The def
inition of
imaging is the visual representation of an object. Medical
imaging began after the discovery of x-rays by Konrad Roentgen 1896. The first fifty years of radiological
imaging, pictures have been created by focus
ing x-rays on the exam
ined body part
and direct depiction onto a s
ingle piece of film
inside a special cassette. The next development
involved the use of fluorescent screens
and special glasses to see x-ray images
in real time.
A major development was the application of
contrast agents for a better image
contrast and organ visualization.
In the 1950s, first nuclear medic
ine studies showed the up-take of very low-level radioactive chemicals
in organs, us
ing special gamma cameras. This medical
imaging technology allows
information of biologic processes
in vivo. Today, PET
and SPECT play an important role
in both cl
inical research
and diagnosis of biochemical
and physiologic processes.
In 1955, the first x-ray image
intensifier allowed the pick up
and display of x-ray movies.
In the 1960s, the pr
incipals of sonar were applied to diagnostic
imaging.
Ultrasonic waves generated by a quartz crystal are reflected at the
interfaces between different tissues, received by the
ultrasound machine,
and turned
into pictures with the use of computers
and reconstruction software.
Ultrasound imaging is an important diagnostic tool,
and there are great opportunities for its further development. Look
ing
into the
future, the gr
and challenges
include
targeted contrast agents, real-time
3D ultrasound imaging,
and molecular imaging.
Digital imaging techniques were implemented
in the 1970s
into conventional fluoroscopic image
intensifier
and by Godfrey Hounsfield with the first computed tomography.
Digital images are electronic snapshots sampled
and mapped as a grid of dots or pixels. The
introduction of x-ray CT revolutionised medical
imaging with cross sectional images of the human body
and high
contrast between different types of soft tissue. These developments were made possible by
analog to
digital converters
and computers. The multislice
spiral CT technology has exp
ands the cl
inical applications dramatically.
The first
MRI devices were tested on cl
inical patients
in 1980. The spread of CT mach
ines is the spur to the rapid development of
MRI imaging and the
introduction of
tomographic imaging techniques
into diagnostic nuclear medic
ine. With technological improvements
includ
ing higher
field strength, more
open MRI magnets, faster
gradient systems,
and novel data-acquisition techniques,
MRI is a real-time
interactive
imaging modality that provides both detailed structural
and functional
information of the body.
Today,
imaging in medic
ine has advanced to a stage that was
inconceivable 100 years ago, with grow
ing medical
imaging modalities:
•
Single photon emission computed tomography (SPECT)
•
Positron emission tomography (PET)
All this type of scans are an
integral part of modern healthcare.
Because of the rapid development of
digital imaging modalities, the
increas
ing need for an efficient management leads to the widen
ing of
radiology information systems (RIS)
and archival of images
in digital form
in picture archiving and communication systems (PACS).
In telemedic
ine, healthcare professionals are l
inked over a
computer network. Us
ing cutt
ing-edge comput
ing
and communications technologies,
in videoconferences, where audio
and visual images are transmitted
in real time, medical images of
MRI scans, x-ray exam
inations, CT scans
and other pictures are shareable.
See also
Hybrid Imaging.
See also the related poll results: '
In 2010 your scanner will probably work with a field strength of', '
MRI will have replaced 50% of x-ray exams by'
•
] and 2 definitions [
], (+ 1 Boolean[
] results
Further Reading:
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