Radioiodine uptake measurements at 24 hours are sufficient for the evaluation and therapy of hyperthyroidism.
Bibliographic record
Abstract
237 Objectives: Hyperthyroidism is commonly treated with thyroid radioiodine ablation with varying rates of success. Patients for whom initial treatment has failed often proceed to repeat radioiodine therapy. In this study, we aimed to retrospectively investigate factors that may impact initial treatment success, with particular attention to rapid iodine turnover as a cause of treatment failure. Methods Consecutive patients undergoing radioiodine treatment for hyperthyroidism between 2010 and 2014 at the Hospital of the University of Pennsylvania and at Pennsylvania Hospital were included. We evaluated all patients for whom repeat treatment was necessary. Patients’ charts were retrospectively reviewed for data regarding demographics, diagnosis, thyroid function tests, thyroid size, radioiodine uptake (RAIU), administered radioiodine treatment dose, and competing medications. Results A total of 269 patients with hyperthyroidism underwent initial thyroid radioiodine ablation. Patients were followed for a mean of 35.8 months (range 12-59 months). Fourteen (5%) of these patients required one retreatment for a total of 283 treatments overall. Thyroid uptake was measured at 2 hours and 24 hours in 9 of the retreated patients, with a mean 2- to 24-hour uptake ratio of 0.72 (range: 0.24 - 1.05); only one patient had a 2- to 24-hour ratio > 1 suggestive of rapid iodine turnover. In the other 5 retreated patients an uptake ratio could not be calculated because thyroid uptake was not measured at 2 hours; however, in these patients the mean 24 h uptake was markedly elevated, measuring 83% (range: 71 - 95%), thereby making rapid iodine turnover less likely. With regard to treatment dose, five of the retreated patients (36%) received a dose of radioiodine below our institutional target of 0.2 mCi per gram of thyroid tissue, due to treating physician discretion. The thyroid glad was markedly enlarged in these 5 cases, using thyroid volumes determined by ultrasound (n=4) or physical exam (n=1), with a mean size of 80 g (range: 54 - 124 g) yielding a mean dose of 0.12 mCi/g (range: 0.07 - 0.16 mCi/g). At the time of I-131 treatment none of the patients were taking concurrent anti-thyroid medications (such as methimazole or PTU), or had a recent iodine load (such as iodinated IV contrast). Conclusion Rapid iodine turnover does not appear to be a significant cause of treatment failure in patients undergoing radioiodine ablation for hyperthyroidism at our institution. In addition, the overall treatment failure rate (5%) at our institution seems to be low when a treatment dose of 0.2 mCi/g is adhered to. These findings are limited by the small sample size, and lack of 2-hour uptake measurements in some patients. Also, our treatment failure rate is likely underestimated because patients with recurrent hyperthyroidism that were not retreated with radioiodine, or were retreated at a different institution, were not included in our analysis. Thus, further study is needed.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".