WE‐C‐108‐10: Model‐Based Dose Calculations for Eye Plaque Brachytherapy
Bibliographic record
Abstract
Purpose: To develop a comprehensive understanding of dosimetry for ocular brachytherapy through model‐based dose calculations involving a full human eye model for various plaque models and three different photon‐emitting radionuclides (125I, 103Pd and 131Cs). Methods: A representative computational model of the human eye and surrounding tissues was developed based on ocular geometry and compositions from the literature. Mass energy absorption and attenuation coefficients for all media were calculated. Monte Carlo simulations using the EGSnrc user‐code BrachyDose were performed for a variety of photon‐emitting plaques covering the range of plaque models encountered in clinical practice, including the widely‐used COMS plaque. Maximum, minimum and average doses to ocular structures, as well as dose volume histograms (DVH) for the full eye model were compared to those for a homogeneous water phantom, both including and excluding (TG‐43) inter‐seed and eye plaque effects. Results: Mass energy absorption and attenuation coefficients for ocular media differ from those for water by up to 10% for photon energies in the 10–30 keV range. For the COMS plaque in the full eye model, average doses to important structures such as the tumour and lens differ from those for the plaque in water by roughly 8–10% and 13–14%, respectively, and from TG– 43 calculation by 2–17% and 29–34%, respectively. Maximum, minimum and average doses differ considerably from doses to points of interest (as they are currently reported); the lens has a larger average dose by 7–9% and optic nerve has a larger maximum dose by 16–22%, than at the center of the lens and the optic disk, respectively. Conclusion: Dose distributions for the full eye model simulations deviate significantly from TG‐43 and from simulations that include the plaque but assume the eye to be water equivalent, highlighting the need for accurate model‐based dose calculations in ocular brachytherapy. Funding support: NSERC, OGS
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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".