Sci-Fri AM(2): Brachy-02: Realizing Absorbed Dose Directly for HDR Ir-192 Brachytherapy: Water Calorimetry and comparison to Ion Chamber, Gafchromic Film, and TG-43
Bibliographic record
Abstract
A new standard based on direct measurement of absolute absorbed dose to water in HDR brachytherapy using water calorimetry is discussed. The calorimetry results are compared with the results from the in-water measurement of absorbed dose using ionization chamber and EBT Gafchromic film reference dosimetry, as well as TG-43. The water calorimetry measurements were performed using a spring-loaded catheter holder system that mounts onto a parallel-plate calorimetric vessel. The COMSOL MULTIPHYSICS™ software was used to perform the numerical heat-transport calculations. The calorimetric measurements were performed with three different sources with nominal ranging from 31600–36940 U (i.e. 7.6–9.2 Ci activity) over a one-year period. A source-to-detector separation ranging between 51–67 mm, and an irradiation time ranging between 200–300 s were used. Based on water calorimetry, an average dose rate to water of 361±11 μGy/(h.U) at mm was measured. Chamber reference dosimetry resulted in a dose rate measurement of 366±9 μGy/(h.U), while EBT Gafchromic film reference dosimetry resulted in 368±11 μGy/(h.U). From TG-43 protocol, we obtain a value of 364±15 μGy/(h.U), a 0.8% difference from water calorimetry. All Results agree well to within uncertainty. Our work paves the way to successful primary absorbed dose determination for using calorimetric techniques.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".