NT Mobile scanner travels fully ramped up
Philips Medical Systems hopes to inject some life into the mobile
MRI industry by releasing a transportable version of its 1.5-tesla
Gyroscan ACS-NT scanner. The magnet is unique among 1.5-tesla
systems in that it is capable of traveling at field, reducing
set-up time to a matter of minutes.
Philips, of Shelton, CT, sent a 1.5-tesla NT Mobile on tour
last month to showcase its capabilities. The scanner logged some
7400 miles on a tour that lasted six weeks, and traveled fully
ramped up the entire time, according to Joe Nagle, product manager
for mobile MRI.
The development of mobile 1.5-tesla MRI has been hampered because
the magnetic fields of previous 1.5-tesla mobile scanners must
be ramped down while traveling. This avoids interference with
moving metal objects in the environment, which can disrupt the
homogeneity of the scanner's magnetic field. It then takes several
hours to ramp up the magnet once it has reached its destination.
In 1993 Philips debuted the NT scanners, which were notable
for their compact size and light weight (SCAN 12/29/93). Intermagnetics
General supplied Philips with the compact magnets, but Philips
also developed technology for the line that provides a means of
primary field compensation, ensuring that the homogeneity of the
magnet stays constant even if there are moving metal objects nearby.
The technology makes siting the NT scanners easier in stationary
settings but provides even greater advantages for mobile MRI.
"The system is much less sensitive to moving ferric objects,
such as automobiles and trucks," Nagle said. "It's not
as sensitive as previous magnets have been."
NT Mobile is identical to a standard 1.5-tesla NT and can perform
all the sequences the stationary magnet is capable of, including
1024 x 1024 imaging, echo-planar imaging and GRASE. The only application
it does not support is spectroscopy, due primarily to logistical
issues such as reimbursement.
Philips decided to put NT Mobile on tour to dispel doubts about
1.5-tesla mobile imaging. Past efforts have had disappointing
results, according to Chris Farr, director of marketing for MRI.
"In the past one of the big companies had a 1.5-tesla
mobile. It was a disaster," Farr said. "What we wanted
to show was not only that this machine was truly mobile, but that
there was no compromise on capabilities or performance."
On NT Mobile's summer tour, Philips employed a truck manufactured
by Calumet Coach of Calumet City, IL. The system can also be configured
in mobile vans manufactured by Ellis and Watts of Batavia, OH.
Additional shielding in the magnet's trailer confines the magnet's
five-gauss line entirely within the trailer walls.
Philips also placed a 3M DryView 8700 dry laser printer in
the mobile van. The printer obviated the need to have film sent
outside the van for developing, making mobile imaging even more
Philips believes NT Mobile will help revive the mobile imaging
segment, which has experienced a shakeout in recent years as many
smaller hospitals once on mobile routes acquire their own scanners.
Many of these hospitals have acquired mid-field magnets to avoid
the cost of 1.5-tesla systems, but still have a need for high-field
"What has happened in MRI is that a 0.5-tesla machine
can be afforded by even quite small community hospitals,"
Farr said. "This 1.5-telsa scanner is bringing a level of
technology to these hospitals that there is absolutely no way
they could afford on their own."
Philips is in discussions with mobile firms, many of whom need
to replace older mid-field MRI scanners in their fleets and would
welcome the opportunity to offer 1.5-tesla scanning. The company
believes it will ship as many as 10 NT Mobiles by the end of the
Other potential customers include large hospital chains that
have purchased smaller suburban hospitals and would rather set
up a mobile route between the smaller hospitals than install a
new 1.5-tesla scanner in each facility, Farr said.
"What this provides them with is the ability to take the
same kind of technology as they have at their home base and offer
it as an outreach service," Farr said.