Improving the use of vibro-acoustography for brachytherapy metal seed imaging: A feasibility study

Vibro-acoustography method is explored for detecting and imaging brachytherapy metal seeds in gel phantoms. In a previous paper, we have shown that some immersed objectsʹ resonance frequencies could be detected by vibro-acoustography. Here, we use this idea to optimize the vibro-acoustic excitation of two different sized brass seeds implanted in an agar gel phantom. In the experiments, the best excitation vibration frequencies were determined either by calculating fundamental resonance frequencies for each of the seeds or the experimental optimal resonance frequency of the gel. The resulting vibroacoustography images demonstrate remarkable contrast in acoustic emission amplitude compared with images obtained at nonresonance frequencies. Results suggest the possible application of vibro-acoustography for directing prostate brachytherapy seed implantation treatment.