Intrafractional motion management in external beam radiotherapy.

Area of Science:

• Radiation oncology
• Medical physics
• Image-guided therapy

Background:

• Modern radiotherapy demands high precision for conformal dose delivery, particularly with high-dose-per-fraction techniques like stereotactic body radiotherapy.
• Patient instability, motion (respiratory, random), tumor deformation, and baseline shifts pose significant challenges to treatment accuracy.
• Intrafractional motion, especially respiratory motion in chest and abdominal radiotherapy, necessitates effective management strategies.

Purpose of the Study:

• To review current intrafractional motion management strategies in radiotherapy.
• To discuss the advantages and limitations of various motion control techniques.
• To explore future advancements in real-time tumor tracking and motion management.

Main Methods:

• Review of existing literature on intrafractional motion management in radiotherapy.
• Discussion of techniques including respiratory motion integration, breath-hold, abdominal compression, gating, and real-time tracking.
• Exploration of emerging technologies like MRI-linear accelerators for soft tissue monitoring.

Main Results:

• Several intrafractional motion management strategies have been developed to improve treatment precision.
• Successful motion management reduces planning target margins and ensures accurate dose delivery.
• MRI-linear accelerators offer potential for radiation-free real-time soft tissue monitoring.

Conclusions:

• Effective intrafractional motion management is essential for precise radiotherapy, especially with advanced techniques.
• Various techniques exist, each with specific benefits and drawbacks.
• Real-time tracking, particularly MRI-based approaches, represents a promising future direction for motion management.