Magnetic resonance imaging, or MRI for short, is a state-of-the-art method used to capture images of different parts of the human body as needed. This method uses magnetic resonance or magnetic resonance between the hydrogen atoms in our body using magnetic fields and radio waves. In recognition of the development of this technology, the Nobel Prize has been awarded four times, including 2003, in medicine.
The earliest form of magnetic resonance imaging was nuclear magnetic resonance imaging, or NMRI. The main basis is the magnetic resonance of the nucleus. The smallest part of any object is the atom. The nucleus is at the center of the atom. Inside the nucleus are protons and neutrons. The nucleus is very small. Smaller than that are protons and neutrons.
The nuclear world is made up of the nucleus and its components. The protons and neutrons that inhabit the nucleus world have their own magnetic resonances — they rotate on their own axes in a magnetic field.
The magnetic resonance of protons
The magnetic resonance of protons was first discovered in 1947. Edward Mills, a professor at Felix Block at Stanford University and a professor at Harvard University, explained the magnetic resonance in the protons of the parcel nucleus. For this he was awarded the Nobel Prize in Physics in 1952. Over the next two decades, efforts were made to find ways to harness nuclear magnetic resonance.
Most of our body components are fat and water. Fat and water are again the sum of innumerable hydrogen atoms. Hydrogen atoms make up 83 percent of our body’s material. There are no neutrons in the nucleus of a hydrogen atom. As a result, the nucleus of a hydrogen atom is a proton. Protons have a positive electrical charge. As soon as they come in contact with any kind of magnetic field, these protons start vibrating and spin at a certain frequency.
The speed of rotation of protons depends on the strength of the magnetic field. If any other electromagnetic wave moves near this magnetic field for any reason, then the speed of rotation can increase many times even if the strength of the magnetic field remains constant.
If a radio wave of equal frequency or a radio wave moves close to this proton, then the frequency of the proton and the frequency of the radio wave combine to form a resonance. Radio waves can vibrate from one million to ten billion times per second. Wireless waves are not harmful to the body. However, higher frequency waves — such as X-rays, gamma rays, etc. ক্ষ are harmful to the body.
In a magnetic field, the vibrations of protons are measured by focusing on a specific part of the body. Resonance is then created by providing radio waves of similar energy. Now as soon as the radio waves are removed, the hydrogen atom or proton of the body returns to its own frequency. The time it takes to go from resonance to non-resonance or normal is called relaxation time. In 1981, Professor Raymond Demadian conducted a study on body tumors to show the difference between normal cell and tumor relaxation times. The beginning of magnetic resonance imaging in diagnosing the disease since then. Different types of tissues in the body have different relaxation times. Computer software creates images of different parts of the body from the information of the difference in relaxation time. The contrast of the MRI image is very high. As a result, even the slightest abnormality is seen in the cells or tissues.
In 1973, Professor Hounsfield introduced X-ray based computed tomography (CT). That same year, Paul Lotterbar, a professor of chemistry in the Department of Radiology at the University of New York, demonstrated the successful application of MRI. He showed the practical application of how easy it is to take a picture of a cell with the help of MRI.
Meanwhile, Peter Mansfield, a professor at the University of Nottingham in England, developed a practical method for quickly converting signals from MRI into images. Professor Lotterbar and Professor Mansfield received the 2003 Nobel Prize in Medicine for their research. Earlier, in 1991, Richard Ernst of Switzerland was awarded the Nobel Prize in Chemistry for nuclear magnetic resonance spectroscopy. In 2002, Koot Wirich of Switzerland was awarded the Nobel Prize in Chemistry for promoting magnetic resonance from two-dimensional to three-dimensional.
The term nuclear is no longer used before magnetic resonance imaging. There is no reason behind it other than our social fear of the word nuclear. Much of the destructive image of nuclear is the result of unscientific cheap political propaganda. But today the citizens of all developed countries are enjoying the benefits of nuclear technology. In today’s developed world, MRI is being used to treat millions of patients every year. MRI has been used in hospitals since the 1980s. More than sixty thousand MRI machines are now being used around the world.
MRI can be used for proper treatment of almost all the organs of the body. MRI is especially useful for detecting defects in the brain and spinal cord. Before any operation, with the help of MRI, one can proceed by knowing the detailed information inside the body by looking at three-dimensional pictures. Successful use of MRI has made brain surgery much easier now.
The magnetic field strength of modern MRI machines used in medicine is three Tesla or more, which is about sixty thousand times more than the magnetic field of the earth.
MRI machines do not use any radiation, so they are much safer than X-ray or CT machines. However, no magnetic material can be kept in the body during MRI.
Author: Teacher and Researcher, RMET, Melbourne, Australia