Titanium Screws as Fiducial Markers for Image-Guided Stereotactic Proton Irradiation in Pediatric Central Nervous System Tumors: A Technical Report

Objectives: Fiducial markers (FM) have been used to enhance the accuracy of radiation therapy in central nervous system (CNS) tumors. Recently, image-guided radiotherapy utilizing FM has been used in proton therapy of CNS tumors. We describe our surgical technique of placement of titanium screws as cranial FM in children undergoing proton therapy for CNS tumors. Methods: Records of children undergoing cranial fiducial placement for proton therapy were reviewed. Details of the adjuvant treatment of their CNS tumors were examined. Indications for placement of the FM, the technique of placement as well as the operative data and complications were reviewed. Results: Twelve children, aged 10 months to 16 years (mean: 7.6 years), underwent FM placement. When available, the patients had their proton irradiation as part of or according to Children’s Oncology Group protocols. All patients had implantations of FM onto bilateral frontal and parietal bone sites, using commercial titanium screws, in a noncollinear fashion. Ten operations were performed on an outpatient basis. There were no surgery-related complications. FM facilitated the cranial alignment for targeting of proton irradiation in all patients. Conclusions: Commercially available titanium screws can be used as FM for cranial proton radiotherapy. The procedure can be done quickly and safely on an outpatient basis. Pediatric neurosurgeons can perform this procedure on their patients at their home institutions to facilitate treatment at regional proton therapy centers.