Brain metastasis (BrM) develops in approximately 40% of cancer patients. Stereotactic
radiosurgery (SRS) is a form of radiotherapy that delivers high-dose per fraction to
individual lesions that is commonly used to treat BrM.
Radionecrosis (RN) is an adverse event that occurs in approximately 10 - 25% of patients
6 - 24 months after treatment with SRS. Tumour progression may also occur due to local
failure of treatment. Radionecrosis and tumour progression share very similar clinical
features including vomiting, nausea, and focal neurologic findings.
Radionecrosis and tumour progression also share overlapping imaging characteristics. Due
to their similarities, physicians need to perform a surgical resection to diagnose the
complication. By using a hybrid FLT-PET/MRI scan, the investigators propose that this
combination scan will provide robust data with which to differentiate between
radionecrosis and tumour progression without the need for surgery. The investigators plan
to conduct a single center feasibility study to investigate the potential in
differentiating between SRS and tumour progression in patients, including those who may
have previously undergone SRS for BrM, who are suspected to have either RN or tumour
progression using hybrid FLT-PET/MRI imaging.
