Dose threshold values for endovascular photodynamic therapy (PDT) in normal pig pancreas and human pancreatic cancer
Bibliographic record
Abstract
BACKGROUND: Pancreatic cancers often involve major blood vessels, making complete surgical removal difficult or impossible. We are developing endovascular photodynamic therapy (PDT) as a novel minimally invasive ablation method to clear tumours from these vessels, to enable potentially curative surgery. The goal is to determine the required endovascular irradiation times for effective treatment. METHODS: Threshold doses for PDT were estimated using Monte Carlo simulations, based on clinical data from previous Phase I/II studies involving Photodynamic Therapy of pancreatic cancer using interstitial needle-based irradiation. These thresholds were then compared to our recent in vivo study, which used endovascular catheter-based irradiation in a normal pig pancreas. Using these dose thresholds, we estimated the PDT irradiation times needed to achieve necrotic tissue margins of 4-12 mm around blood vessels in pancreatic cancer patients, based on a fixed energy range and increasing doses of photosensitiser. RESULTS: @ 690 nm, necrotic margins of circa 8 mm beyond the vessel adventitia can be anticipated in pancreatic cancer patients. The required irradiation times range from 337 to 636 s, inversely related to vessel diameters of 10 mm and 3 mm, respectively. CONCLUSIONS: These findings suggest that PDT can potentially create a margin around major pancreatic blood vessels free of viable tumour tissue. The calculated dosimetry supports the feasibility of clinical application using the proposed Verteporfin dose and light delivery parameters, warranting further investigation in Clinical trials.
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How this classification was reachedexpand
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".