Computer simulation of selective excitation in n.m.r. imaging

It is attractive to apply selective excitation as part of a method for proton spin imaging of large objects. In the past, there has been some discussion on how selective excitation should be performed. The spin magnetization reacts in a nonlinear way to an r.f. (radio frequency) excitation pulse. This makes it difficult to give algebraic expressions for the excited transverse magnetization if one does not apply just a simpel rectangular r.f. pulse but, instead, an arbitrarily tailored pulse. We have, therefore, studied numerical solutions of the equations of motion (Bloch equations) for various forms of tailored pulses. Typical computation results will be shown and a brief discussion on practical aspects will be given.