RapidBrachyIVBT: A dosimetry software for patient‐specific intravascular brachytherapy dose calculations on optical coherence tomography images
Bibliographic record
Abstract
Abstract Background Coronary artery disease is the most common form of cardiovascular disease. It is caused by excess plaque along the arterial wall, blocking blood flow to the heart (stenosis). A percutaneous coronary intervention widens the arterial wall with the inflation of a balloon inside the lesion area and leaves behind a metal stent to prevent re‐narrowing of the artery (restenosis). However, in‐stent restenosis may occur due to damage to the arterial wall tissue, triggering neointimal hyperplasia, producing fibrotic and calcified plaques and narrowing the artery again. Drug‐eluting stents, which slowly release medication to inhibit neointimal hyperplasia, are used to prevent in‐stent restenosis but fail up to 20% of cases. Coronary intravascular brachytherapy (IVBT), which uses ‐emitting radionuclides to prevent in‐stent restenosis, is used in these failed cases to prevent in‐stent restenosis. However, current clinical dosimetry for IVBT is water‐based, and heterogeneities such as the guidewire of the IVBT device, fibrotic and calcified plaques and stents are not considered. Purpose This study aimed to develop a Monte Carlo‐based dose calculation software, accounting for patient‐specific geometry from Optical Coherence Tomography (OCT) images. Methods RapidBrachyIVBT, a Monte Carlo dose calculation software based on the Geant4 toolkit v. 10.02.p02, was developed and integrated into RapidBrachyMCTPS, a treatment planning system for brachytherapy applications. The only commercially available IVBT delivery system, the Novoste Beta‐Cath 3.5F, with a source train, was modeled with 30, 40, and 60 mm source train lengths. The software was validated with published TG‐149 parameters compared to Monte Carlo simulations in water. The dose calculation engine was tested with OCT images from a patient undergoing coronary IVBT for recurrent in‐stent restenosis at Brigham and Women's Hospital in Boston, Massachusetts. Considering the heterogeneities, the images were segmented and used to calculate the absorbed dose to water and the absorbed dose to medium. The prescribed dose was normalized to 23 Gy at 2.0 mm from the source center, which is the target volume in IVBT. Results The dose rate values in water obtained using RapidBrachyIVBT aligned with TG‐149 consensus values, showing agreement within a range of 0.03% to 1.7%. Considering the heterogeneities present in the patient's OCT images, the absorbed dose in the entire artery segment was up to 77.5% lower, while within the target volume, it was up to 56.6% lower, compared to the dose calculated in a homogeneous water phantom. Conclusion RapidBrachyIVBT, a Monte Carlo dose calculation software for IVBT, was developed and successfully integrated into RapidBrachyMCTPS, a treatment planning system for brachytherapy applications, where accurate attenuation of the absorbed dose by heterogeneities is considered.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.018 | 0.004 |
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".