Brain metastases often occur as a result of advanced cancer and, despite medical innovations, are still associated with a poor prognosis. Now, an international expert committee led by the Medical University of Vienna and the Ludwig Maximilian University Hospital (LMU) in Munich has taken an important step towards improving diagnostics and therapy monitoring. A special imaging procedure, amino acid PET, can not only improve patient care, but also advance research into the development of new treatment approaches. The first standardised criteria for the use of this method have now been published in the top journal Nature Medicine.

Until now, magnetic resonance imaging (MRI) has been the main method used to diagnose and monitor the treatment of brain metastases. However, this method cannot visualise the metabolic activity of tumour cells. That is why amino acid positron emission tomography (amino acid PET) is increasingly being used in research, but also in the care of patients with brain metastases. This imaging technique uses radiolabelled substances to achieve a more precise assessment of tumour metabolism and thus a more accurate estimation of the tumour's response to therapy. The amino acid tracers used in this process accumulate preferentially in cancer cells and can thus detect the tumour load more accurately than conventional MRI techniques.

Targeted evaluation of treatment options
Despite its increasing use in research and clinical routine, there are still no standardised criteria for the use of amino acid PET in brain metastases. These have now been developed by an international research group, the so-called RANO group, under the leadership of oncologist Matthias Preusser from the Medical University of Vienna and nuclear medicine specialist Nathalie Albert from the Ludwig Maximilian University Hospital (LMU) in Munich. Maximilian J. Mair and Anna S. Berghoff (Clinical Division of Oncology, Department of Medicine I) from MedUni Vienna are also involved in the groundbreaking work. The criteria, entitled "PET RANO BM 1.0", define a standardised procedure for assessing the metabolic response of brain metastases to treatment for the first time. This could lead to PET imaging being more closely integrated into clinical trials in the future, in order to evaluate new therapy options in a targeted manner.

"The introduction of the new criteria is an important step towards improving diagnosis and therapy monitoring for brain metastases," says Matthias Preusser. It may also allow a more precise distinction between true tumour changes and therapy-related effects such as tissue damage after radiotherapy. "This could not only optimise patient care, but also accelerate the development of innovative treatment strategies," adds Nathalie Albert, Professor of Nuclear Medicine and Senior Physician at the Department of Nuclear Medicine at the Ludwig Maximilian University Hospital (LMU) in Munich.