Shimming improves the uniformity of an MRI system’s main magnetic field, known as B0—the static field used for imaging. Field homogeneity matters because variations can contribute to artifacts, distortion, and inconsistent fat suppression. The required adjustment depends on the magnet, its environment, and the examination.

Passive and Active Shimming Serve Different Roles

Passive shimming uses carefully positioned pieces of magnetic material such as iron to correct field variations. Magnet service may also involve adjusting superconducting shim circuits on systems designed for that method. These are model-specific engineering tasks, guided by field measurements and manufacturer procedures—not interchangeable options chosen solely by service cost or helium coverage.

During scanning, active shim coils can provide additional corrections for the patient and imaging volume. These examination-specific adjustments should not be confused with installation or service work on the magnet’s superconducting shim circuits.

Measurements Come Before Adjustments

A qualified service team evaluates field homogeneity and compares the results with the applicable system requirements. Magnet design, room conditions, and the approved service method determine the appropriate correction. A shimming tool alone does not guarantee image quality, and persistent artifacts can have causes beyond field homogeneity.

Where the MPS2 Fits

The MPS2 Universal Ramp Shim Power Supply supports active shimming on compatible GE LCC magnets. Its ramping and shim functions serve different tasks; compatibility, connections, and the correct procedure must be confirmed for the specific system before use.

Contact Digit Systems to discuss the magnet and service tools required for your project.

Further reading: Siemens Healthineers: Management of Field Uniformity. This overview is not a substitute for manufacturer service instructions.

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