Nuclear medicine: better diagnosis and therapy for brain metastases

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Brain metastases often occur as a consequence of advanced cancers. Despite medical progress, they remain associated with poor prognoses. An international research committee led by LMU University Hospital and the Medical University of Vienna has now taken an important step toward improving diagnostics and therapy monitoring. A special imaging technique called amino acid PET is capable not only of improving patient care, but also of advancing the research and development of new treatment approaches. The first standardized criteria for the use of this method have been published in the latest issue of Nature Medicine.

Before now, the primary method used for the diagnosis and therapy monitoring of brain metastases has been magnetic resonance imaging (MRI). However, this method is unable to represent the metabolic activity of tumor cells. In research, therefore, but also in the care of patients with brain metastases, so-called amino acid positron emission tomography (amino acid PET) is increasingly being used. This imaging technique employs radioactively labeled substances to obtain a more exact evaluation of the tumor metabolism and thus assess with higher precision the tumor’s response to a therapy. Because the amino acid tracers accumulate in cancer cells more than in other cells, they are able to record the tumor burden more precisely than conventional MRI techniques.

Targeted evaluation of therapy options

Despite their increased use in research and everyday clinical practice, there have been no standardized criteria for the application of amino acid PET for brain metastases before now. An international team of researchers known as the RANO group, which is led by nuclear medicine physician Nathalie Albert, Professor of Nuclear Medicine and senior physician at the Department for Nuclear Medicine at LMU University Hospital, and Prof. Matthias Preusser, head of the Division of Oncology from the Medical University of Vienna, has now laid down these criteria. Called “PET RANO BM 1.0,” these criteria lay down for the first time a standardized method for evaluating the metabolic response of brain metastases to treatment. As a result, it will be possible to integrate PET imaging more fully into clinical studies in the future in order to evaluate new therapeutic options in a targeted manner.

According to the researchers, the introduction of the new criteria is an important step for improving diagnosis and therapy monitoring for brain metastases. It will potentially also allow more precise differentiation between genuine changes in tumors and therapy-induced changes such as tissue damage after radiation. “This could not only optimize patient care, but also accelerate the development of innovative treatment strategies,” says Nathalie Albert.

Nathalie Albert et al.: RANO criteria for response assessment of brain metastases based on amino acid PET imaging. Nature Medicine 2025