A liquid xenon detector for PET applications: simulated performance
Bibliographic record
Abstract
We are investigating a liquid xenon (LXe) gamma ray detector-based PET system for small animals. The proposed system consists of 12 modules arranged into a ring. Each detector module is a trapezoidal LXe time projection chamber (TPC) viewed by two arrays of large area avalanche photodiodes (LAAPD). We developed a Geant4-based Monte Carlo code to model the LXe PET system and study its imaging performance. Events depositing energy in multiple locations were reconstructed with a Compton reconstruction algorithm. The simulated data were stored in a list-mode file and reconstructed with the maximum likelihood expectation maximization iterative algorithm (MLEM). Simulation results indicate an absolute sensitivity at the center of the field of view (FOV) of 12.6% and a 3D position resolution ≤ 0.8 mm (FWHM) throughout the FOV. A simulated image of a micro-Derenzo phantom shows that rods of 0.6 mm diameter are visible.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".