Enhanced ULtrasound Visualization of Brachytherapy Seeds by a Novel Magnetically Induced Motion Image Method

摘要

We report our progress in developing Magnetically Induced Motion Imaging (MIMI) for unambiguous identification and localization brachytherapy seeds in ultrasound images. In this period we have developed finite-element models for calculating the force on a soft ferromagnetic seed core due to geometrical anisotropy and compared two candidate seed geometries to determine the sensitivity of torque to geometry. We have created a finite element model of a prototype coil configuration for seed vibration and demonstrated the ability of this coil configuration to steer the magnetic field in a manner suitable for improving MIMI imaging. We present our first 3D reconstructions of seeds embedded in a tissue-mimicking phantom; the reconstructions show good agreement with previous simulations. The insensitivity of the vibration Doppler signal to ultrasound beam angle and ultrasound frequency is experimentally demonstrated.