Biomedical Engineering Reference
In-Depth Information
that have occurred in biology and medicine have depended on new methods that
are the result of fundamental discoveries in many different fields. A number of
individuals with expertise in different disciplines would collaborate in solving a
problem related to bioengineering. Major contributions of bioengineering includ-
ing hip joint replacement, artificial articulated joints, magnetic resonance imaging,
heart pacemakers, arthroscopy, heart-lung machines, angioplasty, bioengineered
skin, time-release drug capsules, and kidney dialysis have evolved through success-
ful collaborations between medical practitioners and many disciplines including
physics, mathematics, chemistry, computer sciences, and engineering. Significant
improvements in computational tools and information technologies have already
played a greater role with the emergence of telemedicine. The number of medical
device establishments registered at the U.S. Food and Drug Administration (FDA)
was nearly 11,000 in 2004. To understand the interdisciplinary nature of bioen-
gineering, the history behind three significant contributions are described in the
following subsections.
1.3.1 DevelopmentofBiomedicalImaging
Various medical imaging modalities provide complementary windows through
which most of the organs and their functions can be visualized. It began many
centuries ago with the discovery of various fundamental concepts in physics, bi-
ology, and chemistry. In 1668, Antoni van Leeuwenhoek, a Dutch scientist and
builder of microscopes, confirmed the discovery by Italian anatomist Marcello
Malpighi of capillary systems using a simple magnifying lens. He demonstrated
how the red corpuscles circulated through the capillaries of a rabbit's ear and the
web of a frog's foot. In 1674, Leeuwenhoek gave the first description of red blood
corpuscles (RBC). He then discovered the motion of bacteria (he referred to them
as animalcules) and sperm cells. In 1729, British pensioner Stephen Gray distin-
guished conductors of electricity from nonconductors. In 1750, Benjamin Franklin
defined positive and negative electricity. In 1800, Italian physicist Alessandro Volta
constructed the first electrical battery. In 1827, German physicist Georg S. Ohm
formulated Ohm's law, stating the relation between electric current, electromotive
force, and resistance. British physicist and chemist Michael Faraday and American
scientist Joseph Henry discovered electromagnetic induction (i.e., refined the sci-
ence of electromagnetism to make it possible to design practical electromagnetic de-
vices). In 1873, Scottish mathematician and theoretical physicist James C. Maxwell
published his famous four equations describing electrical and magnetic phenomena
in the topic
Treatise on Electricity and Magnetism.
In 1893, Joseph J. Thomson,
a British physicist widely recognized for discovering electrons, published a supple-
mentary volume to Maxwell's treatise, describing in detail the passage of electricity
through gases. Further, he developed the cathode-ray tubes with the help of some
graduate students.
Significant change occurred in 1895 when German physicist Wilhelm C. Roent-
gen accidentally discovered that a cathode-ray tube could make a sheet of paper
coated with barium platinocyanide glow, even when the tube and the paper were
in separate rooms. Roentgen decided that the tube must be emitting some sort of
penetrating rays. He named them X for unknown. Shortly afterward, Roentgen
