Featured Case Studies 2005, Volume 2, Number 2
John Breneman, MD, Michael Lamba, PhD, and Ronald Warnick, MD
An 8-year-old boy had a growing disseminated medulloblastoma in the left frontal lobe despite multiple therapies (i.e., surgery, craniospinal radiotherapy, high dose chemotherapy with stem cell rescue). When the patient was referred to our center, MR scans showed stable disease in the posterior fossa but a progressing lesion (1.8 cm diameter) in the left frontal lobe. The boy was asymptomatic and showed no focal neurological deficits. Frameless stereotactic radiosurgery was recommended to provide local control of the single progressive lesion in this young patient, thus avoiding use of general anesthesia that is required to place a stereotactic frame.
The Five days before treatment, the patient underwent imaging studies for stereotactic localization. The CT images transferred to the BrainLAB Novalis® workstation and fused with MR scans. After contouring the lesion in axial and coronal views, we developed a treatment plan using a dynamic conformal arc technique in which the shape of the treatment beam was continuously modified to match the shape of the tumor profile (Figure 1). Returning for treatment, the patient was placed in the unique mesh mask and aligned with the template laser-localization system (Figure 2). Stereoscopic x-rays for image-guided localization were fused with the digitally reconstructed radiograph from the planning CT. A dose of 14 Gy was delivered over 20 minutes. Patient position was monitored in real time by infrared markers placed on the patient’s head. Total time on the table, including alignment, was ~30 minutes. The boy was discharged to home immediately after treatment and experienced no acute complications.
SRS In our initial experience, frameless radiosurgery using the BrainLAB Novalis® system is a practical, effective alternative to frame-based radiosurgery. Use of a head frame for radiosurgery can be especially problematic for children because general anesthesia is needed to place the frame. Compared with frame-based techniques, the BrainLAB frameless technique is equal in accuracy and offers several important advantages (e.g., elimination of discomfort associated with frame-based procedures, opportunity for upfront planning before treatment, shortened times in the treatment facility). We continue to refine and expand our use of this proton beam technology.
- Kamath R, Ryken TC, Meeks SL, et al. Initial clinical experience with frameless radiosurgery for patients with intracranial metastases. Int J Radiat Oncol Biol Phys 61(5):1467-1472, 2005.
Because of the specific nature and complexity of the services we provide, patients must have a consultation with one of our physicians prior to being referred to the center. To schedule an appointment with one of our physicians, please contact Precision Radiotherapy at 513-475-7777.