Image-Guided Stereotactic Radiosurgery for Spinal PathologyTumors of the Central Nervous System, Volume 12

Radiosurgery is the delivery, in a single or a few fractions, of a concentrated dose of radiation to diseased tissue with a steep dose fall-off outside the treatment volume. Traditionally, radiosurgery is delivered to intracranial targets using a rigid frame to immobilize the target and provide external reference points for target localization. The development of image-guided radiosurgery has allowed the principles of radiosurgery to be applied to the treatment of extracranial pathologies including spinal lesions. Image guidance is the use of imaging to locate the tumor before and during a treatment session and redirect the radiation source or reposition the patient based on these measurements. In this manner dose delivery accuracy comparable to frame-based radiosurgery can be achieved. Furthermore, frameless stereotactic radiosurgery allows treatments to be delivered in more than one fraction, which has the potential to reduce toxicity to healthy tissue and organs at risk such as the spinal cord, an organ that is among the most sensitive to radiation. Spinal radiosurgery has resulted in excellent rates of tumor control with a relatively low risk of radiation-induced myelopathy. Here we review currently available image-guided stereotactic radiosurgery devices that can be used to treat the spine, summarize clinical data showing the efficacy of these systems, and discuss dose and volume limits to avoid radiation toxicity induced by spinal radiosurgery for malignant and benign pathologies.