AbstractID: 11948 Title: Systems and probes for ultrasound molecular imaging
Specialized ultrasound systems and targeted microbubbles optimized for vascular
molecular imaging continue to advance. The development of methods for sensitive and
selective imaging of adherent, targeted contrast agents requires improvements in both the
physical systems and probes. We have developed transducers and signal processing
techniques to maximize transducer bandwidth and integrated the components with a
clinical ultrasound scanner. The transducer integrates low and high-frequency arrays;
the center-row high-frequency array is surrounded on each side with confocally-focused
low-frequency arrays. By transmitting from the low-frequency (1.6 MHz) arrays and
receiving through the high-frequency (7 MHz) array, harmonic microbubble echoes can
be detected and distinguished from the surrounding tissue. Further, by combining echoes
over a pulse train, a targeted agent to free agent signal ratio of 15~22 dB can be obtained
without waiting for agent clearance. Further, we report on radiolabeling methods to fully
assess microbubble biodistribution with and without molecular targeting or insonation.
We find that microbubbles are rapidly accumulated within the liver and spleen, although
a small (but significant) mass of the microbubble shell accumulates as a result of local
insonation.
We acknowledge the support of NIH CA 103828 and CA 112356.