The role of amino acid PET in the era of checkpoint inhibitors and targeted therapy for brain tumor treatment

Purpose of review To summarize the role of diagnostic amino acid PET in the era of checkpoint inhibitors and targeted therapies for brain tumor treatment. Recent findings Amino acid PET, particularly O -(2-[ 18 F]-fluoroethyl)-L-tyrosine (FET) PET, has shown promise in distinguishing treatment-related changes such as pseudoprogression and pseudoresponse from true tumor relapse in patients receiving immunotherapy or targeted therapies for brain metastases and gliomas, often outperforming conventional MRI. Additionally, serial amino acid PET imaging has demonstrated potential in early response assessment following these agents. Summary Larger prospective trials with a higher number of patients are still needed to validate the clinical impact of amino acid PET when immunotherapy or targeted therapies are used for brain tumor therapy.