The standard PET scan uses a radioactive form of sugar, called FDG, and lights up cells that burn a lot of sugar, as many cancers do. It is a powerful test, but it misses some cancers, including many slow-growing tumors, lobular breast cancer, prostate cancer, neuroendocrine tumors and some stomach cancers, and it also lights up inflammation. A new generation of targeted PET scans uses tracers that bind to specific features of cancer, showing what standard scans cannot. This article explains the most important ones.
The FES Scan: Seeing Estrogen Receptors Throughout the Body
The FES PET scan uses a radioactive form of estrogen that binds to estrogen receptors. It shows, in a single scan, whether each tumor in the body still carries estrogen receptors, which a biopsy of one spot cannot do. It was approved in the United States in 2020 for people with recurrent or metastatic estrogen receptor-positive breast cancer.1
Research from the Netherlands. The University Medical Center Groningen has led much of the research on FES PET. In its study of women newly diagnosed with metastatic breast cancer, the scan showed that in some women, certain tumors had estrogen receptors and others did not, information that changes treatment choices.2 Earlier research found that when tumors take up little FES, hormone therapy is unlikely to work, so other treatments can be chosen sooner.3 FES is especially useful in lobular breast cancer, which standard PET often misses. See our articles on hormone receptor-positive breast cancer and stage 4 breast cancer.
The FAPI Scan: Invented in Heidelberg
Most cancers are surrounded by connective tissue cells called cancer-associated fibroblasts, which carry a protein called fibroblast activation protein, or FAP. Researchers at Heidelberg University Hospital in Germany developed FAPI tracers that bind to this protein, and showed that they light up 28 different kinds of cancer.4 In a Chinese study at Xiamen University comparing FAPI with standard PET, FAPI found more primary tumors, lymph nodes and metastases, especially in stomach, liver and pancreatic cancer and in spread to the lining of the abdomen.5 FAPI scans do not require fasting and show the brain and liver clearly. They are available at centers in Germany, China and elsewhere, and through clinical trials in the United States. See our article on the tumor microenvironment.
PSMA and DOTATATE Scans
PSMA PET binds to a protein on prostate cancer cells and finds prostate cancer far earlier than standard scans, even when the PSA is low. See our article on prostate cancer.
DOTATATE PET binds to somatostatin receptors on neuroendocrine tumors and finds them throughout the body. See our article on neuroendocrine tumors.
See It, Treat It: Theranostics
When a scan shows that tumors carry a target, the same targeting molecule can carry radiation directly to them. This approach, called theranostics, is already used with Lutathera for neuroendocrine tumors and Pluvicto for prostate cancer, and radioactive treatments that target FAP are being tested in Germany and elsewhere.
Which scan may help depends on your type of cancer, your earlier scan results and your treatment plan. In a consultation, Dr. Silver, MD, educates you on these tests and the research behind them. Request a consultation.
How Cancer Expert MD Helps
Cancer Expert MD provides education and consultation for people with every type and stage of cancer, and specializes in Stage IV and metastatic cancer. Our book, The New Reality of Cancer, covers advanced testing from around the world. See also our articles on ctDNA liquid biopsy and tumor DNA and RNA sequencing.
Frequently Asked Questions
What is an FES PET scan?
A PET scan using a radioactive form of estrogen that shows whether tumors throughout the body carry estrogen receptors. It is used in estrogen receptor-positive breast cancer.
What is a FAPI scan?
A PET scan developed in Heidelberg, Germany, that lights up the connective tissue cells surrounding most cancers. It can find cancers that standard PET misses, especially stomach, liver and pancreatic cancers.
Why can a standard PET scan miss cancer?
Standard PET detects sugar uptake. Slow-growing tumors, lobular breast cancer, prostate cancer, neuroendocrine tumors and some stomach cancers use less sugar and can be missed.
What is theranostics?
Using the same targeting molecule first to find tumors on a scan and then to carry radiation directly to them, as with Lutathera and Pluvicto.
About the author. Dr. Silver, MD, graduated from Temple University School of Medicine, trained as an interventional cardiologist, and has practiced medicine for nearly fifty years. A lymphoma survivor of about twenty-five years, he is co-author, with Dr. Lindmeier, DHSc, of The New Reality of Cancer: The Science of Recovery. Read more about Dr. Silver, MD.
Research by Dr. Lindmeier, DHSc, cancer educator and co-author of The New Reality of Cancer.
This article is for general education only and is not individual medical advice. Always consult your own doctor before making any changes to your care.
© 2026 Lovely LYF LLC. All rights reserved. This article draws on the research in The New Reality of Cancer and may not be copied, republished or distributed without written permission.
For more in-depth information on this topic and many others, get our book, The New Reality of Cancer: The Science of Recovery.
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References
- US Food and Drug Administration. Approval of Cerianna (fluoroestradiol F 18) for PET imaging of estrogen receptor-positive lesions in recurrent or metastatic breast cancer. 2020.
- van Geel JJL, Boers J, Elias SG, et al. Clinical validity of 16α-[18F]fluoro-17β-estradiol positron emission tomography/computed tomography to assess estrogen receptor status in newly diagnosed metastatic breast cancer. Journal of Clinical Oncology. 2022;40(31):3642–3652.
- Linden HM, Stekhova SA, Link JM, et al. Quantitative fluoroestradiol positron emission tomography imaging predicts response to endocrine treatment in breast cancer. Journal of Clinical Oncology. 2006;24(18):2793–2799.
- Kratochwil C, Flechsig P, Lindner T, et al. 68Ga-FAPI PET/CT: tracer uptake in 28 different kinds of cancer. Journal of Nuclear Medicine. 2019;60(6):801–805.
- Chen H, Pang Y, Wu J, et al. Comparison of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer. European Journal of Nuclear Medicine and Molecular Imaging. 2020;47(8):1820–1832.
This article is for education only. It is not medical advice and does not diagnose or treat any condition. Cancer Expert MD has no financial relationship with any laboratory, drug maker, supplement company, clinic or hospital.
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