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Published on: April 9, 2019
Robustness and precision of an automatic marker detection algorithm for online prostate daily targeting using a
S Aubin1, L Beaulieu, S Pouliot
1Centre Hospitalier Universitaire de Québec (L'Hôtel-Dieu) and Centre de Recherche en Cancérologie de l'Université Laval, 11 Côte du Palais, Quebec, QC, G1R 2J6, Canada.
Medical Physics
|August 9, 2003
Summary
An automated algorithm accurately detects prostate markers using electronic portal imaging, enabling precise daily radiotherapy adjustments. This method ensures accurate patient positioning, improving treatment efficacy and reducing organ motion errors.
Area of Science:
- Medical Physics
- Radiotherapy Technology
- Image Analysis
Background:
- Accurate daily patient positioning is crucial for effective radiotherapy.
- Organ motion can lead to significant setup deviations during treatment.
- Implanted markers offer a reliable method for tracking organ position.
Purpose of the Study:
- To evaluate an algorithm for daily prostate localization using implanted markers and a video-electronic portal imaging device (V-EPID).
- To determine the accuracy and consistency of automatic marker detection.
- To assess the potential for real-time setup correction in radiotherapy.
Main Methods:
- Implanted three gold markers in the prostate of seven patients.
- Acquired clinical images using a BeamViewPlus 2.1 V-EPID during radiotherapy.
- Developed and applied an algorithm based on marker attenuation and spatial distribution for detection.
- Analyzed 1182 clinical images acquired at various dose levels.
Main Results:
- The algorithm achieved an average detection efficiency of 93% for individual markers and 85% for marker groups.
- Detection and validation were completed within 0.20-0.40 seconds.
- Using the center of mass of markers, displacements were corrected within 1.0 mm in 84% of cases and 1.5 mm in 97% of cases.
- Excellent marker detection was achieved even at low dose levels.
Conclusions:
- The standard video-based EPID demonstrates excellent marker detection capability.
- The V-EPID, radiopaque markers, and automatic detection algorithm can successfully track and correct daily setup deviations.
- This technology holds promise for improving radiotherapy accuracy by compensating for organ motion.
