AI Summary Nuclear imaging uses a small amount of radioactive tracer and a gamma camera to show how the liver, gallbladder, and bile ducts work. The HIDA scan checks for gallbladder or bile duct problems, the PET scan helps evaluate some liver cancers, and the liver-spleen scan assesses liver function and helps diagnose conditions. Tell your team about allergies, pregnancy, or nursing, and drink plenty of water afterward.
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Nuclear imaging shows how your body handles a tiny amount of radioactive tracer. A gamma camera picks up the signal and turns it into pictures. These scans give your care team information that a standard ultrasound, CT scan, or MRI may not show.
This page introduces the group and points you to two detailed guides: the HIDA scan, which looks at the gallbladder and bile ducts, and the PET scan, which doctors use in some liver cancer evaluations.
Below, you will find a side-by-side comparison, what to expect on scan day, safety points to raise with your team, and answers to common questions.
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Nuclear Imaging Basics
Nuclear imaging uses a very small amount of radioactive material, called a tracer. A healthcare provider injects the tracer into a vein. Your body takes it up through the bloodstream. The tracer gives off gamma rays, and a gamma camera detects them to make an image.
Most liver imaging, such as ultrasound, CT, and MRI, focuses on the size, shape, and texture of the organ. Nuclear scans add a different view. Doctors use them to assess how the liver is working, help diagnose a condition, and check whether a treatment is helping.
Two scans in this group have their own pages: the HIDA scan and the PET scan. A third test, the liver scan (also called a liver-spleen scan), uses the same technology. It looks at the liver and the spleen together, because the two organs sit close to each other and conditions that affect one often affect the other.
Nuclear imaging is one part of a liver workup. Your doctor may combine it with blood tests, other imaging, or a biopsy.
Side-by-Side Scan Comparison
Your care team chooses the scan based on your symptoms, your history, and the question they need answered.
| Scan | What it looks at | How doctors use it | Radiation and safety |
|---|---|---|---|
| HIDA scan (cholescintigraphy) | The gallbladder and bile ducts | To detect abnormal gallbladder contraction or a blocked bile duct | Uses a nontoxic radioactive tracer given by injection |
| PET scan (FDG-PET/CT) | Whole-body activity, including lymph nodes and distant organs | To look for spread of liver bile duct cancer that standard CT or MRI may miss | Uses a radioactive tracer; often paired with a CT scan |
| Liver-spleen scan | The liver and the spleen | To assess liver function, help diagnose liver conditions, and monitor treatment | Uses a very small amount of tracer; not advised during pregnancy or nursing |
Types of Nuclear Scans
A HIDA scan follows a tracer through the liver and bile ducts into the gallbladder. Doctors use it when they suspect the gallbladder is not contracting normally or a bile duct is blocked. Gallstones are one cause of these problems. An ultrasound is usually the first test for gallstones, and a HIDA scan can add information when the picture is unclear.
A PET scan detects areas where cells are unusually active. For liver cancer evaluation, doctors may pair it with a CT scan (PET/CT). Guidelines advise FDG-PET/CT for patients with intrahepatic cholangiocarcinoma that looks removable by surgery. The goal is to find lymph node or distant spread that standard CT or MRI do not show. That result can change whether surgery is the right plan. For background, see [liver cancer](/liver-diseases/liver-cancer).
The liver-spleen scan is a nuclear medicine test that looks at both organs together. Your liver and spleen absorb the tracer from the blood, and a gamma camera records the signal. Doctors use it to assess liver function, help diagnose conditions such as cirrhosis, hepatitis, cancer, abscesses, liver enlargement, and portal hypertension, and monitor how well treatment works. It does not have its own page yet.
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Scan Day Preparation
Each scan has its own instructions, so follow the ones your team gives you. These points apply to the liver-spleen scan.
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Common Questions
Yes, a liver scan is considered safe for most people. It uses a very small, mild amount of radioactive material, called a tracer, which a medical professional injects through an IV in your arm. Some people feel discomfort from the tracer. Allergic symptoms are rare, but they can happen, especially in people with latex or contrast dye allergies. Tell your doctor about any allergy before the scan. Pregnant or nursing women should not have a liver scan. If that applies to you, talk with your doctor about other options.
Usually not. Fasting and sedation are not typically needed for a liver scan. Before the scan, a doctor answers your questions. You change into a gown and remove jewelry and clothing that could get in the way. A medical professional places an IV in your arm to give the tracer. Then you lie still on a table so the images come out clear. Instructions can differ for each scan, including the HIDA and PET scans. Follow the directions your care team gives you.
The two scans look at different parts of the body and answer different questions. A HIDA scan (cholescintigraphy) follows a nontoxic radioactive tracer through the gallbladder and bile ducts. Doctors use it to find abnormal gallbladder contraction or a blocked bile duct. An ultrasound is usually the first test for gallstones, and a HIDA scan can add information. A liver-spleen scan looks at how the liver and spleen take up a tracer. Doctors use it to assess liver function, help diagnose conditions such as cirrhosis, hepatitis, cancer, abscesses, liver enlargement, and portal hypertension, and monitor how well treatment works.
Sometimes, mainly when a person has intrahepatic cholangiocarcinoma, a cancer that starts in the bile ducts inside the liver, and the tumor looks removable by surgery. Guidelines advise FDG-PET/CT in this case. The scan can find spread to lymph nodes or distant organs that standard CT or MRI do not show. It has a specificity of 97% for finding that spread. This information helps your team decide whether surgery is the right plan. Your cancer team decides whether a PET scan fits your case.
No. Pregnant or nursing women should not have a liver scan. Tell your doctor if you are pregnant, think you might be pregnant, or are nursing. Your doctor can talk with you about other options. Other imaging tests have their own cautions. For example, women who are pregnant are typically advised not to have CT scans. Always share your pregnancy status before any imaging test.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.
