SU‐E‐T‐419: To Validate Dose Delivery in Static Field Stereotactic Body Radiation Therapy (SBRT) of Lung Cancer
Bibliographic record
Abstract
Purpose: To validate dose delivery in static field stereotactic body radiation therapy (SBRT) of lung cancerMethods: An Exradin A16 0.007cc ion chamber, EBT3 Gafchromic film and Fricke‐Xylenol‐Orange‐Gelatin (FXG) gel dose measurements were performed providing measurements for point, planar and volumetric dose comparisons. CT images (GE Lightspeed RT16 CTSIM) of a Quasar respiratory motion phantom (Modus Medical) with stationary and moving inserts were acquired. Respiratory motion was recorded using a Varian RPM system. Standard cedar inserts with 3cm diameter solid tumors for the ion chamber and film, and an in‐house fabricated custom insert for FXG gel were used. Internal target volumes (ITV) were obtained from 4DCT scans. A typical 15BPM, 20mm amplitude peak‐to‐peak breathing pattern for ion chamber; and sinusoidal 15BPM/10mm respiratory cycles for film and gel dosimetry were used. Nine‐field SBRT plans using 6MV beams were calculated on Eclipse treatment planning system (v10.0; Varian). CBCT scans were used to reproduce the treatment setup; and irradiations were performed on a Trilogy (Varian) linear accelerator. Percentage dose difference and gamma analysis for 3% dose difference and 3mm distance‐to‐agreement were used to compare measured and calculated dose distributions. Results: Measured vs. calculated point dose differences (at a point inside the ITV) for the moving insert geometry were −2.1%, −1.5% and −0.5% for the ion chamber, film and gel measurements, respectively. The planar and volumetric gamma analysis of measured and calculated dose distributions for moving insert geometry showed 99.9% agreements for both EBT3 film and FXG gel dosimetry. Similar comparisons for a stationary insert geometry showed 100% and 98.5% agreements for film and gel measurements, respectively. Conclusion: A consistent level of agreement observed between measured and calculated doses for the point, planar and volumetric dose measurements validates the lung SBRT dose delivery. Research funding support provided by the Canadian Institutes of Health Research (CIHR)
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".