Poster — Wed Eve—22: Measurement of Imaging and Treatment Time Delays in Gated Radiotherapy
Bibliographic record
Abstract
In gated radiotherapy, the accuracy of treatment delivery is determined by the accuracy with which both the imaging and treatment beams are gated. The time delay is the time between when the markers enter or leave the specified position range for amplitude based gating, or phase for phase based gating, and when an image is obtained or linear accelerator beam starts or ceases delivery. We measured time delay for three fluoroscopy systems and three linear accelerator treatment beams, varying gating type (amplitude vs. phase), beam energy, dose rate, and period. In the system we studied, the treatment beam was turned on and off later than expected by 0.08 ± 0.03s (1 SD). Retrospectively gated fluoroscopy systems had time delays in the opposite direction, indicating the images appeared to have been acquired earlier than they had in reality. The average beam on imaging time delays were −0.04 ± 0.05s (amplitude,), −0.11 ± 0.04s (phase); while the average beam off imaging time delays were −0.18 ± 0.08s (amplitude) and −0.15 ± 0.04s (phase). In this case, the asynchronous time delays for the imaging and treatment systems add linearly. We measure and model the effect of asynchronous time delays on gated deliveries and discuss their implications.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".