Quantitative assessment of the radon (222Rn) decay product 210Pb in human toenails as a sensitive measure of personalized long-term radon gas exposure history
Bibliographic record
Abstract
Lung cancer mortality can be lowered through early-diagnostic screening of people demonstrating a ≥1.5 % 6-year risk of tumor development. However, many who develop lung cancer are ineligible for screening (∼40 % of Canadian patients) as they have insufficient tobacco smoking history. Tools to assess individual lung cancer risk based on exposure to other prevalent environmental carcinogens such as radon ( 222 Rn) gas are lacking. Here, we explore ultrasensitive quantification of the 222 Rn decay product 210 Pb in toenails (n = 39) as an indicator of personalized, long-term radon exposure history. Toenail cuttings from adults inhaling elevated indoor radon in their primary house (average radon = 354.9 Bq/m 3 ) over a mean of 26.5y (equating to 427 mSv radiation dose) contained 0.298 femtograms of 210 Pb per nanogram of stable Pb. By contrast, only 0.075 femtograms 210 Pb per nanogram Pb were detected in toenails from low radon exposure controls (28.4 Bq/m 3 over 22.5y equating to 22.8 mSv) – a 397 % difference. Notably, elevated radon decay products (0.245 femtograms of 210 Pb per nanogram Pb) persisted in toenails from highly radon-exposed people (545.6 Bq/m 3 over 18.5y equating to 283 mSv) who, up to 6 years prior to toenail collection, had mitigated their primary residence to reduce radon (post-mitigation radon = 28.1 Bq/m 3 ). No differences were detected on the basis of sex, age, tobacco smoking history, or 210 Pb-rich game meat consumption. These data suggest that toenail 210 Pb/Pb isotope (amount) ratios show promise for evaluating individualized retrospective radon dosimetry history – an approach that may become helpful to assess non-tobacco lung cancer risk in the future.
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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 | 0.001 | 0.000 |
| 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 | 0.001 |
| 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 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".