Characterization of HIFU fields inside of a tissue-mimicking HIFU phantom

The use of a tissue-mimicking, scatterer-free polyacrylamide gel phantom for HIFU has been previously described [1]. This transparent material combines with a marker with an absorption of 0.6 dB/cm MHz which turns opaque when the temperature exceeds 65 °C. After a brief review of the material properties and their validation, we discuss typical uses of the phantom as part of QA and protocol development and discuss comparisons between phantom and free-field measurements in water at high intensities. Comparisons are also made to new investigations where in situ pressures have been measured by embedding a fiber-optic probe into a sample of a phantom material. [1] S. Howard, J. Yuen, P. Wegner, and C. Zanelli, “Characterization and FEA simulation for a HIFU phantom material,” in IEEE Ultrasonics Symposium (2003), pp. 1270–1273.