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Your doctor referred you for a nuclear medicine procedure. What now? Click on the tabs below to learn more about the procedure and how it can help.

What are Nuclear Medicine and Molecular Imaging?

Molecular imaging is a type of medical imaging that provides detailed pictures of what is happening inside the body at the molecular and cellular level. Where other diagnostic imaging procedures—such as x-rays, computed tomography (CT) and ultrasound—offer pictures of physical structure, molecular imaging allows physicians to see how the body is functioning and to measure its chemical and biological processes.

Molecular imaging includes the field of nuclear medicine, which uses very small amounts of radioactive materials (radiopharmaceuticals) to diagnose and treat disease. In nuclear medicine imaging, the radiopharmaceuticals are detected by special types of cameras that work with computers to provide very precise pictures of the area of the body being imaged. Nuclear medicine can also be used to treat certain types of cancer and  other diseases.

Molecular imaging offers unique insights into the human body that enable physicians to personalize patient care. In terms of diagnosis, molecular imaging is able to:

  • provide information that is unattainable with other imaging technologies or that would require more invasive procedures such as biopsy or surgery
  • identify disease in its earliest stages and determine the exact location of a tumor, often before symptoms occur or abnormalities can be detected with other diagnostic tests

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Molecular Imaging and Brain Disorders

Brain Scan

Molecular imaging technologies play an important role in neuroimaging because they provide a ‘window’ into the living brain. Where CT and conventional MR imaging offer structural information on the brain, technologies such as PET and SPECT allow scientists to visualize brain function and to measure its chemical processes. Abnormal brain function is often detected by molecular imaging before the structural changes resulting from brain cell death can be seen on CT or MRI.

By measuring blood flow and cellular activity such as metabolism, PET and SPECT scanning are useful for: detecting the early onset of neurological disorders pinpointing areas of the brain causing epileptic seizures assisting in the diagnosis of stroke and tumors.

For example, brain cells affected by dementia are less active and have lower glucose metabolic rates than normal cells. Areas of decreased glucose metabolism may also indicate the area giving rise to seizures. Decreased oxygen use and blood flow may indicate a stroke; abnormal patterns of glucose metabolism and an accumulation of amino acid may signal the presence of a brain tumor.

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Molecular Imaging and Cancer

intense activity in the prostate cancer

Molecular imaging has become part of standard care for many types of cancer. By allowing scientists and physicians to see what is happening in the body at a cellular level, molecular imaging provides unique information to assist in the detection, diagnosis, evaluation, treatment and management of cancer. Molecular imaging is also increasingly being used for therapy, providing a means of target-specific drug delivery.

Lymphoma and esophageal, colon and lung cancer are just a few of the many types of cancer in which molecular imaging can truly change the direction and outcome of patient care. The ability of molecular imaging to detect abnormalities very early in the progression of disease has the potential to change medicine from reactive to proactive, detecting and curing disease in its most treatable phase and saving countless lives.

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Molecular Imaging and Heart Disease

Normal Myocardial Perfusion Scan

Unlike conventional imaging studies that produce primarily structural pictures, nuclear medicine and molecular imaging visualize how the body is functioning and what’s happening at the cellular and molecular levels. Cardiovascular nuclear and molecular diagnostic imaging studies enable physicians to assess the function and physiological processes of the heart, providing extremely useful information for the diagnosis, risk assessment and management of heart disease patients.

Cardiovascular nuclear medicine and molecular imaging studies are able to identify biochemical and cellular changes that occur in the earliest, most treatable stages of heart disease. These early changes provide diagnostic clues and guidance for lifestyle, medical and revascularization interventions to optimize patient outcomes.

Like the heart itself, heart disease is complex and specific to each individual. Information provided by cardiac nuclear and molecular imaging is increasingly allowing physicians to personalize treatment.

In the research laboratory, nuclear medicine and molecular imaging are also improving our understanding of cardiovascular disease and facilitating the development of new and more effective medications.

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Radioisotope Therapies

60-yr-old woman with NHL and complete response to Zevalin treatment

Molecular therapy (also called targeted radionuclide therapy or molecular radiotherapy) involves a radioactive drug compound called a radiopharmaceutical that seeks and destroys cancer cells. 

Most radiopharmaceuticals consist of a small amount of radioactive material — called a radionuclide — combined with a cell-targeting molecule. Some radionuclides have a natural ability to hone in on specific cells or biological processes and do not need to be combined or modified. When injected into the patient’s bloodstream, the radiopharmaceutical travels to and delivers radiation directly to disease sites. Because it is highly selective in its ability to damage cancerous cells while limiting radiation exposure to healthy tissue, molecular therapy is known as a targeted therapy.

Molecular therapies offer promise as a vehicle for personalized treatment of cancer, because radiopharmaceuticals may potentially be tailored to the unique biologic characteristics of the patient and the molecular properties of the tumor. In addition to the radiopharmaceuticals being used today to treat a variety of cancers — including advanced prostate cancer — researchers are working on developing and testing new radiopharmaceuticals. 

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Click here for a list of procedures that the Center of Medicare and Medicaid Services (CMS) has approved for coverage in hospitals.

Click here for a list of procedures that the Center of Medicare and Medicaid Services (CMS) has approved for coverage in private practice.

Each insurance provider has different coverage rules. The codes above are only for Medicare and Medicaid. Please contact your insurance company and reference the codes listed to get information about your plan.


Featured Resources

  • Journals

    Learn more about journals published by or sponsored by the Society of Nuclear Medicine and Molecular Imaging.

  • 2014 Patient Education Day

    For the fourth year, the SNMMI Patient Advocacy Advisory Board held a FREE Patient Program to address key topics of interest to the patient and patient advocacy community. This program provides patients with a unique opportunity to network with passionate advocates and leading experts.

  • Prostate Cancer: What’s New in Targeted Therapy and Imaging? - A Conference For Patients

    On July 26, 2014 SNMMI held a collaborative 1-day conference with PCRI and UsTOO (prostate patient advocacy groups) to educate patients about new therapies and tracers available for prostate cancer patients.


Ask Us a Question

Fill out this form to get more information about a particular procedure or event. Please note: We cannot answer any questions that pertain to your medical care. We strongly urge you to speak to your doctor about your medical concerns.

Request a Speaker

SNMMI is working to enhance relationships with relevant societies and patient organizations. We have created a pool of speakers who can speak at your next meeting. Please complete the form below to request a speaker.

Outreach Speaker Request Form
Outreach Program