MO‐F‐110‐06: Developing Deformable 3D Dosimeters: Radiochromic Gels in Latex Balloons
Bibliographic record
Abstract
Purpose: To develop radiochromic hydrogels contained in latex balloons as a model for 3D dosimetry in deformable tissue. Methods: Films of latex solution were thermally cured to form thin sheets of transparent rubber. Spheroid, elastic dosimeters were made by filling adaptor tubes sealed at one end by circular rubber sheets with radiochromic hydrogel. These dosimeters were evaluated for optical and mechanical properties and dosimetric performance. Dosimeters were scanned with a fast 3D optical cone beam computed tomography system and dose distributions were reconstructed with isotropic 0.25 mm sized voxels. Gels were irradiated in a water tank to a uniform 3 Gy dose or by an array of 5 mm square beamlets in a grid pattern, with the dosimeter in either relaxed or deformed state. Four percent gelatin gels were employed in the study and dosimeter rigidity was adjustable by filling balloons with more gel. Dosimeters were maintained at a temperature of 20° C throughout the experiments. Deformed gels were allowed to return to the relaxed state for 30 minutes while the radiochromic reaction completed prior to CT scanning. Results: Ferrous ‐ xylenol orange ‐ gelatin hydrogels in latex balloons exhibited similar auto‐oxidation rates and dose sensitivities to samples contained in rigid plastic vessels. The thin‐walled latex balloons provided excellent optical transmission performance allowing accurate dosimetry to within 1 mm of the balloon wall. Uniform irradiations resulted in uniform dose reconstructions for both the relaxed and deformed dosimeters. Deformed gel irradiated with the beamlet array and scanned in relaxed state demonstrated ability of dosimeter to record 3D dose deformation patterns. Conclusions: The elastic properties of transparent films and hydrogels can be combined to produce deformable 3D radiochromic dosimeters compatible with optical CT scanners. These dosimeters can be used to validate multi‐ fraction dose accumulation algorithms based on image warping algorithms. A. Walsh supported by grant: Optimization of Radiation Therapy: Uncertainty Analysis and Strategies for Improvement. Canadian Institutes of Health Research #200403MOP‐128435‐BME‐CEEA‐11379
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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 | 0.000 | 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 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".