MRI-based radiotherapy planning method using rigid image registration technique combined with outer body correction...

Area of Science:

• Medical Physics
• Radiotherapy Technology
• Medical Imaging

Background:

• Magnetic Resonance Imaging (MRI) is crucial for radiotherapy planning due to superior soft-tissue contrast.
• Computed Tomography (CT) scans are the gold standard for electron density information required for accurate dose calculation.
• Generating accurate pseudo CT from MRI data is essential for MRI-only radiotherapy workflows.

Purpose of the Study:

• To investigate an alternative method for generating pseudo CT images from MRI data for radiotherapy planning.
• To refine pseudo CT generation using rigid image registration and outer body correction.
• To assess the feasibility and accuracy of the proposed pseudo CT method for brain radiotherapy.

Main Methods:

• Pseudo CT generation involved rigid image registration between planning MRI and diagnostic CT.
• Outer body correction was applied to refine the pseudo CT morphology to match the planning MRI.
• The method was applied to brain image data, and dosimetry was compared to CT-based calculations.

Main Results:

• The pseudo CT method demonstrated high accuracy, with pixel doses agreeing well with actual CT.
• Dosimetric agreement was within 2%, and geometric uncertainty was within 1mm.
• Validation confirmed the method's reliability for MRI-based radiotherapy planning.

Conclusions:

• The developed pseudo CT generation method is accurate and reliable for MRI-based radiotherapy planning.
• This technique offers a viable alternative to traditional CT-based planning, particularly for brain treatments.
• The study supports the potential for MRI-only radiotherapy workflows, reducing reliance on CT scans.