Absolute measurement of absorbed dose to water for γ-ray of 60Co by water calorimetry
Bibliographic record
Abstract
BackgroundMost of domestic radiation therapy doses can only be traced back to air kerma of 60Co γ-ray at present in China. The uncertainty of directly tracing radiation therapy dose to absorbed dose to water is much smaller compared to tracing radiation therapy dose to air kerma, which must be converted to absorbed dose to water.PurposeThis study aims to solve the problem of traceability and transfer of 60Co γ-ray absorbed dose to water, as well as the problem that the dose measurement of radiotherapy cannot be directly traced through the absorbed dose to water, NIMTT (National Institute of Measurement and Testing Technology) has established an absolute measurement device of 60Co γ-ray absorbed dose to water.MethodsAn absolute measurement device of 60Co γ-ray absorbed dose to water was established by National Institute of Measurement and Testing Technology (NIMTT) using water calorimeterfor direct measurement of absorbed dose to water. The correction factors for water absorbed dose measurement were obtained by experimental and simulation methods. A comparison of laboratory reproducing results was made between NIMTT and NRC (National Research Council, Canada) using the method of transmitting standard to further verify the accuracy and consistency of the measurement of 60Co γ-ray absorbed dose to water. Two PTW ionization chambers were used as the transfer standard.ResultsThe reproduced results of two laboratories for absolute measurement of 60Co γ-ray absorbed dose to water are consistent within the relative standard uncertainty of 0.71%, and the normalized error value of En is -0.45.ConclusionsThe comparison results have verified that NIMTT laboratory has the ability of traceability and transmission of absorbed dose to water. The results of this study provide a reference for the absolute measurement of absorbed dose to water for 60Co γ-ray.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".