Fractionated SRS makes it possible to administer an even higher dose of radiation to brain lesions in very few sessions, thus preserving the structure and function of neighbouring normal cells as much as possible It is performed by a dose per fraction that is incapable of causing damage to healthy tissues but which accumulates in the diseased tissues, preventing the appearance of after-effects or complications. It is mainly applied when the lesion is very close to especially critical structures such as the brain stem, optic nerves, chiasm or pituitary gland.
Each treatment session is administered with the IMRT technique in which not only the shape of the irradiation field is adapted to that of the tumour with sub-millimetric precision but also the intensity of the irradiation beam is variable in each field, adapting to the anatomical characteristics of the tumour and normal structures.
The IMOR Institute immobilises the patient using thermoplastic masks to ensure the precise position is maintained while the treatment is performed. The position is controlled using a system of infrared cameras that detect position changes of less than 1 mm and/or which exceed tenths of a second.