Molecular Imaging and Therapy

At Fred Hutch Molecular Imaging is Part of Every Patient's Care

What is Molecular Imaging?

Imaging methods like X-ray, ultrasound and computed tomography (CT) are good at showing structures inside your body. They tell us about the size, shape and position of things. This includes both normal structures, like bones and organs, and abnormal masses, like cancerous tumors.

Molecular imaging scans do something else, too. Along with making pictures of the structures, these scans give your physicians details about your body’s function, or how it is working. They allow us to measure processes in and around your cells. The results tell us about the cells’ health.

Molecular imaging and therapy uses small amounts of radioactive substances to detect or treat disease.

At Fred Hutchinson Cancer Center, our molecular imaging and therapy specialists are part of nearly every patient’s care. They do imaging scans and read them to diagnose, stage and monitor cancer. They also provide therapies to stop or reverse cancer growth.

Fred Hutch physicians use molecular imaging scans to check for cancer in many parts of the body, such as the bones, endocrine (hormone) system, liver, lungs, heart, brain and other organs.

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Molecular Imaging

How do molecular imaging scans work?

Before a molecular imaging scan, a small amount of a radioactive drug is put into your bloodstream. This is done by intravenous (IV) injection.

Radioactive drugs are drugs that are linked with radioactive elements (radionuclides). They are also called radiopharmaceuticals. When they are given in small amounts, such as for scans, they may also be called radiotracers.

The radioactive drug travels through your body and builds up in certain places. For example, it may build up in one organ or in cells that have points (receptors) on their surface where that drug can attach. Diseased cells take up the drug in a different way than healthy cells.

Given in such a small amount, the radioactive drug has no effect on your body. But the energy it gives off can be detected by a scanner. This lets your team see where the diseased cells are.

The scan is made by a machine with a special camera that detects radiation. Using data from the scanner, a computer makes a picture of the inside of your body showing where the radiation is. Then your molecular imaging specialist reviews this picture.

It is common to call places with more radiation “hot spots” or to say they “light up” on the scan. Either hot spots or cold spots may be signs of cancer or other disease.

Which scans does Fred Hutch offer?

Fred Hutch physicians use molecular imaging scans to check for cancer in many parts of the body, such as the bones, endocrine (hormone) system, liver, lungs, heart, brain and other organs.

The scan we use most often is a PET/CT (positron emission tomography/computed tomography) scan. In a PET/CT, both PET and CT scans are done. Then the two types of pictures are put together into a single set of images. This combines details about structure and function.

We also perform SPECT (single-photon emission computed tomography) scans. Usually, we do a CT scan at the same time (SPECT/CT). These scans are useful for seeing how well a tumor has taken up a radioactive drug so we know whether a patient should keep getting molecular therapy. Sometimes a SPECT/CT can tell us if tumors are responding during treatment.

Another scan we use is a planar imaging scan. A planar imaging scan is often done to:

Detect cancer in the bones. This may be called a bone scan.
Check that heart function is normal before starting treatment that might damage the heart. This is also called a multigated acquisition (MUGA) scan or radionuclide ventriculogram (RVG).

For some planar scans, we may add a SPECT/CT scan to help detect an abnormality.

What can these scans tell us?

Your physicians use molecular imaging scans to tell what is happening in your organs and tissues and how well they are working. The scans can tell your physicians things like:

If cancer cells are present (even if the tumor is too small to show up on other types of imaging)
Where tumors are and how large they are
Where cancer cells have spread beyond the main site
If the cancer will respond to certain medicines you have not had yet
How well the cancer responded to treatments you already had
If the cancer is shrinking or growing compared to earlier scans or if it has come back after it seemed to be gone

By telling us about what is happening in and around your cells, a nuclear medicine scan can give us important information. It can tell us about your health before there are structural changes that would show up on CT or magnetic resonance imaging (MRI).

“Looking at a CT scan is like looking at a light fixture to see whether there’s a bulb. A molecular imaging scan is like turning on the electricity to see whether the bulb lights up.”

— Delphine Chen, MD, Director of Molecular Imaging and Therapy

Molecular Therapies

Physicians are always working on better ways to stop cancer cells while doing the least harm to the body’s healthy cells. Molecular therapies are one of these ways. They deliver radiation directly to cancer cells using radioactive drugs.

This is an area of active research among scientists and physicians. Studies are happening right now, including at Fred Hutch, to find new options for treating many types of cancer. Fred Hutch is a leader in offering molecular therapies for neuroendocrine tumors (NETs), prostate cancer and other diseases.

How do molecular therapies work?

A radiopharmaceutical is a drug linked with a radioactive element. It is put into your bloodstream by infusion (injection). The drug travels through your body and builds up in certain places. For example, it may build up in one organ or in cells that have points (receptors) where that drug can attach. Then the drug delivers the radiation into these cells.

The key is to use a drug that binds to your type of cancer cells. The drug acts as a delivery method, taking “packages” of radiation where they are needed to treat your disease.

The radiation given for treatment is stronger than the radiation for scans. Because the goal is to kill cancer cells, larger amounts are given to damage the cells the drug binds to. This can also damage a small number of nearby cells.

Molecular therapies are more targeted than conventional chemotherapy or radiation therapy. Ideally, they work better at the level of your tumor cells with fewer side effects and less damage to your healthy cells.

Which therapies does Fred Hutch offer?

At Fred Hutch, we offer all approved molecular therapies, including these:

Lutetium-177 dotatate (Lutathera). It is used for certain neuroendocrine tumors and certain types of prostate cancer with a neuroendocrine component.
Lutetium-177 vipivotide tetraxetan (Pluvicto). This treats prostate cancer with the PSMA biomarker (prostate-specific membrane antigen) that has spread to other parts of the body.
Radium-223 dichloride (Xofigo). This is given to patients with prostate cancer that has traveled to their bones.
Yttrium-90 ibritumomab tiuxetan (Zevalin). This is used, along with the targeted therapy rituximab, for some forms of non-Hodgkin lymphoma.

Fred Hutch physicians lead and take part in studies testing new therapies or ways to improve existing therapies. This means Fred Hutch patients may have the chance to try treatment options not offered at all treatment centers.

Which cancers can these therapies treat?

For this type of treatment to work, scientists first need to find targets on cancer cells. Then they need to find or develop drugs that will seek those targets. So far, radiopharmaceuticals are approved by the U.S. Food and Drug Administration to treat a few types of cancer. These include certain neuroendocrine tumors (such as neuroendocrine tumors from the gastrointestinal system, paragangliomas and pheochromocytomas), prostate cancer that has spread to other parts of the body and non-Hodgkin lymphoma.