An international multi-center investigation on the accuracy of radionuclide calibrators in nuclear medicine theranostics
Bibliographic record
Abstract
Abstract Background: Personalized molecular radiotherapy based on theranostics requires accurate quantification of the amount of radiopharmaceutical activity administered to patients both in diagnostic and therapeutic applications. This international multi-center study aims to investigate the clinical measurement accuracy of radionuclide calibrators for 7 radionuclides used in theranostics: 99m Tc, 111 In, 123 I, 124 I, 131 I, 177 Lu and 90 Y. Methods: In total, 32 radionuclide calibrators from 8 hospitals located in the Netherlands, Belgium and Germany were tested. For each radionuclide, a set of four samples comprising two clinical containers (10-mL glass vial and 3-mL syringe) with two filling volumes were measured. The reference value of each sample was determined by two certified radioactivity calibration centers (SCK CEN and JRC) using two secondary standard ionization chambers. The deviation in measured activity with respect to the reference value was determined for each radionuclide and each measurement geometry. In addition, the combined systematic deviation of activity measurements in a theranostic setting was evaluated for 5 clinically-relevant theranostic pairs: 131 I/ 123 I, 131 I/ 124 I, 177 Lu/ 111 In, 90 Y/ 99m Tc and 90 Y/ 111 In. Results: For 99m Tc, 131 I, and 177 Lu, a small minority of measurements were not within ±5% range from the reference activity (percentage of measurements not within range: 99m Tc: 6%, 131 I: 14%, 177 Lu: 24%) and almost none were outside ±10% range. However, for 111 In, 123 I, 124 I and 90 Y more than half of all measurements were not accurate within ±5% range ( 111 In: 51%, 123 I: 83%, 124 I: 63%, 90 Y: 61%) and not all were within ±10% margin ( 111 In: 22%, 123 I: 35%, 124 I: 15%, 90 Y: 25%). A large variability in measurement accuracy was observed between radionuclide calibrator systems, type of sample container (vial vs syringe), and source-geometry calibration/correction settings used. Consequently, we observed large combined deviations (percentage deviation > ±10%) for the investigated theranostic pairs, in particular for 90 Y/ 111 In, 131 I/ 123 I and 90 Y/ 99m Tc. Conclusions: Our study shows that substantial over- or under-estimation of therapeutic patient doses are likely to occur in a theranostic setting due to errors in the assessment of radioactivity with radionuclide calibrators. These findings underline the importance of thorough validation of radionuclide calibrator systems for each clinically-relevant radionuclide and sample geometry.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".