Spine Stereotactic Body Radiation Therapy for a Patient With a Metallic Implant in Low-Field Magnetic Resonance-Guided Linear Accelerator: A Case Report

The rise in radiation therapy challenges facing the management of pain and neurologic symptoms from vertebral metastasis has paralleled advances in cancer treatment and patient prognosis. Surgical options include decompression to alleviate spinal cord compression symptoms, with consideration for spinal stability through fixation using titanium alloy implants. Previous studies comparing radiation alone with postoperative irradiation following decompression surgery showed superior functional outcomes. Stereotactic body radiation therapy (SBRT), which concentrates radiation on the tumor while sparing surrounding organs, has clinical advantages when combined with surgery. However, the accurate delineation of targets and organs, particularly the spinal cord of a patient with metallic implants, is difficult with computed tomography and magnetic resonance (MR) images because of metal artifacts and registration errors. The low-field MR-guided radiation therapy (the low-field MRgRT) system offers advantages in target delineation with metal artifact suppression because of its associated low-magnetic field and no need for registration between a computed tomography image and an MR image for the delineation of targets and organs because the low-field MRgRT system uses the MR image acquired by itself as the primary image. The advantages make the low-field MRgRT suitable for spine SBRT, especially for patients with metallic implants. Here, we present a case of successful postoperative spine SBRT using the low-field MRgRT, ensuring the identification of the spinal cord, and safe and accurate treatment in a patient with metallic implants. The conclusion highlights the low-field MRgRT as a viable option for postoperative spine SBRT, which is particularly beneficial for patients with metallic implants, ensuring treatment safety and accuracy.