Related Experiment Video
Updated: Mar 2, 2026
08:17
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
16.3K
SU-D-BRA-06: Investigation of Prostate Intrafractional Motion during External Beam Radiotherapy for a Large Patient
Medical Physics
|May 19, 2017
Summary
Prostate intrafractional motion during radiotherapy is often within 3mm, but some patients experience larger shifts requiring real-time adjustments. Completing treatments within 5 minutes may reduce prostate movement during radiotherapy.
Area of Science:
- Radiation Oncology
- Medical Physics
- Prostate Cancer Treatment
Background:
- Prostate intrafractional motion can impact the accuracy of external beam radiotherapy.
- Understanding and quantifying this motion is crucial for optimizing treatment delivery.
Purpose of the Study:
- To analyze prostate intrafractional motion during external beam radiotherapy.
- To provide guidance for advanced intensity-modulated radiation therapy (IMRT) for prostate cancer.
Main Methods:
- Utilized the Calypso 4D-localization system to track prostate intrafractional motion during IMRT and RapidARC treatments.
- Analyzed data from 8600 treatment fractions across 230 prostate cancer patients.
- Assessed prostate movements exceeding thresholds (2, 3, 5, 7mm) over various durations and treatment times.
Main Results:
- 66.2% of fractions showed prostate shifts >2mm for >10 seconds; 34.9% showed shifts >3mm.
- Patients with the largest motion experienced shifts >3mm in 76.0% of fractions for >10 seconds.
- Posterior-direction motion was significantly higher; motion increased after the initial setup and was lower in treatments completed within 5 minutes.
Conclusions:
- Prostate intrafractional motion is generally within 3mm but can exceed this for certain patients.
- Real-time motion correction or larger treatment margins may be necessary for some patients.
- Completing radiotherapy treatments within 5 minutes appears beneficial for minimizing prostate motion.
