R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

Future developments 277
slices to be taken. In addition, increasing computing power and more
sophisticated software are enabling ever-greater resolution and more
control over how the images are handled and displayed.
Cone beam CT shows a great deal of potential and could expand the
application of three-dimensional CT data and therefore increase the number
of sources available for medical modelling. Rather than using rotating collimated
X-ray beams and detectors, cone beam scanners use a cone shaped
beam of X-rays in conjunction with a single, but large, fl at detector to
enable the simultaneous capture of many slices of data. This greatly reduces
the complexity of the scanner making it a cheaper technology than existing
CT scanners. It also results in signifi cantly lower X-ray dosage for the
patient. Because they use one large detector, current cone beam scanners
are limited in the extent of anatomy that they can capture. Therefore, they
are being targeted at specifi c applications, such as dentistry. The advent of
this cheaper and more accessible technology will open up many opportunities
for computer-aided design, computer-aided surgical planning and
medical modelling.
Magnetic Resonance (MR) imaging has so far been used infrequently for
three-dimensional virtual and physical modelling, but the development of
more tissue specifi c protocols is enabling imaging of organs that has previously
been diffi cult to achieve using CT. It is likely that the use of MR for
many types of imaging requirement will increase as the speed and sophistication
of the scanners improves. As with CT, the development of more
sensitive detectors and the use of multiple arrays of detectors will improve
speed and resolution. More sophisticated software will be able to better
fi lter out noise and produce sharper, clearer images.
The benefi t of using non-ionising radiation will lead to a greater demand
for MR compared to CT for some clinical situations that cannot justify the
exposure to X-rays. This is likely to lead to a growing application of modelling
from MR. The growing interest in modelling soft tissues is also likely
to encourage more work with MR data.
Different types of scanner are also likely to show potential in threedimensional
modelling. Positron emission tomography, for example, shows
the potential for scanning devices to be pathology targeted rather than
anatomy targeted. Such modelling projects may enable better treatment
planning or enable computer-aided, computer guided or even robotic
surgery.
Improvements in three-dimensional ultrasound scanning may lead to the
ability to model from the data, which has until now tended to show too
much noise to be of practical use in modelling. However, some modelling
work has been done, and the ease of use, compact size and relative safety
of ultrasound will encourage the exploitation of the data it can provide in
modelling.