Performance characterization of a novel hybrid dosimetry insert for simultaneous spatial, temporal, and motion‐included dosimetry for MR‐linac
Notice bibliographique
Résumé
Abstract Background Several (online) adaptive radiotherapy procedures are available to maximize healthy tissue sparing in the presence of inter/intrafractional motion during stereotactic body radiotherapy (SBRT) on an MR‐linac. The increased treatment complexity and the motion‐delivery interplay during these treatments require MR‐compatible motion phantoms with time‐resolved dosimeters to validate end‐to‐end workflows. This is not possible with currently available phantoms. Purpose Here, we demonstrate a new commercial hybrid film‐scintillator cassette, combining high spatial resolution radiochromic film with four time‐resolved plastic scintillator dosimeters (PSDs) in an MRI‐compatible motion phantom. Methods First, the PSD's performance for consistency, dose linearity, and pulse repetition frequency (PRF) dependence was evaluated using an RW3 solid water slab phantom. We then demonstrated the MRI4D scintillator cassette's suitability for time‐resolved and motion‐included quality assurance for adapt‐to‐shape (ATS), trailing, gating, and multileaf collimator (MLC) tracking adaptations on a 1.5 T MR‐linac. To do this, the cassette was inserted into the Quasar MRI4D phantom, which we used statically or programmed with artificial and patient‐derived motion. Simultaneously with dose measurements, the beam‐gating latency was estimated from the time difference between the target entering/leaving the gating window and the beam‐on/off times derived from the time‐resolved dose measurements. Results Experiments revealed excellent detector consistency (standard deviation 0.6%), dose linearity (R2 = 1), and only very low PRF dependence (0.4%). The dosimetry cassette demonstrated a near‐perfect agreement during an ATS workflow between the time‐resolved PSD and treatment planning system (TPS) dose (0%–2%). The high spatial resolution film measurements confirmed this with a 1%/1‐mm local gamma pass‐rate of 90%. When trailing patient‐derived prostate motion for a prostate SBRT delivery, the time‐resolved cassette measurements demonstrated how trailing mitigated the motion‐induced dose reductions from 1%–17% to 1%–2% compared to TPS dose. The cassette's simultaneously measured spatial dose distribution highlighted the dosimetric gain of trailing by improving the 3%/3‐mm local gamma pass‐rates from 80% to 97% compared to the static dose. Similarly, the cassette demonstrated the benefit of real‐time adaptations when compensating patient‐derived respiratory motion by showing how the TPS dose was restored from 2%–56% to 0%–12% (gating) and 1%–26% to 1%–7% (MLC tracking) differences. Larger differences are explainable by TPS‐PSD coregistration uncertainty combined with a steep dose gradient outside the PTV. The cassette also demonstrated how the spatial dose distributions were drastically improved by the real‐time adaptations with 1%/1‐mm local gamma pass‐rates that were increased from 8 to 79% (gating) and from 35 to 89% (MLC tracking). The cassette‐determined beam‐gating latency agreed within 12 ms with the ground truth latency measurement. Film and PSD dose agreed well for most cases (differences relative to TPS dose 4%), while film‐PSD coregistration uncertainty caused relative differences of 5%–8%. Conclusions This study demonstrates the excellent suitability of a new commercial hybrid film‐scintillator cassette for simultaneous spatial, temporal, and motion‐included dosimetry.
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 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 | 0,001 | 0,001 |
| 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 | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| 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 ».