Dante Amelio
Proton Therapy Center – Azienda Provinciale per I Servizi Sanitari (APSS), Italy
Title: 18F-DOPA PET for proton therapy treatment planning in high-grade gliomas
Biography
Biography: Dante Amelio
Abstract
In high-grade gliomas (HGG), treatment planning and evaluation of local response to therapy are usually based on magnetic resonance imaging (MRI) and computed tomography. Although these investigations show the anatomy of the brain with high accuracy they seem insufficient for proper tumor visualization. At the same time, recent technical advances in radiation therapy such as intensity-modulated radiation therapy and proton therapy (PT) provide the ability to deliver higher radiation doses to the most resistant tumor regions as well as reduce the dose delivered to the surrounding normal structures. Therefore, there is an urgent need for new imaging approaches to increase accuracy in tumor delineation for high precision radiotherapy. Imaging the biological and molecular characteristics of tumor tissue by positron emission tomography (PET) is an interesting approach to improve treatment planning for high precision radiotherapy as well as to evaluate tumor response after treatment. In fact, amino acid transport is generally increased in malignant transformation due to high income of the amino acid to the tissue, the intrinsic activity of the amino acid transporter and the rate of the intracellular amino acid metabolism. From this standpoint the amino acid tracer 18F-DOPA (3, 4-dihydroxy-6-[18F] fluoro-L-phenylalanine) has a high tumor-to-background signal and high sensitivity for glioma imaging. For these reasons we routinely integrate our planning with 18F-DOPA PET in patients with HGG treated with PT post-operatively or at progression/relapse (re-irradiation). 18F-DOPA PET imaging may more accurately identify regions of tumor extension and change the expected planning, as determined just by MRI, in many cases. Even though data are not definitive effective chemotherapy combined with highly conformal radiotherapy targeted to areas at highest risk for tumor recurrence may allow us to improve the therapeutic index.