The role of amino acid PET in radiotherapy target volume delineation for adult-type diffuse gliomas: A review of the literature

Purpose

To summarise existing literature examining amino acid positron emission tomography (AA-PET) for radiotherapy target volume delineation in patients with gliomas.

Methods

Systematic search of MEDLINE and EMBASE databases.

Results

Twenty studies met inclusion criteria. Studies comparing MRI- and AA-PET- derived target volumes consistently found these to be complementary. Across studies, AA-PET was a strong predictor of the site of subsequent relapse. In studies examining AA-PET-guided radiotherapy at standard doses, including one study using reduced margins, survival outcomes were similar to historical cohorts whose volumes were generated using MRI alone. Four prospective single-arm trials examining AA-PET-guided dose-escalated radiotherapy reported mixed results. The two trials that used both a higher biologically-effective dose and boost-volumes defined using both MRI and AA-PET reported promising outcomes.

Conclusion

AA-PET is a promising complementary tool to MRI for radiotherapy target volume delineation, with potential benefits requiring further validation including margin reduction and facilitation of dose-escalation.