Feasibility of <i>in vivo</i> 3D microCT imaging of cortical bone vascular porosity in the rat
Bibliographic record
Abstract
Cortical bone is a dynamic tissue which undergoes adaptive and pathological changes through life. An improved understanding of the spatio‐temporal nature of these changes holds great promise for aiding the study of bone development, maintenance and senescence. Commercial in vivo microCT scanners operate with maximal resolutions in the 10–20 um range producing doses of 0.5–1 Gy for trabecular bone imaging. As dose scales exponentially with resolution, in vivo visualization of cortical microarchitecture remains beyond the reach of these systems. This study explored the feasibility of utilizing synchrotron propagation phase contrast microCT to resolve vascular porosity in the cortex of rat bone with doses suitable for in vivo imaging. We imaged ex vivo rat distal limbs at the Canadian Light Source synchrotron, determined the optimal propagation distance and used ion chamber and thermoluminescent dosimetry to measure dose. We found that 10 um resolution with 0.6 m of propagation distance at 37 keV was sufficient to visualize cortical pores with doses in the range of 2–4 Gy. Further optimization of the scan protocol promises to reduce dose to levels comparable to conventional trabecular bone scans. Grant Funding Source : NSERC
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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 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".