Patients who get anxious in enclosed hospital equipment can stop worrying.
Siemens claims it has the answer with the launch of an 鈥榦pen layout鈥� magnetic
resonance imaging scanner for 鈥榮eeing鈥� inside the human body.
MRI machines have found increasing use in hospitals over the past decade
because, unlike X-ray scanners, they are thought to cause no harm to tissue.
But according to Siemens, one drawback of MRI is the layout of the machines.
Patients have to lie inside a cylindrical chamber up to 2 metres long.
This, says Siemens, intimidates at least five per cent of patients, especially
children, and makes it awkward for doctors and nurses to reach the patient
during the scan.
Siemens has launched a machine this week which has the cross section
of a letter 鈥楥鈥� instead of the usual 鈥極鈥�. Its shape resembles that of an
open carpentry vice on its side. The patient is slid into the jaws of the
鈥楥鈥�, which are permanently open.
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To reshape the device, Siemens had to change the magnetic field on which
the scans depend. Normally, the magnetic field generated runs along the
cylinder, which is essentially a huge electric coil. Electricity passing
through the coil generates the magnetic field with a pole at either end
of the cylinder.
To make the open version, Siemens used two coils of wire, one below
and one above the patient, explains Andy Hind, the general manager of cross-sectional
imaging at Siemens. 鈥楾he field is generated between these two poles, so
the field is vertical going from the back to the front of the patient instead
of along the patient.鈥�
The magnetic field generated by the magnet is 0.2 tesla, some 4000 times
larger than the Earth鈥檚 magnetic field. Siemens is to launch the scanner
commercially in the US and Britain next spring.
