Biomedical Engineering Reference
In-Depth Information
static magnetic field of MRI, generated propulsion force, and RF magnetic field of
MRI produced power for the coils. The numerical model predicted that a 10
mm
tail could produce a speed of 7.9 mm/s force up to 5.5
mN
in a 3T static magnetic
field.
P. Va l d a s t r i
et al.
(2008) assessed the feasibility of using a swallowable wireless
capsule to deploy a surgical clip under remote control. The 12.8
mm
33.5
mm
capsule equipped with four permanent magnets was steered by means of the
external magnetic guidance to a specific target successfully in an in vivo surgical
experiment. This study paves a way to a new generation of capsule device able to
perform both diagnostic and therapeutic tasks.
In all, the external magnetic actuation is capable of both propulsion and
orientation of the capsule. It saves internal energy of the capsule compared with
mechatronic mechanisms, which makes it possible to achieve wireless control. The
deficiency is that the external system is usually quite complex and bulky, like the
magnetic field generator of MRI. There is a trade-off between the internal and
external power consumptions. One possible solution of the problem may be to
combine the advantage of the two approaches by designing an internal locomotion
mechanism which can interact with external magnetic system for part of control
(Wang
et al.
2007).
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13.4 CONCLUSION AND FUTURE PROSPECT
Capsule endoscopy has opened up a new world of diagnostic and other possibil-
ities for the gastroenterologist. It is remarkable to see images of small intestinal
abnormalities in the small intestine, which was not possible until recently when
development of wireless capsule endoscopy enabled a much less invasive and
more complete examination of the small intestine.
In the future, the capsule endoscopy is likely to have a substantial impact on
the management of small intestinal disease as well as other parts of the GI tract
after it evolves from passive to active, i.e., it can make autonomous movement in
the GI tract. Currently, the progress is hindered by power and size limitations
inside the swallowable capsule since the device may require more power for
movement, altering the view, spraying medicine, activating a biopsy and other
features, and more space to embody the equipments.
Some attempts are being or to be considered to generate power within living
body. These may include transcutaneous induction system, biologic batteries,
rechargeable batteries, motion energy, wireless power transmission Wang
et al.
(2007) and etc. In respect of the size limitation, a possible solution may be
combination of multiple robotic capsules. The tiny capsule robotic components
are ingested and assembled by themselves to configure in the GI tract to perform
precise interventions (Menciassi 2008, Harada 2009).
The invention of the capsule endoscope reminds people of the science fic-
tion movie The Fantastic Voyage, which was considered a mere figment of the
