Sci‐Sat AM(2): Brachy‐01: A novel HDR Ir‐192 brachytherapy water calorimeter standard
Bibliographic record
Abstract
Parameters influencing the accuracy of absorbed dose measurements for HDR brachytherapy using water calorimetry were investigated with the goal to develop a novel primary absorbed dose to water standard. To provide greater stability, flexibility, and accuracy in the source‐detector distance d src‐det positioning and measurement, a new spring‐loaded catheter holder composed of two concentric cylindrical sleeves with multiple orthogonal adjusting screws was developed. The absorbed dose from Nucletron microSelectron‐HDR brachytherapy sources with air kerma strengths ranging between 21000–38000 U was studied. d src‐det is optimized so as to balance signal‐to‐noise ratio (decreasing with increasing d src‐det ) and temperature drift effects resulting from source self‐heating. The irradiation times were adjusted to yield a minimum 1 Gy of dose at the measurement point. Successful measurements at d src‐det ranging between 25–50 mm were performed. COMSOL MULTIPHYSICS™ software was used to determine the heat loss correction due to conduction defined as the ratio between temperature rise at a point under ideal conditions to realistic conditions (i.e., no conduction). An agreement of better than 6.5% was observed between TG‐43 calculated and calorimetrically measured absorbed dose rates. The effects of convection where calculated to be negligible as the glass vessel provides a convective barrier significantly decoupling the water velocity in the interior and exterior of the vessel (water velocities were 1–2 orders of magnitude different). Our work paves the way to successful primary absorbed dose determination for radioactive sources using calorimetric techniques.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".