Commissioning of Bilateral (Parallel Opposed) Extended Source-to-surface Distance Total Body Irradiation Technique and Its Long-term Stability
Bibliographic record
Abstract
Aim: This article describes the commissioning of a total body irradiation (TBI) technique using bilateral-parallel-opposed fields at extended source-to-surface distance (SSD). Material: The measurements are based on the actual patient treatment geometry, which requires the patient to be placed inside a Perspex box. The gaps between the patient and the walls of the Perspex box were filled with rice bags to achieve full scattering conditions. The TBI box's lateral separation can be adjusted to 42 cm, 52 cm, or 62 cm by inserting the removable side walls to either of the three pairs of slots. A Farmer chamber, inserted inside a water-equivalent plastic slab phantom placed under full scattering conditions, was used for depth dose and profile measurements. The extended SSD was 333.5 cm, and the available field size was 132 cm × 132 cm. For output measurement, dose-to-water calibration factors for 6 MV and 15 MV energies were derived for the extended SSD. Bilateral-opposed fields were measured at three different separations to calculate lateral tissue effects. Result: For the 6 MV and 15 MV beams at a 42 cm separation, the midline-to-surface dose ratios were 1:1.17 and 1:1.08, respectively. As the separation increased, this ratio increased faster for the 6 MV beam and slower for the 15 MV beam. For the end-to-end quality assurance test (monitor unit to dose verification), the noted deviations were - 2.16% for the 6 MV beam and - 1.27% for the 15 MV beam. Conclusion: This article presents the detailed commissioning and long-term stability of the extended SSD TBI technique.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".