Friedrich: Milling a Lens that Goes Straight to the Heart
An ultrasound device that features
a lens only one millimeter across could help prevent coronary arteries
from re-blocking following bypass surgery.
The lens, milled by Professor
Craig Friedrich (ME-EM), is an essential part of an ultrasound system
developed in cooperation with Professor Robert Keynton of the University
of Louisville. The integrated miniature acoustical lens-transducer system,
as it is called, measures the dragging force of blood against the walls
of arteries as it goes surging by.
"For instance, when surgeons
do a graft, they could use it to make sure the blood is flowing by smoothly,
with no turbulence," Friedrich said. Turbulence may cause inflammation
on the inside of arteries, which can result in more plaque build-up and
subsequent blockage.
The lens focuses very intense
ultrasound waves on the interior walls of blood vessels to measure the
"shear stress" of the blood flow. Currently, the system is being
used to investigate whether this shear stress causes arterial re-blockage
following coronary bypass surgery.
What makes this lens special
is not only its size--it's as thick as two strands of human hair--but
also how it's made. Using micromachining techniques to make tiny lenses
is nothing new, but keeping them in shape is.
Most errors occur when the
lens is attached to the transducer, the part of the system that changes
sound waves to electrical energy. This time, the researchers managed to
create the perfect lens by milling it out after the system was assembled.
The device holds promise in
a number of different areas, including detecting small tumors. And Friedrich
says more breakthroughs are in the wings.
"This project started
about six years ago, and we've made a lot of progress on tiny acoustic
devices since then," he said.
Their work is being featured
in an upcoming edition of Biophotonics International and appears on the
BBC Web site http://news.bbc.co.uk/hi/english/health/newsid_1892000/1892273.stm.
