SURG-24
APPLICATION OF NANOTHERM^® BY STEREOTACTIC GUIDANCE: A TECHNICAL NOTE

BACKGROUND: The induction of local hyperthermia has been reported as adjuvant treatment option for malignant (recurrent) glioma. One described method uses fluid magnetic nanoparticles (NanoTherm^®) being injected into the tumor and activated by an external magnetic field. To induce therapeutically relevant hyperthermia within the target tissue the following parameters have to be considered: (i) specific absorption rate of nanoparticles, (ii) estimated blood perfusion and (iii) distribution of the nanoparticles within the treatment volume (TV). Thus the precision of instillation of the nanoparticles is crucial. However, a standardized instillation method is not available and reported results for navigated or “free hand” installation procedures are heterogeneous with regard to precision of instillation. Here we report about a stereotactically guided instillation method. METHODS: A 55-year-old female presented with a distant recurrence of glioblastoma multiforme on the contralateral hemisphere after multimodal treatment 18 months after initial diagnosis. For treatment of this circumscribed tumor we used the brachytherapy module of our stereotactic planning software (STP35) to define the TV, to calculate the required volume of NanoTherm^® (112 mg/mL Fe) and its distribution within the TV. Then several small depots of NanoTherm^® were instillated in pre-defined distances by stereotactic guidance and documented by postoperative CT. Finally hyperthermia planning was performed with the software NanoPlan^®. RESULTS: Tumor volume was 14.3ml and 5ml NanoTherm^® portioned in seven depots were necessary to cover the TV. Post-operative CT showed planned distribution of NanoTherm^® in the TV. The coverage of TV at >39°C was 98.2%. There was no procedure related complication. CONCLUSION: A stereotactic planning software might be useful for the adequate calculation of the TV, the volume and distribution of NanoTherm^® within the TV. Stereotactic guidance provides then a precise and safe installation of NanoTherm^® for the induction of local hyperthermia.