Poster — Thur Eve — 44: Short Term Development Effects of Gafchromic EBT2 Film
Bibliographic record
Abstract
Introduction: Gafchromic external beam therapy (EBT)2 is used in our clinic to verify the delivery of Tomotherapy patient plans. We have investigated the short term development effects of Gafchromic film up to 16 hours after irradiation. The importance of the scan position of the film along the active region of a Vidar Pro Dosimetry scanner is also studied. Materials/Methods: An EBT2 film is placed between two halves of a cylindrical phantom. A calibration plan which delivers dose in 13 predefined regions on the film is delivered on a Tomotherapy Hi‐ART 2 (Tomotherapy Inc., Madison WI) system. A point dose is taken within the phantom and used to determine the film irradiation response. The film was scanned using a Vidar Pro Dosimetry Advantage (Vidar, Herndon, VA, USA) scanner. The film was scanned after irradiation at times ranging from 5 minutes to 16 hours. The importance of the film position along the scanner active region was investigated by scanning the film under two conditions: at the edge of the scanner and at the middle of the scanner. Results/Discussion: One hour after irradiation the film had developed to 98.5 % of the measured OD at 16 hours, while after 2 hours, the film had developed to approximately 99 % of the measured OD at 16 hours. Specific to our calibration file setup, we measured a difference of 4.7 % in the 54 cGy region. This large difference could be important when using film to determine the acceptance of patient plans.
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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 | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.018 | 0.002 |
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".