Commissioning of an Upgraded Equinox-100 Cobalt-60 Radiation Therapy Unit in the Varian Eclipse Treatment Planning System
Bibliographic record
Abstract
The introduction of Cobalt 60 (Co 60) units in the 1950s established megavoltage radiation therapy worldwide. Unfortunately, advances for the Co 60 radiation treatment units were not heavily pursued over the years and Co 60 units have been steadily replaced by clinical linear accelerators (linacs) x ray systems, which can offer more precise radiation treatments. The Medical Physics Department at the Cancer Centre of Southeastern Ontario (CCSEO) has shown, however, that the Co 60 unit can be developed to enable modern radiation treatments similar to linacs. In 2015, the CCSEO collaborated with Best Theratronics (Kanata, Ontario) to upgrade a Theratron 780C Co 60 radiation therapy unit to an Equinox 100 external beam radiation therapy system. This was the first upgrade of a T780C Co-60 unit in the world, which represents an exciting opportunity to advance Co 60 radiation therapy to provide treatments equivalent to those available from modern linacs. In this thesis, an upgraded Equinox 100 unit is commissioned in the Varian Eclipse treatment planning systems (TPS) to ascertain if the Analytical Anisotropic Algorithm (AAA) in the Eclipse could be used to generate Co 60 3D based treatment plans. Firstly, mechanical commissioning of the upgraded unit was performed according to Task Group 45 report (AAPM) recommendations. Secondly, various commissioning beam measurements were acquired using an ion chamber in standard water phantom on the upgraded unit to model the beams in the Eclipse TPS. The AAA validation was performed to test the accuracy of the Eclipse TPS dose prediction based on the local percentage differences between the measurements and the Eclipse model calculations in various simple open and blocked plans using the ion chamber in the phantom. The mechanical acceptance tests are generally comparable to clinical linac tolerances, which suggest that upgrading conventional Co 60 units may improve treatments without compromising the mechanical accuracy. Similarly, the Eclipse model calculations of the validation plans show overall excellent agreements with measurements within the recommended clinical criteria for large fields starting at 5 × 5 cm2. This suggests that the Eclipse TPS is appropriate for forward planning of Co 60 3D conformal radiation therapy for large fields. Further investigations for small fields are required.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".