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Planning CT Identifies Patients at Risk of High Prostate Intrafraction Motion
Hendrik Ballhausen1, Minglun Li1, Elia Lombardo1
1Department of Radiation Oncology, LMU University Hospital, LMU Munich, 81377 Munich, Germany.
Cancers
|August 26, 2023
Summary
Pelvic dimensions from planning CT scans can predict prostate intrafraction motion during radiation therapy. A lesser pelvis diameter over 106 mm indicates a higher risk of significant prostate movement.
Area of Science:
- Medical Physics
- Radiation Oncology
- Radiotherapy Imaging
Background:
- Prostate motion during radiation therapy can lead to inaccuracies in dose delivery.
- Predicting intrafraction motion is crucial for optimizing treatment planning and patient outcomes.
Purpose of the Study:
- To investigate the correlation between lesser pelvis dimensions and prostate intrafraction motion.
- To identify a predictive marker for high prostate motion using planning CT scans.
Main Methods:
- Analysis of 4D ultrasound data from 1791 radiation therapy fractions in 100 patients.
- Measurement of prostate motion (standard deviation, range of motion, diffusion coefficient).
- Determination of inner lesser pelvis diameter from planning CT scans.
Main Results:
- Prostate motion significantly increases with larger inner lesser pelvis diameters (p < 0.005).
- A diameter >106 mm predicts high prostate intrafraction motion with high sensitivity and negative predictive value.
- Area under the receiver operator curve (AUROC) ranged from 62% to 80% across different axes.
Conclusions:
- Inner lesser pelvis diameter is a valuable predictor of prostate intrafraction motion.
- This simple metric from planning CT can help identify patients at risk for significant prostate movement.
- Facilitates personalized treatment strategies in prostate radiotherapy.
