Rosa Morabito, Giovanni Grasso, Valeria Barresi, Paolo La Spina, Giada Garufi, Elisabetta Alafaci, Francesco M. Salpietro, Marcello Longo, Francesca Granata and Concetta Alafaci
Alfredo Conti, Antonio Pontoriero, Ignazio Salamone, Carmelo Siragusa, Federica Midili, Domenico La Torre, Amedeo Calisto, Francesca Granata, Pantaleo Romanelli, Costantino De Renzis and Francesco Tomasello
Symptomatic edema is a potential complication of meningioma radiosurgery. Parasagittal meningiomas are at a particular risk for symptomatic edema, suggesting a role for a venous occlusive complication. The authors sought to develop a strategy to optimize CyberKnife stereotactic radiosurgical treatment parameters to reduce the irradiation of the peritumoral venous system. Multislice CT venography with 3D reconstructions was performed and coregistered with thin-section, contrast-enhanced, volumetric MR images. The tumor and critical volumes were contoured on the MR images. Venous anatomical details obtained from the CT venographic study were then exported onto the MR imaging and fused MR imaging-CT study. Target and critical structure volumes and dosimetric parameters obtained with this method were analyzed. The authors found that reducing the irradiation of veins that course along the surface of the meningioma, which may be at risk for radiation-induced occlusion, is feasible in parasagittal meningioma radiosurgery without compromising other treatment parameters including conformality, homogeneity, and target coverage. Long-term follow-up is needed to assess the clinical validity of this treatment strategy.
Alfredo Conti, Antonio Pontoriero, Giuseppe K. Ricciardi, Francesca Granata, Sergio Vinci, Filippo F. Angileri, Stefano Pergolizzi, Concetta Alafaci, Vincenzo Rizzo, Angelo Quartarone, Antonino Germanò, Roberto Israel Foroni, Costantino De Renzis and Francesco Tomasello
The integration of state-of-the-art neuroimaging into treatment planning may increase the therapeutic potential of stereotactic radiosurgery. Functional neuroimaging, including functional MRI, navigated brain stimulation, and diffusion tensor imaging–based tractography, may guide the orientation of radiation beams to decrease the dose to critical cortical and subcortical areas. The authors describe their method of integrating functional neuroimaging technology into radiosurgical treatment planning using the CyberKnife radiosurgery system.
The records of all patients who had undergone radiosurgery for brain lesions at the CyberKnife Center of the University of Messina, Italy, between July 2010 and July 2012 were analyzed. Among patients with brain lesions in critical areas, treatment planning with the integration of functional neuroimaging was performed in 25 patients. Morphological and functional imaging data sets were coregistered using the Multiplan dedicated treatment planning system. Treatment planning was initially based on morphological data; radiation dose distribution was then corrected in relation to the functionally relevant cortical and subcortical areas. The change in radiation dose distribution was then calculated.
The data sets could be easily and reliably integrated into the Cyberknife treatment planning. Using an inverse planning algorithm, the authors achieved an average 17% reduction in the radiation dose to functional areas. Further gain in terms of dose sparing compromised other important treatment parameters, including target coverage, conformality index, and number of monitor units. No neurological deficit due to radiation was recorded at the short-term follow-up.
Radiosurgery treatments rely on the quality of neuroimaging. The integration of functional data allows a reduction in radiation doses to functional organs at risk, including critical cortical areas, subcortical tracts, and vascular structures. The relative simplicity of integrating functional neuroimaging into radiosurgery warrants further research to implement, standardize, and identify the limits of this procedure.