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Updated: Jul 7, 2026
06:08
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
A randomized comparison of interfraction and intrafraction prostate motion with and without abdominal compression
Tara Rosewall1, Peter Chung, Andrew Bayley
1Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ont., Canada. Tara.Rosewall@rmp.uhn.on.ca
Summary
Intrafraction prostate motion is a significant source of error in radiotherapy, even after interfraction corrections. Abdominal compression did not significantly reduce prostate motion in either immobilization system studied.
Area of Science:
- Radiation Oncology
- Medical Physics
Background:
- Prostate motion during radiotherapy can affect treatment accuracy.
- Standard immobilization devices and newer systems with compression aim to minimize this motion.
Purpose of the Study:
- To quantify and compare inter- and intrafraction prostate motion.
- To evaluate the efficacy of the BodyFix system with abdominal compression versus the VacLok system.
Main Methods:
- Thirty-two patients were randomized to VacLok or BodyFix immobilization.
- Interfraction prostate motion >3 mm was corrected pre-treatment.
- Prostate motion (inter- and intrafraction) was measured using electronic portal images.
Main Results:
- No significant difference in interfraction or intrafraction prostate motion was observed between the VacLok and BodyFix systems.
- Median intrafraction motion was slightly less than interfraction motion in AP and SI directions.
- The planning target volume (PTV) encompassed over 95% of the total prostate motion observed.
Conclusions:
- Intrafraction prostate motion is a primary source of error after interfraction correction in radiotherapy.
- The addition of abdominal compression did not significantly impact interfraction or intrafraction prostate motion.
