MO‐F‐214‐04: Protoyping Compositions of Novel Radiochromic Film Types: Towards Complete Absorbed Dose Energy Independence
Bibliographic record
Abstract
Purpose: To develop a new generation energy‐independent radiochromic film over a wide energy range of 50 kVp to 18 MV. The films are preferably symmetric in structure and can be used for measurements in complex spectral distributions. Methods: The overall energy dependence and intrinsic energy dependence were measured for EBT2 and several prototype films of known compositions. The intrinsic energy response is quantified through a measurement of total energy response divided by the Monte Carlo calculated absorbed dose energy response. The measurements consisted of delivering an exact dose of 2 Gy to the sensitive layer of the film at both orthovoltage energies (50kVp, 120kVp, and 180kVp) and 60Co beam. Thus far, two iterations have been performed, whereby; numerical simulations are used to obtain an optimized absorbed dose energy response that will undo for the film intrinsic energy response. DOSRZnrc user‐code of the EGSnrc Monte Carlo code was used for all simulations. AAPM TG51 and TG61 were used to determine the dose‐to‐water and air‐kerma in air in megavoltage and orthovoltage beams, respectively, while Monte Carlo simulated corrections were used to convert these results to the desired dose to film. Results: For EBT2 films the overall energy dependence was found to vary by 35% over 50 kVp to Co‐60 energy range. The latest prototype measured in this work has shown a total net variation of 8% over the same range. High atomic number elements (Chlorine and bromine) were found to affect absorbed dose response drastically. The iterative optimization technique has placed a large focus in accurately determining the elemental composition. Conclusions: We have quantified the intrinsic energy dependence of radiochromic films, and have used the data to numerically optimize the composition of the active layer to produce an energy‐ independent film with an 8% energy variation over a wide energy range. Funding: This work was supported by the Natural Sciences and Engineering Research Council of Canada contract No. 386009. Conflict of interest: ISP is a manufacturing company of GAFCHROMICTM films.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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 teacher head, 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".