SQUID magnetometers can be used in conjunction with MRI machines to transpose magnetic field signals into specific areas of the brain.
A superconducting quantum interference device (SQUID) magnetometer is an instrument for detecting and measuring the magnetic fields generated by electric current. The magnetometer converts the magnetic fluctuations back into an electronic signal and relays the signal to a monitoring device that produces a topographical map of the magnetic impulses. The sensitivity of a SQUID magnetometer allows it to be used as a medical diagnostic tool.
Magnetoencephalography can measure activity in millimeter areas of the brain.
The SQUID magnetometer usually consists of a highly conductive coil connected to the sensor and probe. In medical applications, these components are typically contained in a cryogenic chamber called a Dewar. The apparatus is cooled by liquid helium or nitrogen. The temperature in this chamber can be as low as -459 degrees Fahrenheit (-273 degrees Celsius). The probe exits the chamber and connects to a flow loop, which transfers the signal to a monitor.
Obstetricians use magnetocardiography to assess fetal heart conditions.
Magnetoencephalography uses SQUID magnetometers to map the function of neurons. A device specially designed for encephalography resembles a helmet containing 300 encapsulated sensors. In addition to putting the helmet on while the patient is seated, technicians often apply various skin sensors that indicate the position of the head. Patients may also be asked to lie on a table with their head encapsulated by the helmet.
This non-invasive form of diagnostic medicine can measure activity in millimeter or larger areas of the brain. SQUID magnetometers generally capture magnetic signals in mere milliseconds, producing a high resolution image represented as spikes. Neurologists use SQUID magnetometers to diagnose epilepsy or Alzheimer’s. When used in conjunction with a magnetic resonance imaging (MRI) machine, doctors can transpose magnetic field signals into specific areas of the brain.
Doctors can assess heart muscle depolarization and repolarization using magnetocardiography. The SQUID magnetometer used for cardiology resembles a large moving cylinder containing sensors. Technicians position the device over the patient, like a portable X-ray machine. By measuring the magnetic fields produced by the electrical signals emitted by the heart, cardiologists can diagnose and treat life-threatening arrhythmias. Doctors can implement this method of cardiography in a catheter lab.
The biomedical applications of a SQUID magnetometer include many areas of the body. Obstetricians use magnetocardiography to assess fetal heart conditions. This highly sophisticated technology also aids clinicians in diagnosing gastroenterological disorders. Equipment is normally contained in a shielded room that prevents interference from electronic devices or other sources of magnetic fields.