Evaluating the biological impact of increased scattered radiation in single and composite field radiation beams
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract Low energy scattered particles cause the average energy at the treatment field edge to be lower relative to the center of the beam. These particles have a higher LET, making them more biologically damaging. With a single beam (large field-size (FS)), the amount of these highly damaging electrons is low relative to within the treatment beam. However, when multiple beam angles and smaller FS are used (IMRT/VMAT), the relative contribution of scattered radiation increases and biological consequences may vary. The purpose of this study was to evaluate the theoretical impact of increased scattered radiation in single and composite field beams. Monte Carlo Geant4.10.3 was used to score the electron energy spectra at different depths in water with a 6 MV photon beam incident. The energy spectra were then used to calculate the maximum RBE, RBE M . Beams examined were phase-spaces of a Varian Clinac 600C 6 MV linac (10 × 10 cm 2 beam, 1 × 1 cm 2 beam), and a composite 10 × 10 cm 2 beam. The composite 10 × 10 cm 2 treatment field (simple IMRT) was created by summating one hundred 1 × 1 cm 2 beams to form a relatively uniform 10 × 10 cm 2 field. For smaller FS (1.5 cm depth), an increase in RBE M was seen 5.2 cm outside the beam (17%). The 10 × 10 cm 2 beam showed an increase of 14%, 9.2 cm away from beam’s edge (1.5 cm depth). The composite 10 × 10 cm 2 beam exhibited similar RBE M enhancement to the 10 × 10 cm 2 phase-space, however, the region of increased damage occurred closer to the beam (5.6 cm away). The results indicate that although the region inside the primary beam is not affected, the contribution of damaging particles happens much closer to the beam’s edge in the composite field case relative to an open field. This may have potential implications regarding the effective dose to organs at risk during radiotherapy.
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.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 it