The British Journal of Radiology, Vol 73, Issue 875 1138-1147, Copyright © 2000 by British Institute of Radiology
Advances in ultrasound: from microscanning to telerobotics
PN Wells
Department of Medical Physics & Bioengineering, Centre for Physics and Engineering Research in Medicine, Bristol General Hospital, Bristol BS1 6SY, UK.
This paper is in memory of W V Mayneord (1902-1988). Experiments conducted
in Mayneord's laboratory were amongst the first to show that ultrasound had
diagnostic potential. Now, one in every four imaging studies uses
ultrasound. Amongst numerous contemporary advances, microscanning is
concerned with imaging subcentimetre size volumes of tissue in three
dimensions with 10-100 microns resolution. The traditional approach is by
pulse echo imaging, with a focused ultrasonic beam in the frequency range
20-100 MHz. This approach may be complemented by ultrasonic CT (to correct
for attenuation and speed variations), reflex transmission imaging (to
provide attenuation data) and synthetic aperture scanning (to decrease
imaging time). Harmonic microscanning may reduce artefacts, and elasticity
imaging may also be possible. Microscanning is likely to have applications
in pathology and in the operating room, for trackless microintervention, in
molecular biology and drug studies, and in experimental imaging of small
mammals including, in particular, the mouse. Robotics is the engineering
science concerned with devices that are able to execute tasks usually
performed by humans. Two procedures, ultrasonically guided biopsy and
ultrasonic laparoscopy, are being used to demonstrate the feasibility of
telerobotics. The approach is that of telepresence, as distinct from
supervisory control or virtual reality. Problems associated with image
compression and communications latency are identified. Although incremental
developments in medical ultrasound have resulted from clinical pull, major
advances have, in general, been due to technical push.
