Prostate Specific Membrane Antigen Positron Emission Tomography in Management of Vestibular Schwannoma.

Vestibular schwannomas (VSs) are benign tumors arising from vestibulocochlear nerve Schwann cells. Single or multifractional stereotactic radiation therapy (SRT) is commonly used for treatment of these tumors, and accurate target delineation is critical for the focused radiation delivery, maximizing tumor control while minimizing toxicity. Contrast-enhanced magnetic resonance imaging (MRI) is the gold standard for diagnosis, monitoring of VS and is critical in precise target delineation for SRT planning. Prostate specific membrane antigen (PSMA) positron emission tomography (PET) has established clinical utility for diagnosis and monitoring of prostate cancer. However, other central nervous system neoplasms, including VS, have also been found to be PSMA tracer avid. We present the first clinical use of PSMA PET for SRT in a patient with VS who was unable to undergo MRI.