Calling on many technologies, medical imaging like the camera control units is increasingly used to diagnose many diseases in addition to a clinical examination and other investigations, such as physical examinations or neuropsychological tests.

Medical imaging is also an essential element in clinical research, the study of diseases, and new treatments. There are many complementary imaging techniques. Imaging covers a wide variety of technologies developed thanks to the exploitation of the great discoveries of physics of the 20th century:

• Radio waves and x-rays
• The radioactivity of certain elements
• Magnetic fields.

The objective is to diagnose diseases, follow their evolution, discover how they work, and treat them better. Techniques are being developed to locate foci of infection, target them and activate the active ingredients of drugs only where desired. Or to destroy the well-localized cells thanks to shear waves emitted by an ultrasound machine, and therefore without surgery. The development of MRI for research on the brain also opens up the prospects for an increasingly detailed understanding of this very complex organ.

The Different Medical Imaging Technologies

The X-ray is based on X-rays that can cross more or less essential tissues according to their density. Thus, an X-ray emitting source is placed in front of the body to be radiographed, and a detector is placed at the rear of the body. The emitted photons will pass through the body, being more or less absorbed by the tissues encountered on their way. This makes it possible to differentiate the bones from the muscles on the final image.

Magnetic Resonance Imaging

Magnetic resonance imaging is based on the magnetic properties of water molecules that make up more than 80% of the human body. Water molecules, more precisely their hydrogen atoms, have a “magnetic moment,” or spin, which acts like a magnet. The MRI device consists of creating a powerful magnetic field (B0) using a coil.

The patient is placed in the center of this magnetic field, and all the water molecules present in the body will orient themselves according to B0. An antenna placed on the part of the body studied (here, the head) will make it possible to transmit and receive specific frequencies. On emission, the induced frequency will cause the molecules to switch in a plane perpendicular to B0.

When the antenna stops transmitting, the molecules return to their original position, transmitting a frequency picked up by the antenna. This is then processed as an electrical signal and analyzed by software. The signal differs depending on whether the tissues observed contain more or less water.