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Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Prostate bed motion during intensity-modulated radiotherapy treatment.
Tracy Klayton1, Robert Price, Mark K Buyyounouski
1Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
International Journal of Radiation Oncology, Biology, Physics
|February 15, 2012
Summary
Accurate prostate bed localization is crucial for post-prostatectomy radiation therapy. Implanted radiofrequency transponders revealed significant setup errors and target motion, necessitating real-time tracking to improve treatment accuracy and reduce toxicity.
Area of Science:
- Radiation Oncology
- Medical Physics
- Urologic Oncology
Background:
- Accurate setup and localization of the prostatic fossa are essential for effective conformal radiation therapy after prostatectomy.
- Prostate bed motion and setup variations can lead to under-treatment or excess normal tissue toxicity.
Purpose of the Study:
- To report on prostate bed localization and motion characteristics using implanted radiofrequency transponders.
- To evaluate the accuracy of target localization and real-time tracking during radiation therapy.
Main Methods:
- Utilized the Calypso four-dimensional localization system with three implanted radiofrequency transponders for daily target localization and real-time tracking.
- Reviewed localization and tracking data from 20 patients undergoing intensity-modulated radiation therapy for prostate bed targeting.
Main Results:
- Prostate bed displacement exceeded 5 mm in 9% (A-P) and 21% (S-I) of fractions.
- Real-time tracking limits were exceeded in 11% of fractions, with motion often directed towards the rectum.
- Fifteen percent of treatments were interrupted for repositioning, and 70% of patients required repositioning at least once.
Conclusions:
- Setup errors and prostatic fossa motion are significant challenges in post-prostatectomy radiotherapy.
- Implanted transponders and real-time tracking of the prostate bed can enhance the accuracy of radiation therapy plan delivery.
