Delta4 Discover transmission detector: A comprehensive characterization for in-vivo VMAT monitoring

Petrucci, Edoardo; Radici, Lorenzo; Borca, Valeria Casanova; Ferrario, Silvia; Paolini, Marina; Pasquino, Massimo

doi:10.1016/j.ejmp.2021.04.017

Cited by 8 publications

(4 citation statements)

References 26 publications

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“…Los sistemas basados en cámaras de transmisión recogen y analizan la señal a la salida del cabezal de la unidad de tratamiento y la comparan con la señal predicha para analizar desviaciones durante el tratamiento. 160,258 Por otro lado, la dosimetría in vivo se define como una medida de radiación que se adquiere durante el tratamiento de un paciente y que contiene información acerca de la dosis absorbida en el mismo. 257 La idea de realizar algún tipo de medida mientras el paciente se está tratando ha sido ampliamente desarrollada a lo largo de la historia de la radioterapia, principalmente con sistemas de dosimetría in vivo basados en diodos.…”

Section: Sistemas De Verificación Durante El Tratamientounclassified

Guía para el control de calidad y seguridad de los sistemas de planificación y planes de tratamiento de radioterapia externa

García Romero,

Baeza Trujillo,

Teijeiro García

et al. 2024

Rev Fis Med

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El contenido del documento refleja las recomendaciones de la SEFM para el control de calidad y uso seguro de los sistemas de planificación de radioterapia externa. Se hace una exposición inicial de los motivos, consideraciones generales y principales novedades a tener en cuenta en los sistemas de planificación actuales, para pasar a analizar detalladamente la caracterización de las unidades de tratamiento y los parámetros que hay que tener en cuenta en el modelado de las mismas, haciendo especial hincapié en aquellos que tienen que ver con el colimador multilámina. En el documento se distinguen tres secciones diferentes que tratan de abarcar todo aquello que influye en que el producto del sistema de planificación, el plan de tratamiento, tenga la mejor calidad y seguridad asociada: control de calidad del sistema de planificación, garantía de calidad del proceso de planificación y verificación de planes de tratamiento, todo ello siempre manteniendo la visión que proporciona el análisis de riesgos asociado. El programa de control de calidad se establece en tres pasos: estado de referencia inicial, controles periódicos y controles tras actualizaciones. Añadido a esto, se analiza el proceso de planificación y cómo garantizar la calidad en el mismo por medio de procesos globales (auditorías y pruebas end-to-end), evaluación de planes y sistematización relacionada con la protocolización y las soluciones de clase. Por último, se describen las herramientas de verificación de planes y sus limitaciones, las métricas asociadas así como las estrategias de verificación posibles. Todo el documento culmina con un último capítulo que resume todas las recomendaciones basándose en lo expuesto y concreta las tolerancias a utilizar en cada etapa.

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Section: Sistemas De Verificación Durante El Tratamientounclassified

Guía para el control de calidad y seguridad de los sistemas de planificación y planes de tratamiento de radioterapia externa

García Romero,

Baeza Trujillo,

Teijeiro García

et al. 2024

Rev Fis Med

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“…Considering that the historical γ metric method cannot provide additional information about failure points 15 , reconstructed doses on CT images can achieve a more representative and comprehensive quality assurance on radiotherapy planning. A direct dosimetric comparison can be performed in regions of interest by the reconstructed and planned DVHs 4 , 5 . To date, however, how the linear interpolation affect the accuracy of the reconstructed 3D volume dose and subsequently the DVHs metrics calculation have not been evaluated, and it also remains unclear how does the linear interpolation algorithm affect the accuracy of dose reconstruction in human regions of interest with different mass densities and scattering abilities.…”

Section: Introductionmentioning

confidence: 99%

Application of a linear interpolation algorithm in radiation therapy dosimetry for 3D dose point acquisition

Yixiao

et al. 2023

Sci Rep

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Air-vented ion chambers are generally used in radiation therapy dosimetry to determine the absorbed radiation dose with superior precision. However, in ion chamber detector arrays, the number of array elements and their spacing do not provide sufficient spatial sampling, which can be overcome by interpolating measured data. Herein, we investigated the potential principle of the linear interpolation algorithm in volumetric dose reconstruction based on computed tomography images in the volumetric modulated arc therapy (VMAT) technique and evaluated how the ion chamber spacing and anatomical mass density affect the accuracy of interpolating new data points. Plane measurement doses on 83 VMAT treatment plans at different anatomical sites were acquired using Octavius 729, Octavius1500, and MatriXX ion chamber detector arrays, followed by the linear interpolation to reconstruct volumetric doses. Dosimetric differences in planning target volumes (PTVs) and organs at risk (OARs) between treatment planning system and reconstruction were evaluated by dose volume histogram metrics. The average percentage dose deviations in the mean dose (Dmean) of PTVs reconstructed by 729 and 1500 arrays ranged from 4.7 to 7.3% and from 1.5 to 2.3%, while the maximum dose (Dmax) counterparts ranged from 2.3 to 5.5% and from 1.6 to 7.6%, respectively. The average percentage dose/volume deviations of mixed PTVs and OARs in the abdomen/gastric and pelvic sites were 7.6%, 3.5%, and 7.2%, while mediastinum and lung plans showed slightly larger values of 8.7%, 5.1%, and 8.9% for 729, 1500, and MatriXX detector arrays, respectively. Our findings indicated that the smaller the spacing between neighbouring detectors and the more ion chambers present, the smaller the error in interpolating new data points. Anatomical regions with small local mass density inhomogeneity were associated with superior dose reconstruction. Given a large mass density difference in the various human anatomical structures and the characteristics of the linear interpolation algorithm, we suggest that an alternative data interpolation method should be used in radiotherapy dosimetry.

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“…The use of transmission detectors in the context of in vivo dosimetry, and in particular pixelated silicon thin-detector technologies, is still quite restricted. A recent publication provides an update on the use of a commercial silicon diode transmission dosimetry system [ 4 ] with another offering a solution in a silicon strip detector array [ 5 ]. The systems generate significant attenuation of the therapy beam, which would require correction of the treatment plan if used at the time of treatment.…”

Section: Introductionmentioning

confidence: 99%

Performance of a Full-Scale Upstream MAPS-Based Verification Device for Radiotherapy

Velthuis

Pritchard

et al. 2023

Sensors

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Intensity-modulated radiotherapy is a widely used technique for accurately targeting cancerous tumours in difficult locations using dynamically shaped beams. This is ideally accompanied by real-time independent verification. Monolithic active pixel sensors are a viable candidate for providing upstream beam monitoring during treatment. We have already demonstrated that a Monolithic Active Pixel Sensor (MAPS)-based system can fulfill all clinical requirements except for the minimum required size. Here, we report the performance of a large-scale demonstrator system consisting of a matrix of 2 × 2 sensors, which is large enough to cover almost all radiotherapy treatment fields when affixed to the shadow tray of the LINAC head. When building a matrix structure, a small dead area is inevitable. Here, we report that with a newly developed position algorithm, leaf positions can be reconstructed over the entire range with a position resolution of below ∼200 μm in the centre of the sensor, which worsens to just below 300 μm in the middle of the gap between two sensors. A leaf position resolution below 300 μm results in a dose error below 2%, which is good enough for clinical deployment.

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Delta4 Discover transmission detector: A comprehensive characterization for in-vivo VMAT monitoring

Cited by 8 publications

References 26 publications

Guía para el control de calidad y seguridad de los sistemas de planificación y planes de tratamiento de radioterapia externa

Guía para el control de calidad y seguridad de los sistemas de planificación y planes de tratamiento de radioterapia externa

Application of a linear interpolation algorithm in radiation therapy dosimetry for 3D dose point acquisition

Performance of a Full-Scale Upstream MAPS-Based Verification Device for Radiotherapy

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