Optical Coherence Tomography for the Evaluation of Energy Seals and the Subsequent Evaluation of the Thulium Laser as a Hemostatic Instrument
Notice bibliographique
Résumé
This thesis presents the development of a system which integrates both an Optical Coherence Tomography system and a high-powered Thulium fiber laser. The system was developed in order to study the interaction between Thulium laser and tissue via Optical Coherence Tomography feedback. This was done given the Thulium laser’s theoretical potential to serve as a multipurpose surgical instrument. The core work of the thesis is divided into two sections: 1. The development of an energy seal evaluation methodology using Optical Coherence Tomography. One-hundred and four avian embryonic vessels were subjected to Thulium laser irradiation at 1942 nm and subsequently imaged. Using both structural and Doppler feedback, several biomarkers were identified and used to classify irradiation outcomes as sealed or not sealed. The methodology developed here was compared to visual methodologies. It was found that the reported seal rate was dependent on the classification methodology (p = 0.01) where visual evaluation reported 18% more seals across the entire data set. The specificity of visual evaluation was dependent on the type of non-seal classification (p < 0.0001). Given that the developed methodology relied on the identification of biomarkers rather than user opinion, an objective evaluation methodology was achieved. Hemostatic systems evaluated visually should be re-evaluated. 2. Evaluating the Thulium laser as a hemostatic instrument. Average power, exposure time, and spot size were varied to maximize the seal rate. At sub 2 s exposure times the overall seal rate across all vessels was 29%. The highest seal rate achieved for a single condition was 60%. The rupture rate showed some correlation to average power. Biological factors were found to have a significant effect on the seal rate where the mean vessel diameter for non-seal outcomes was greater than that for seal outcomes (p < 0.001). Tissue dehydration was a factor in this study. The average heat affected zone was 2.2 ± 1.1 mm, typical of a hydrolytic laser. This finding affirmed that hydrolytic lasers can induce seals despite the dimensions of the optical zone. As irradiance increased so did the heat affected zone, the opposite was true for exposure time. Using a dose until seal approach the seal rate was 95% across 18 vessels. The average therapeutic time was 9 ± 3 s for single vessel. Based on the overall lack of predictability observed in interactions between Thulium laser and vascular tissue, as well as the relatively poor seal rates, the Thulium laser was not recommended to be used in hemostatic applications.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».