Sci‐Sat AM (1) General‐02: Experiences with the Quality Assurance Testing of the Restitu Ultrasound System
Bibliographic record
Abstract
The BC Cancer Agency — Vancouver Island Centre recently acquired the new Restitu three‐dimensional ultrasound (US) system (Resonant Medical, Montreal) for performing prostate image‐guided radiation therapy. The system consists of an US assembly, with a free hand US probe and an optical tracking device, installed in both the CT simulation room (US Sim) and the linac suite (US Guide). Daily prostate misalignments are determined by comparing US images acquired at US Guide to US images acquired at time of planning CT. This work presents preliminary results from our on‐going quality assurance (QA) program to monitor performance of the Restitu system. Weekly and monthly tests use a QA phantom supplied by Resonant Medical with an embedded spherical target, rods and wires. Setup and imaging of the phantom is found to be highly reproducible with a standard deviation (SD) of < 0.5 mm for measures of target position. Deviations of measured target position relative to predicted position have all been < 2.1 mm (SD = 0.8 mm), misalignments between US Sim and US Guide < 2.5mm (SD = 1.2 mm) and re‐positioning errors < 1.5mm (SD = 0.6 mm). Deviations from predicted values of > 2 mm have only been measured once and 2 mm is recommended as the tolerance for system re‐calibration. Additionally, a phantom with a single embedded ellipsoid target has been constructed in‐house for daily QA purposes. Results indicate this inexpensive phantom is simple to use and provides a reliable means of testing daily for consistency of target position.
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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 | 0.016 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.016 | 0.006 |
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".