As a medical engineer with an interest in imaging methods (especially those using ultrasonics), I welcome this initiative and I should like to have the opportunity to draw the attention of the working group to the need to develop nano-sized particles and "nanobubbles" for use as (targetted) contast agents, and to develop piezoelectric transducer materials of high homogeneity for use in ultrasonic transducer arrays.

With kind regards

Professor P N T Wells FRS FREng
Department of Clinical Medicine
Bristol University
UK