Adaptive Imaging Versus Periodic Surveillance for Intrafraction Motion Management During Prostate Cancer...

Area of Science:

• Radiation Oncology
• Medical Imaging
• Prostate Cancer Treatment

Background:

• Prostate cancer radiotherapy requires precise tumor targeting.
• Intrafraction motion can compromise treatment accuracy.
• Current periodic imaging surveillance has limitations in managing motion during treatment.

Purpose of the Study:

• To compare the efficacy of adaptive imaging with automatic correction against periodic surveillance strategies.
• To evaluate the benefits of real-time motion management in prostate cancer radiotherapy.

Main Methods:

• Simulated intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) using Calypso data from 54 prostate cancer patients.
• Compared periodic imaging (manual/automatic correction) with continuous adaptive imaging using cine-MV and MV-kV imaging.
• Assessed couch shift delays and estimated 3D displacement for motion compensation.

Main Results:

• Without intervention, prostates moved out of a 3-mm margin ~20% of beam-on time.
• Adaptive imaging significantly reduced mean out-of-margin time to 0.6% (max 2.7%) with minimal imaging dose.
• Periodic imaging, even with reduced delays and automatic correction, left significant residual motion (up to 12.6%).

Conclusions:

• Continuous adaptive imaging with automatic motion compensation is more effective than periodic surveillance.
• Adaptive imaging provides superior intrafraction motion management in prostate cancer radiotherapy.
• This approach achieves better accuracy at a similar or lower imaging dose.