Three-row MRI receive array with remote circuitry to preserve radiation transparency.

Area of Science:

• Medical Physics
• Magnetic Resonance Imaging
• Radiation Oncology

Background:

• 1.5 T MR-linac coil arrays are typically limited to one or two rows.
• This limitation is due to the need to place radiation-opaque circuitry near the coils and within the linac beam path.
• Existing layouts can restrict parallel imaging capabilities.

Purpose of the Study:

• To design and construct a three-row coil array for MR-linac systems.
• To enable a central coil row by relocating circuitry away from the linac beam path.
• To maintain a radiolucent window for the linac beam while improving parallel imaging.

Main Methods:

• Developed a remote circuit strategy including phase shifters and standard RF components.
• Tested prototype single-channel coils with remote versus local circuitry.
• Compared the performance of two-row and three-row coil arrays.

Main Results:

• Single-channel coils with remote circuits maintained 85% SNR at depths ≥30 mm compared to local circuits.
• The three-row array achieved comparable SNR to the two-row array.
• The three-row array demonstrated improved geometry factors for head-foot parallel imaging acceleration.

Conclusions:

• Remote circuit placement allows for greater flexibility in MR-linac coil array design.
• This strategy can overcome limitations imposed by local circuitry.
• The developed approach supports enhanced parallel imaging acceleration in future MR-linac systems.