Related Experiment Video
Updated: Jun 7, 2026
07:34
Utilizing vmTracking to Improve the Accuracy of Multi-Animal Pose Estimation in Rodent Social Behavior Studies
Published on: November 7, 2025
Detailed analysis of latencies in image-based dynamic MLC tracking
Per Rugaard Poulsen1, Byungchul Cho, Amit Sawant
1Department of Radiation Oncology, Stanford University, Stanford, California 94305, USA. perpolse@rm.dk
Medical Physics
|October 23, 2010
Summary
This study developed a method to analyze latency in dynamic multileaf collimator (DMLC) tracking, identifying image file writing as the primary delay. This latency analysis is crucial for improving real-time accuracy in image-guided radiation therapy.
Area of Science:
- Medical Physics
- Radiation Oncology
- Image-Guided Therapy
Background:
- Image-based real-time dynamic multileaf collimator (DMLC) tracking accuracy is limited by latency, the delay between target motion and MLC response.
- Reducing latency is critical for enhancing the precision of DMLC tracking in radiation therapy.
Purpose of the Study:
- To develop and validate a method for detailed latency analysis in image-based DMLC tracking.
- To identify specific components contributing to latency during the tracking process.
Main Methods:
- A prototype DMLC tracking system on a linear accelerator tracked a phantom with a fiducial marker during sinusoidal motion.
- Real-time target localization used kV or MV X-ray images, with varying imaging intervals (150-1000 ms).
- Synchronization of image acquisition, marker segmentation, MLC position calculation, and MLC log files enabled fine-time scale analysis.
Main Results:
- Total latency from image acquisition to MLC adjustment was 380 ms (MV) and 420 ms (kV) at 150 ms imaging intervals.
- Image file writing constituted the largest latency component (272 ms for MV, 309 ms for kV).
- MLC adjustment time was constant for small movements (<1.1 mm) but increased linearly for larger adjustments.
Conclusions:
- A novel method for detailed temporal analysis of DMLC tracking signals was successfully developed and applied.
- The method effectively identifies major latency contributors, guiding efforts to reduce delays in image-based DMLC tracking.
- This technique is valuable for reconstructing delivered dose by synchronizing target and MLC motion.
