cause their denaturation. The large blood vessels at the periphery of treatment region reduce substantially the region both in the radial direction from the array center and in the axial direction at the region center