SU‐GG‐T‐05: MOSFET In‐Vivo Dosimetry for Colorectal Cancer Patients Treated with Shielded Brachytherapy
Bibliographic record
Abstract
Purpose: To investigate the suitability of MOSFET detectors as in‐vivo dosimeters for shielded colorectal brachytherapy. Method and Materials: A silicone applicator used in colorectal brachytherapy treatments was located at the middle of a water tank with an source in one catheter and two MOSFETs in two other ones. The dose was measured as a function of the distance and the angle from the source without and with a shielding rod in the applicator. In order to correct the measurement of the detector over‐response, the MOSFET energy dependence was calculated by the Monte Carlo (MC) code MCNPX2.5 and a correction factor was determined for each measurement point. Then, the measured corrected doses were compared to TG‐43 calculations for measurements without shielding and an in‐house dose‐kernel superposition method based on MC dose calculations for measurements with shielding. Results: The calculated MOSFET energy dependence shows an over‐response below 200 keV with a maximum at 40 keV by a factor 6.4 due to the dominant contribution from the photoelectric effect in Si02. Without shielding, the comparison between the measured dose and the dose calculated with TG‐43 shows a good agreement with a ±5% relative difference. With shielding, the comparison between the measured and the calculated dose gives a relative difference between 10% and 15% for the measurement point in the catheter at 90° from the source, and between 5% and 10% when the MOSFET is behind the shielding. Conclusion: For colorectal cancer patients the application of an energy response correction factor leads to good agreement between MOSFET measured and calculated doses when the shielding is not inserted. With the shielding, the discrepancy between measurement and calculation is higher, between 5% and 15%.
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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 | 0.001 |
| 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".