Comisionamiento del sistema integrado de radiocirugía Varian ICVI. / Commissioning of the integrated radiosurgery system Varian ICVI.

Galvañ, Joaquín (2017) Comisionamiento del sistema integrado de radiocirugía Varian ICVI. / Commissioning of the integrated radiosurgery system Varian ICVI. Master in Medical Physics, Universidad Nacional de Cuyo, Instituto Balseiro.

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Abstract in Spanish

La radiocirugía es una técnica de radioterapia compleja que requiere altos niveles de precisión debido a la elevada dosis entregada de forma hipofraccionada sobre un pequeño volumen rodeado por estructuras de riesgo. Para resguardar dichas estructuras y generar alto gradiente de dosis, la técnica puede ser administrada mediante colimadores cónicos, los cuales conforman campos considerados pequeños. Trabajar con dichos campos implica dificultades dosimétricas, por lo cual se han desarrollado nuevos protocolos. Se comisionó el sistema de radiocirugía ICVI de Varian, que incluye colimadores cónicos de 4 mm, 5 mm, 7,5 mm, 10 mm, 12,5 mm, 15 mm y 17,5 mm, a ser usado en un acelerador TrueBeam STx® con energías 6 MV y 10 MV, con y sin filtro aplanador. Se midieron perfiles, curvas de dosis en profundidad y output factors, tal como lo requiere el software de planificación Eclipse™ Cone Planning. Se utilizaron detectores Edge™, microDiamond™ y Diodo E™, así como el fantoma 3D Scanner™, y los resultados se compararon con los datos de referencia del fabricante. Los perfiles y curvas de dosis en profundidad calculados se validaron utilizando diferentes criterios gamma. También se realizó un estudio End-to-End con el fantoma StereoPhan™ y la cámara de ionización PinPoint® 3D. Los conos iguales o mayores a 7,5 mm mostraron concordancia dentro del 2% entre lo medido y lo calculado. Se requiere otro método de validación para los conos más chicos.

Abstract in English

Radiosurgery is a complex radiotherapy technique wich requires high levels of precision due to the high dose delivered in few fractions over a small volume surrounded by risk structures. To protect these structures and generate a high dose gradient, the technique can be administered using conical collimators, which form fields considered small. Working with these fields implies dosimetric difficulties, for which new protocols have been developed. The Varian ICVI radiosurgery system was commissioned, which includes 4 mm, 5 mm, 7.5 mm, 10 mm, 12.5 mm, 15 mm and 17.5 mm conical collimators, to be used in a TrueBeam STx® accelerator with 6 MV and 10 MV energies, both with and without flattening filter. Profiles, dose depth curves and output factors were measured, as required by the Eclipse™ Cone Planning software. Edge™, microDiamond™ and Diode E™ detectors were used, as well as the 3D Scanner™ phantom, and the results were compared with the manufacturer’s reference data. Calculated profiles and dose depth curves were validated using different gamma criteria. An End-to-End test was also carried out with the StereoPhan™ phantom and the PinPoint® 3D ionization chamber. The cones equal or greater than 7.5 mm showed concordance within 2% between the measured and the calculated. Another method of validation is required for the smaller cones.

Item Type:Thesis (Master in Medical Physics)
Additional Information:Área Temática: Radiocirugía.
Keywords:Radiosurgery; Radiocirugía; Collimators; Colimadores; [Small fields, Pequeños campos; Commissioning; Comisionamiento; TrueBeam STX; TrueBeam STX; Eclipse cone planning]
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Subjects:Medicine > Física médica
Divisions:Fundación Centro de Medicina Nuclear y Molecular de Entre Ríos
ID Code:668
Deposited By:Tamara Cárcamo
Deposited On:02 Jul 2018 16:19
Last Modified:02 Jul 2018 16:20

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