Nano ilacin tümörlü dokuya mikrokabarcik ile taşinimi

This dissertation explores the dynamics of spherical and nonspherical microbubble oscillations in microvessels and their implications for ultrasound-mediated therapeutic applications. The study focuses on microvessel properties, an aspect often neglected in the literature, and their impact on microbubble oscillation and stability. Simulations were conducted across various vessel and bubble properties and acoustic field parameters to analyze their effects on the resulting bubble surface area and shear stress on the microvessel wall where high shear stress values cause tissue damage (> 800 Pa). In particular, the maximum shear stress reaches 30 kPa with an acoustic field pressure of 1.5 atm at 8 MHz. The maximum bubble surface area should be 900 µm2 at resonance for Newtonian liquid, which affects the drug loading capacity and diffusion rate. Different constitutive models are applied to examine the effects of blood's non-Newtonian properties. For the bubble shell, Neo-Hookean model replaces simpler linear models, revealing significant deviations; for example, the difference between linear and nonlinear shell models reaches 60% when the pressure amplitude reaches 2.5 atm. In the literature, most studies use complex models, whether necessary or not. However, in this dissertation, a parametric range is obtained, where simple models can be used to prevent unnecessary long code runs. These insights provide a foundation for optimizing ultrasound-mediated drug delivery by carefully tuning bubble characteristics and acoustic settings to maximize therapeutic efficacy while minimizing potential vascular injury. The model also includes bubble-bubble interactions to determine the minimum distance to prevent collapse. Near resonance, this distance is found to be 12 µm. Contour maps for different shell and acoustic field properties are obtained to show where the ultrasound-mediated bubble application is safe or unsafe for the treatment application. Here, three criteria are considered: bubble surface area, wall shear stress, and distance between bubbles.