Operational characteristics of a prototype x-ray needle device
Bibliographic record
Abstract
A prototype x-ray needle, which emits 62.5 kVp x-rays at the tip of a 20 cm long, 4 mm diameter steel needle, has been developed by Titan Pulse Sciences Incorporated (PSI) (Albuquerque, NM) and was tested for its suitability in brachytherapy applications in comparison with a similar device by the Photoelectron Corporation. The depth dose profiles were also compared with those of two common brachytherapy sources (125I and 192Ir). The depth dose characteristics of the radiation were comparable with the two brachytherapy sources with a slightly reduced attenuation gradient. The dose rate from the x-ray needle tip was relatively isotropic at the needle tip and was continuously adjustable over the range of 0 cGy min(-1) to upwards of 62 cGy min(-1) at a reference distance of 1 cm in air. We detected a significant proportion of x-rays generated along the needle shaft, and not at the needle tip, as intended. The energy spectrum emitted from this device had a peak intensity at 21 keV and an average energy of 28 keV. The beam was attenuated in both aluminium (the first half-value layer being less than 0.1 mm) and in water (50% dose at approximately 2 mm). These studies confirm that although there is potential for a system similar to this one for clinical applications, the simplistic electron guidance used in this particular prototype device limits it to research applications. Further optimization is required in focusing and steering the electron beam to the target, improving x-ray production efficiency and using x-ray target cooling to achieve higher dose rates.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".