A radiation-transparent, rotatable receive-only extremity RF coil for flexible MR-guided particle therapy at 0.25 T

Motivation: MR-guided particle therapy (MRgPT) could improve tumor control and reduce healthy tissue dose, thereby increasing quality of therapy compared to conventional CT-guided radiotherapy. Goal(s): Development of a rotatable, radiation-transparent extremity radiofrequency (RF) coil suitable for MRgPT at a 0.25T C-shaped magnet. Approach: The receive field homogeneity of the RF coil was evaluated for different rotation angles in electromagnetic field simulations, and the SNR was investigated in a homogeneous phantom in comparison to two commercial coils. Results: The constructed extremity RF coil including a custom-built preamplifier achieves improved receive field homogeneity and SNR compared to two commercial RF coils and is compatible with MRgPT. Impact: The rotatable, radiation-transparent RF coil enables MRgPT with through-coil irradiation and multi-angle access to the patient. The developed RF coil and preamplifier design provides better RF field homogeneity and SNR over a larger FOV compared to two commercial RF coils.