WE‐E‐AUD‐06: Clinical Prototype of a Plastic Water‐Equivalent Scintillating Fiber Dosimeter Matrix for IMRT QA Applications
Bibliographic record
Abstract
Purpose: To develop a clinical prototype of a plastic water‐equivalent scintillating fiber dosimeter array for IMRT beam quality assurance (QA) applications. Method and Materials: A clinical prototype of a scintillating fiber dosimeter array has been developed. The system comprises twenty‐nine (29) 1 mm diameter and 2 mm long (1,6 mm3) scintillating fiber detectors (BCF‐12, Saint‐Gobain, inc.) spaced 1 cm apart encapsulated in a Plastic Water (MedTec inc.) phantom. The detectors are coupled to clear non‐scintillating transport fibers (BCF‐98, Saint‐Gobain, inc.) that collect scintillation photons and transport them to a color charge‐coupled device (CCD) placed on the treatment table outside of the primary beam. A spectral discrimination technique is used to remove the Cerenkov radiation contaminating the scintillation signal. The CCD is encased in a custom designed, Cerrobend shielded aluminum carrying‐case equipped with a custom‐made optical fiber connector enabling reproducible removal and insertion of the fibers. Residual radiative noise on the CCD is removed with a post‐processing algorithm. All dose points are processed simultaneously. Results: Open field crossplane profiles from 4×4 to 20×20 cm2 and a 10×10 cm2 depth‐dose in Plastic Water are compared to ionization chamber (CC13, Wellhofer) measurements in water. The maximum in‐field relative difference across all points and measurements is found to be 0.9% for profiles and 1.6 % for the depth dose. The standard deviation on the scintillation detector response is smaller than 1% in‐field. The optical fiber connector insertion and removal is repeatable to within the measurement resolution (1%). This will allow for “hot swappable” detector modules. Conclusion: The scintillating fiber dosimeter array prototype is found to be accurate, precise and practical. The current system detector capacity exceeds 3500 measurement points per single irradiation. Such array detectors could find application for IMRT QA and general beam dosimetry monitoring measurements.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.003 |
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".