gms | German Medical Science

Objective: Radiosurgical treatment of brain lesions near motor or eloquent language areas requires careful planning to achieve the optimal balance between effective dose prescription and preservation of function. Navigated transcranial magnetic stimulation (nTMS) is a novel method for exact delineation of essential versus non-essential cortical tissue.

Method: To evaluate the efficacy of nTMS data integration into the radiosurgical environment and to analyze the influence of nTMS data on the radiosurgical treatment planning, the data of 10 patients eligible for radiosurgical treatment with brain lesions in eloquent location were prospectively collected. All patients were mapped with nTMS for motor or eloquent language sites and the data was transferred to the radiosurgical planning software. The radiosurgical team classified the ease of the data transfer as well as the influence of the nTMS results on the radiosurgical treatment planning using standardized questionnaires.

Results: The integration of the nTMS data into the radiosurgical treatment planning environment was flawless and rated as easy in all cases. The influence of nTMS on the radiosurgical treatment planning was as follows: added awareness of high-risk areas in 100% of the cases, modified dose prescription in 3 cases. Radiosurgical indication and target contouring were not influenced in any of the cases by the additional nTMS information.

Conclusions: nTMS data integration into the radiosurgical workflow is feasible and influences the planning process. It may thus improve the safety for radiosurgical treatments of eloquently located lesions. Next, its impact on functional outcome and treatment efficacy has to be addressed.