Brain PET Scans Become Mandatory Requirement for New Alzheimer’s Treatments

As the European Association of Nuclear Medicine (EANM) 2026 Annual Congress opens in Vienna, the role of brain PET imaging has shifted from a specialized research tool to an essential clinical gatekeeper. For patients seeking access to the new generation of disease-modifying Alzheimer’s therapies, these scans are no longer optional diagnostic luxuries but mandatory requirements for treatment eligibility and monitoring.

The EANM 2026 Congress, held from October 17–21, highlights a pivotal moment in neurology where nuclear medicine determines which patients are likely to benefit from anti-amyloid treatments such as Kisunla (donanemab) and Leqembi (lecanemab). Clinical guidelines now emphasize that amyloid PET imaging is required to confirm the presence of beta-amyloid plaques before these therapies can be initiated. Without visual confirmation of the drug’s target within the brain, patients cannot be prescribed these high-cost infusions.

Tau PET imaging allows clinicians to stage disease severity by mapping the distribution of neurofibrillary tangles.

The Rise of Tau PET for Disease Staging

While amyloid PET scans act as a “rule-in” tool to identify the presence of pathology, tau PET imaging has emerged as the primary method for staging the severity of the disease. While amyloid plaques often appear years before symptoms, the accumulation of tau tangles more closely correlates with actual cognitive decline. By mapping the spatial distribution of these tangles, clinicians can predict the rate of a patient’s future progression and determine if they are in the optimal “window” for treatment.

This staging capability was bolstered in October 2026 by the FDA approval of Tauklarify (MK-6240), a second-generation tau-PET tracer. This tool allows for more precise visualization of neurofibrillary tangles, providing a clearer picture of the disease’s topographical spread across the brain. For many clinical protocols, tau levels now dictate the duration of treatment, with some therapies being paused or adjusted once a specific reduction in pathology is achieved.

Improving Patient Access and Triage

The transition of PET imaging into routine clinical care has been supported by significant changes in the healthcare landscape. Previously, the high cost of radiopharmaceuticals often limited their use to academic research settings. However, recent moves by the Centers for Medicare & Medicaid Services (CMS) to unbundle payments for diagnostic radiopharmaceuticals have increased the financial viability for community hospitals and imaging centers to offer these specialized scans.

The diagnostic pathway is also becoming more streamlined through what specialists call the “plasma pivot.” Emerging blood-based biomarkers, particularly p-tau217 tests, are increasingly used as a first-line triage tool in primary care. While these blood tests can identify signs of Alzheimer’s with high accuracy, they currently serve to identify which patients should be referred for definitive PET imaging. The PET scan remains the gold standard for visualizing the actual load and location of pathology, which is critical for both initial dosing and safety monitoring during treatment.

At the Vienna congress, experts noted that the integration of these technologies—blood tests for screening, amyloid PET for selection, and tau PET for staging—represents a fundamental change in how Alzheimer’s is managed. This multi-modal approach ensures that the new class of disease-modifying drugs is targeted toward the specific biological profile of each patient, maximizing the potential for slowing cognitive decline while managing the risks associated with these therapies.

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