Biomedical Engineering Reference
In-Depth Information
in physical science (e.g., x-ray and nuclear physics, optics, acoustics, etc.) and incorporating
the latest innovations in computer technology and data processing techniques, have not only
proved extremely useful in patient care, but they have revolutionized health care.
Over a century ago (1895), the first Nobel laureate, physicist Wilhelm Conrad Roentgen,
described a new type of radiation,
x-rays
, that ultimately led to the birth of the new medical
specialty of
, along with the medical imaging industry. Initially, these radiographic
imaging systems were very rudimentary, primarily providing images of broken bones or
contrast-enhanced structures such as the urinary or gastrointestinal systems (Figure 15.1).
However, since the 1970s, advances in imaging techniques have revolutionized the applica-
tion of radiographic imaging techniques in medical diagnosis. The same excitement that
surrounded Roentgen followed Allan Macleod Cormack and Godfrey Newbold Hounsfield.
Cormack, working in the Physics Department of Tufts University, elegantly demonstrated
the mathematical rudiments of image reconstruction in a remarkable paper published in
1963. Less than a decade later, Hounsfield, of the British firm ETD Limited, unveiled an
incredible engineering achievement: the first commercial instrument capable of obtaining
digital axial images with high-contrast resolution for medical purposes. In recognition of
the significant advances made possible by the development of computerized tomography,
Cormack and Hounsfield shared the award of the Nobel Prize in physiology and medicine
in 1979. The excitement of their discovery has not yet subsided.
Ionizing radiation (i.e., radiation capable of producing ion pairs) as generally employed
for medical imaging involves the following:
radiology
￿ Radiation that is introduced into the body, thereby making the patient the “source” of
radiation emissions, or
￿ Externally produced radiation, which passes through the patient and is detected by
radiation-sensitive devices “behind” the patient.
FIGURE 15.1
An early x-ray image, dated 1895.
Courtesy of http://graphics8.nytimes.com/images/2007/06/19/science/
19docs.1901.jpg.
Search WWH ::




Custom Search