Repositioning accuracy with the Laitinen frame for fractionated stereotactic radiation therapy in adult and pediatric brain tumors: preliminary report.

PURPOSE: To determine the repositioning accuracy, patient tolerance, and clinical efficacy of stereotactic radiation therapy for brain tumors in children and adults performed with the Laitinen stereotactic localizer and head holder.
MATERIALS AND METHODS: In this retrospective analysis, stereotactic frame tolerance was assessed by recording patient discomfort or pain in the ear and nose during each treatment in 34 patients, including 21 children and 13 adults with 37 lesions treated with fractionated stereotactic radiation therapy. Radiation doses ranged from 10-60 Gy at 1.0-4.0 Gy per fraction. Repositioning accuracy was assessed by comparing portal radiographs with setup fields on computed tomographic (CT) scout images. Clinical efficacy was assessed by analyzing posttreatment CT and magnetic resonance images.
RESULTS: The stereotactic localizer was well tolerated. The mean isocenter shifts observed after studying 305 portal radiographs were x-coordinate shift of 1.0 mm +/- 0.7 (SD), y-coordinate shift of 0.8 mm +/- 0.8, and z-coordinate shift of 1.7 mm +/- 1.0. At a median follow-up of 16 months, local control was achieved in 18 of 22 primary and in one of eight of recurrent tumors.
CONCLUSION: The Laitinen stereotactic localizer is well tolerated with accurate reproducibility during stereotactic radiation therapy. Preliminary local control rates are consistent with those in other reports.