Article

Radioterapia estereotáctica

Anales del sistema sanitario de Navarra, ISSN 1137-6627, Vol. 32, Nº. 2, 2009 (Ejemplar dedicado a: La radioterapia en el siglo XXI), pags. 61-71 01/2009;
Source: OAI

ABSTRACT La radioterapia con técnica estereotáctica es una modalidad de radioterapia externa que utiliza un sistema de coordenadas tridimensionales independientes del paciente para la localización precisa de la lesión. También se caracteriza porque los haces de irradiación son altamente conformados, precisos y convergentes sobre la lesión que hacen posible la administración de dosis muy altas de radioterapia sin incrementar la irradiación de los órganos o estructuras sanas adyacentes. Cuando el procedimiento se realiza en una sesión de tratamiento se denomina radiocirugía y si se administra en varias sesiones se denomina radioterapia estereotáctica. Se precisa de sistemas de fijación e inmovilización del paciente especiales (guías o marcos estereotácticos) y dispositivos de radioterapia capaces de generar haces muy conformados (acelerador lineal, gammaknife, cyberknife, tomoterapia, ciclotrones). La radioterapia estereotáctica moderna utiliza marcas radioopacas intratumorales o sistemas de imágenes de TAC incluidos en el dispositivo de irradiación, que permiten una precisa localización de las lesiones móviles en cada sesión de tratamiento. Además, los avances tecnológicos hacen posible coordinar los movimientos de la lesión en la respiración con la unidad de radioterapia (gaiting y tracking) de forma que pueden estrecharse al máximo los márgenes y por lo tanto excluir un mayor volumen de tejido sano La radiocirugía está indicada principalmente en lesiones cerebrales benignas o malignas menores de 3-4 centímetros (malformaciones arteriovenosas, neurinomas, meningiomas, metástasis cerebrales) y la radioterapia estereotáctica se administra fundamentalmente en tumores de localización extracraneal que requieran una alta conformación y precisión como cáncer precoz de pulmón inoperable y metástasis hepáticas.

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