MRI quality control for low-field MR-IGRT systems: Lessons learned.

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Diagnostic Imaging

Background:

• Low-field magnetic resonance imaging (MRI) systems are increasingly integrated with radiation therapy delivery.
• Ensuring the quality and reliability of these integrated MRI-guided radiation therapy (MR-IGRT) systems is crucial for safe and effective patient treatment.

Purpose of the Study:

• To detail the lessons learned from quality control (QC) testing of low-field MR-IGRT systems.
• To identify common performance issues and their resolutions in MRI-⁶⁰Co and MRI-Linac systems.

Main Methods:

• Established MRI QC programs for low-field MRI-⁶⁰Co and MRI-Linac systems.
• Conducted a retrospective analysis of MRI subsystem performance across commissioning, operations, and maintenance.
• Classified performance issues into image noise/artifacts, magnetic field homogeneity/linearity, and system reliability/stability.

Main Results:

• Image noise and artifacts stemmed from room noise, cabling, and faulty RF coils.
• Gantry angle-dependent magnetic field inhomogeneities were noted, particularly in MRI-Linac systems.
• System interruptions were often caused by software disconnects due to hardware faults (e.g., patient table, gantry, MLC).

Conclusions:

• Significant technological challenges exist in implementing and maintaining MR-IGRT systems.
• Proactive identification and resolution of performance issues during commissioning are essential.
• Ongoing QC is vital for sustained operational integrity.