Control charts for evaluation of quality of low-dose-rate brachytherapy for prostate cancer
Bibliographic record
Abstract
Purpose: Variations in dosimetric outcomes among patients treated with low-dose-rate brachytherapy for prostate cancer exist, even when implants are within dose constraints.Here, we used control charts to investigate reasons for intra-patient dosimetric variability.Material and methods: Univariate and multivariate control charts for prostate V 100 (percentage of prostate volume that received 100% of prescribed radiation dose), D 90 (radiation dose to 90% of prostate volume), and RV 100 (rectal wall volume that received 100% of prescribed radiation dose) were generated for 212 consecutive prostate cancer patients implanted with iodine-125 ( 125 I) radioactive seeds at the Princess Margaret Cancer Centre.Control limits were calculated based on the first fifty implants.Data points that were out of control were identified, and their pre-treatment and post-treatment dosimetric and clinical parameters were compared to data points that were in-control, using Student's t-test.Results: All implants were clinically acceptable.Twelve data points exceeded multivariate control limits.Ten of those points fell below the lower control limit of V 100 control chart.Average prostate edema in the 10 out-of-control patients on both multivariate and V 100 charts was 8.3%, as compared to 0.4% for in-control patients (p < 0.04).Two patients were observed to be out-of-control on multivariate control chart, but not on V 100 control chart, and were found to have a reduction in prostate volume of 19.1% and 20.1% at one month after seed implant, compared to prostate volumes of pre-implantation evaluations.Conclusions: Control charts helped in identifying cases with out-of-control variability in post-plan prostate dosimetry.Post-treatment prostatic edema and contraction are important factors predicting variability in patients treated with 125 I permanent seed brachytherapy.
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 | 0.010 | 0.033 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".