Experimental investigation on the accuracy of plastic scintillators and of the spectrum discrimination method in small photon fields
Notice bibliographique
Résumé
Purpose To investigate the accuracy of output factor measurements using a commercial (Exradin W1, SI ) and a prototype, “in‐house” developed, plastic scintillation dosimeter ( PSD ) in small photon fields. Methods Repetitive detector‐specific output factor OF det measurements were performed in water (parallel to the CAX ) using two W1 PSD s ( SI ), a PTW microLion, a PTW microDiamond and an unshielded diode D1V ( SI ) to which Monte Carlo calculated corrections factors were applied. Four sets of repetitive measurements were performed with the W1 PSD positioned parallel and perpendicular to the CAX , each set on a different day, and with analytically calculated volume averaging corrections applied. The W1 OF det measurements were compared to measurements using an “in‐house” developed PSD in water ( CHUQ ) and both were validated against a previously commissioned Monte Carlo beam model in small photon fields. The performance of the spectrum discrimination calibration procedure was evaluated under different fiber orientations and wavelength threshold choices and the impact on the respective OF det was reported. Results For all detectors in the study an excellent agreement was observed down to a field size of 1 × 1 cm 2 . For the smallest field size of 0.5 × 0.5 cm 2 , the W1 PSD s presented OF det readings higher by 3.8 to 5.0% relative to the mean corrected OF det of the rest of the detectors and by 5.8 to 6.1% relative to the CHUQ PSD . The repetitive W1 OF det measurements in water (parallel CAX ) were higher by 3.9% relative to the OF det measurements in Solid Water TM (perpendicular CAX ) even after volume averaging corrections were applied, indicating a potential fiber orientation dependency in small fields. Uncertainties in jaw and detector repositioning as well as source variations with time were estimated to be less than 0.9% (1 σ ) for the W1 under both orientations. The CHUQ PSD agreed with the MC dose calculations in water, for the smallest field size, within 1.1–1.7% before any corrections and within 0.3–0.8% after volume averaging corrections. The spectrum discrimination method provided reproducible Cherenkov spectra under the different calibration set‐ups with noisier spectra extracted if the calibration is performed in water and parallel to the CAX . The impact of fiber orientation and wavelength threshold during calibration on OF det was in general minimal. Conclusions Clinically relevant differences were observed between similar scintillator dosimeters in photon fields smaller than 1 × 1 cm 2 . Further research on PSD s is needed that can explain the origin of these differences especially related to the Cherenkov spectrum dependencies on the optical fiber technical characteristics.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
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 tête enseignante, 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 ».