Simulation-corrected focusing to the vertebral canal
Bibliographic record
Abstract
Phased arrays have long been used to deliver focused ultrasound to the brain, but applications in the spinal cord remain comparatively unexplored. This is largely due to the aberrating effect of vertebral bone on the incoming wavefront, where variable density and complex geometry distort the pressure field in the canal. For controlled focusing, phase and amplitude corrections must therefore be calculated in advance. Here, we validate a previously-developed ray acoustics model for transvertebral focusing with a bilateral spine-specific array. Benchtop trials were conducted with ex vivo human vertebrae and ray acoustics beamforming was compared to a geometric baseline and hydrophone-corrected gold standard. Planar shift in the 90% contour was evaluated via raster scans of the sagittal and coronal planes. Ray acoustics correction reduced mean sagittal shift from 1.76 ± 0.79 mm to 1.63 ± 0.86 mm and reduced mean coronal shift from 0.99 ± 0.54 mm to 0.76 ± 0.63 mm, while hydrophone correction produced mean sagittal and coronal shifts of 1.40 ± 0.83 mm and 0.53 ± 0.47 mm, respectively. Large variance in simulation-corrected results is hypothesized to stem from nonuniform attenuation and intervertebral acoustic windows, a possibility that will be explored in future in silico and benchtop work.
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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 | 0.000 | 0.001 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".