Medical diagnosis equipment is an important part of the medical system, and its core requirement is to obtain accurate and detailed information about the human body. Strong magnets, with their excellent magnetic properties, have been widely used in various medical diagnosis equipment, greatly improving the accuracy and efficiency of diagnosis. Among them, magnetic resonance imaging (MRI) equipment is the most typical application scenario of strong magnets, and in addition, it is also applied in nuclear magnetic resonance spectroscopy (MRS) equipment, magnetic particle imaging (MPI) equipment and other emerging diagnosis equipment.

In MRI equipment, strong magnets are the core components that generate the main magnetic field. The main magnetic field is the basis for aligning the hydrogen nuclei in the human body. Only under the action of a strong and uniform main magnetic field can the hydrogen nuclei resonate under the excitation of radio frequency pulses, and then generate nuclear magnetic resonance signals that can be detected. At present, the main magnetic fields of clinical MRI equipment are mostly 1.5T and 3.0T (T is the unit of magnetic induction intensity), and high-field MRI equipment with 7.0T or higher has been gradually applied in scientific research and clinical trials. The strong magnetic field of high-field MRI can significantly improve the signal-to-noise ratio of the image, making the image clearer and more detailed, which is conducive to the early detection of small lesions and the accurate diagnosis of complex diseases (such as early tumors, neurodegenerative diseases, etc.).

The strong magnets used in MRI equipment are mainly divided into two types: superconducting magnets and permanent magnets. Superconducting magnets use superconducting materials (such as niobium-titanium alloy) that can achieve zero resistance at extremely low temperatures (usually liquid helium temperature, -269.15°C). They can generate a very strong and uniform magnetic field, which is the first choice for high-field MRI equipment. However, superconducting magnets have high requirements for the cooling system, and the operation and maintenance costs are relatively high. Permanent magnets, on the other hand, use rare-earth permanent magnet materials (such as neodymium-iron-boron) to generate a constant magnetic field. They do not require a complex cooling system, have low energy consumption and maintenance costs, and are mostly used in low-field and medium-field MRI equipment (such as 0.35T, 0.5T). With the continuous improvement of the performance of permanent magnet materials, the magnetic field intensity and uniformity of permanent magnet MRI equipment are also constantly improving, and they are widely used in primary hospitals and community health service centers due to their cost advantages.

In addition to MRI equipment, strong magnets also play an important role in magnetic particle imaging (MPI) equipment, a new type of medical imaging technology. MPI is a non-invasive imaging technology that uses the magnetic response of superparamagnetic iron oxide nanoparticles (SPIONs) to generate images. The strong magnets in MPI equipment generate a gradient magnetic field with a "zero magnetic field point". When the SPIONs injected into the human body pass through the zero magnetic field point, their magnetization intensity changes sharply, generating a detectable signal. The strong magnetic field can enhance the magnetic response of SPIONs, improve the signal intensity and spatial resolution of the image. Compared with MRI, MPI has the advantages of fast imaging speed, high sensitivity and no radiation, and is expected to play an important role in the fields of vascular imaging, tumor targeting imaging and cell tracking.

Nuclear magnetic resonance spectroscopy (MRS) equipment is another important application scenario of strong magnets. MRS is a technology that uses nuclear magnetic resonance phenomena to analyze the chemical composition and metabolic changes of tissues and organs. The strong magnetic field can improve the resolution of the spectrum, making it possible to distinguish more chemical components. This is of great significance for the early diagnosis of diseases such as brain tumors, liver diseases and muscle diseases. For example, in the diagnosis of brain tumors, MRS can detect changes in the content of metabolites such as choline, creatine and N-acetylaspartate in brain tissue, helping doctors distinguish between benign and malignant tumors and formulate treatment plans.

The application of strong magnets in medical diagnosis equipment not only improves the level of diagnosis, but also expands the scope of diagnosis. With the continuous development of magnetic materials and imaging technology, the performance of strong magnets will be further optimized, and the medical diagnosis equipment based on strong magnets will become more accurate, efficient and portable, bringing new opportunities for the development of precision medicine.