Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer. It begins in the kidney’s filtering cells and gets its name from the appearance of the cancer cells under a microscope. Like other cancers, ccRCC can spread to lymph nodes or distant organs. Knowing where the cancer is—and how far it has spread—can help doctors plan treatment.

A new imaging method designed to detect a protein often found on ccRCC cells identified more cancerous lesions than a commonly used PET scan in a small study. The findings, presented at the 2026 European Association of Nuclear Medicine Congress, suggest the scan could improve disease mapping for some patients. It has not yet been shown to help people live longer.

How the scan works

The experimental scan uses a tracer called [⁶⁸Ga]Ga-DPI-4452. It is designed to attach to carbonic anhydrase IX, or CAIX, a protein found in most clear cell kidney cancers and at low levels in normal kidney tissue.

This differs from an FDG PET scan, which uses a radioactive form of sugar to highlight areas with high glucose use. Because some healthy tissues also use a lot of glucose, FDG scans can have difficulty distinguishing certain tumors from surrounding tissue.

In the study, 68 people with kidney cancer received both scans within a week. Fifty-six had clear cell disease. The group included people with newly diagnosed tumors, people being monitored or treated, and people being evaluated for possible recurrence or spread.

Across 492 confirmed cancerous lesions, the CAIX scan detected 90.9%, compared with 56.7% for FDG PET. Among participants with ccRCC, it detected nearly 98% of lesions, compared with 47% for FDG. It also performed better at detecting whether an individual with ccRCC had disease visible on the scan.

These figures describe how often each scan detected known cancer in this study. They do not mean that the CAIX scan is equally accurate for every person or every type of kidney cancer.

Did the scan affect treatment decisions?

The researchers reported that scan findings changed disease staging or clinical management for 21 of the 68 participants. FDG PET findings led to such changes for four participants. Among those with ccRCC, the reported proportions were 37.5% with CAIX PET and 1.8% with FDG PET.

The CAIX scan identified disease not seen on the other scan in some participants, including lymph-node or distant spread. In three cases, it helped researchers question suspicious FDG findings that were later considered false positives—potentially helping avoid unnecessary procedures.

For eight people whose cancer appeared to be limited to a few sites, the CAIX scan showed more extensive disease. That information could affect whether a doctor considers local treatments, such as surgery or targeted radiation, or treatment that works throughout the body. The study did not establish which treatment is best in those situations.

The new scan also appeared better at showing brain metastases in this group. The researchers reported that it detected all 16 known brain lesions, while FDG PET detected three. This difference may be important because high FDG uptake in healthy brain tissue can make some tumors harder to see.

What the results do—and do not—show

The study was relatively small, and it did not compare the CAIX scan directly with CT or MRI. Those imaging methods remain important in kidney-cancer care. Not every suspected metastatic lesion could be confirmed by biopsy, and the scan did not perform as well for some non-clear-cell kidney cancers or for liver lesions in the full study group.

Most importantly, better detection does not automatically translate into better health outcomes. Lead author Esra Arslan, M.D., cautioned that the study assessed imaging and staging, not whether the scan improves survival.

The tracer is a smaller, peptide-based molecule. According to the researchers, it allows imaging about an hour after injection, whereas some antibody-based tracers require a wait of several days. Whether the newer approach is practical and beneficial in routine care will require further study.

A possible path toward targeted treatment

Researchers are also exploring whether CAIX could be used not only to locate tumors but to deliver radiation to them. In this approach, a CAIX-targeting compound could be paired with a radioactive substance: one version for imaging and another for treatment. This is known as theranostics—using related tools to identify a target and then treat it.

The concept is promising, but CAIX-directed treatment has not yet been shown to benefit patients. Researchers still need to study its safety, whether scan results can predict who will respond, and whether treatment improves outcomes.

The findings provide a reason to continue evaluating CAIX imaging in larger studies. For now, it is an investigational approach—not a replacement for established imaging, and not proof that detecting more lesions will extend patients’ lives.