Methods of preparing and operating an MRI multi-channel coil

A method of operating a multi-channel transmit coil for at least one of magnetic resonance imaging or a medical treatment device, wherein the multi-channel coil comprises two or three coil rows being axially arranged adjacent to each other along a longitudinal direction, wherein each of two or three coil rows comprises a plurality of coil elements being arranged in a ring such that they are azimuthally distributed around the longitudinal direction, wherein the multi-channel transmit coil has been prepared by:

• electro-magnetic decoupling of the two or three coil rows relative to each other, and
• minimizing a reflected power individually of each of the coil rows,
• said method comprising the step of:
• exciting each coil element of the multi-channel transmit coil by radio-frequency power signals,
• wherein:
• an excitation phase shift is pairwise applied between first and second rows of the two coil rows or between first, second and third rows of the three coil rows, and
• the excitation phase shift being selected in a range from 70° to 120° between the first row and the second row of the two coil rows, or in a range from 70° to 120° between the first row and the second row and in a range from 20° to 80° between the second row and the third row of the three coil rows.