Parametric Relations in Multicoil Cylindrical MRI Magnet Design

Abstract

In MRI magnet design, optimized configurations are generated by different manufacturers, which are driven by the pursuit of competitive cost and performance. It is the magnet envelope and the field constraints such as homogeneity and stray field that largely define the coil topology. Understanding the scaling laws and relations that govern sensitivities in the design space gives a designer a tool for scoping and tradeoff analyses, guiding his selection of design options. A study is presented that produces scaling relations and characterizes the amount of conductor, the number and location of coils as a function of the magnet envelope, and field requirements. Described is the birth of coils and their movement with an expanding field of view, as well as impacts of shielding and of shorter envelopes. Derived relations are given in parametric form, which is described by dimensionless complexes.