Phantom testing of two clinical spatially‐resolved NIRS instruments
Bibliographic record
Abstract
We used a living biological phantom to evaluate whether previously observed clinical differences in data collection between two similar near infrared spectrophotometers were due to technical design differences. A Somanetics INVOS‐5100 was compared to a Hamamatsu NIRO‐300. Both express the ratio of oxygenated hemoglobin to total hemoglobin concentration as a percentage, and both are intended for monitoring cerebral oxygenation status at the bedside. The living phantom simulated different bone densities and contained a low haematocrit solution of blood, intra‐lipid, and saline, to which was added grower′s yeast to alter oxygenation status. Results: In all trials, oxygen saturation decreased from 100% to 0 % as the yeast consumed the available oxygen. In all trials the spectrometers were significantly correlated (range: r2=0.815 to 0.995, p2>0.232). The NIRO‐300 indicated oxygenation change 1 minute after addition of yeast, whereas the INVOS‐5100 showed change after 5 minutes. Simulated bone thickness had almost no effect upon the NIRO‐300, but did affect the INVOS‐5100. Conclusion: In this study, the spectrophotometers had similar results consistent with the technical design differences: the INVOS‐5100 does not report hemoglobin saturation change above 95% or below 15% while the NIRO‐300 reports the full range from 100% to 0%.
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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 | 0.004 | 0.014 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".