Magnetic field of resonance can attract metallic objects, such as weapons, and cause accidents; understand

Magnetic resonance imaging is an imaging exam that allows the visualization of various structures of the human body in detail, enabling the diagnosis of different diseases.

The widely used device has a large magnet, which is capable of generating a magnetic field stronger than that of Earth, capable of influencing the movement of water molecules in the organism, generating high quality images.

The death in São Paulo of lawyer Leandro Mathias, after accidentally firing his own gun during the MRI, drew attention to the safety protocols for carrying out the exam. The magnetic field generated by the device pulled the gun from the lawyer’s waist and triggered the shot.

The Brazilian College of Radiology and Image Diagnosis (CBR) states that Is the MRI scan safe? provided that due care is taken prior to its implementation.

“The MRI machine is like a big magnet. It works like an electromagnetic field, to align the molecules of the human body. When you make this movement, it ends up generating a signal and then this signal is transformed into an image”, explains doctor Cesar Higa Nomura, superintendent of diagnostic medicine at Hospital Sírio-Libanês, in São Paulo.

The specialist points out that the performance of magnetic resonance has several points that need attention, with regard to the safety of operators, patients and companions.

security protocol

All patients who will undergo magnetic resonance imaging must, obligatorily, answer a questionnaire, which addresses questions about the presence of fixed or mobile metallic material in the body, including prostheses, pacemakers and piercings, for example.

Tattoos, which are rich in iron components, also deserve attention, as they may contain dye components capable of absorbing the heat generated during the examination, which can cause local burns.

The professionals who carry out the exam must guide the patients regarding the removal of non-compatible metallic materials. In addition, patients should be informed of the reason for prohibiting the possession or use of the materials due to the strength of the magnetic field.

According to the Brazilian College of Radiology and Image Diagnosis (CBR), patients who have metallic or electronic devices, such as non-compatible pacemakers, old cerebral aneurysm clips and external orthopedic fixators, cannot undergo the exam.

The CBR points out that companions must also, obligatorily, respond to the same questionnaires as the services, follow the guidelines of employees and respect the entire safety protocol.

The doctor at Hospital Sírio-Libanês explains that the safety protocol includes signs in the sectors, safety warnings and the prohibition of non-compatible material in the exam room.

“As the MRI scan has a huge electromagnetic field, the entire nearby area is separated by levels. It is prohibited to circulate with metallic material in the area, and it is absolutely forbidden to enter with any type of metallic material in the device”, says Nomura.

The expert claims that the strength of the electromagnetic field is capable of attracting various objects, such as small hairpins and rings to heavier materials, such as chairs, beds and floor polishers.

“In the vast majority of services, patients exchange their clothes for an apron, precisely because people forget that they have a coin in their pocket, a chain around their neck, a bracelet or a ring. That’s why this area is always very careful”, he says. “All people who work with radiology and MRI know that you have to be very careful in preparing the patient. Fortunately, it is very rare for accidents to happen ”, she adds.

Units and laboratories may offer lockers or specific places for personal objects to be stored during the exam.