Molecular Imaging Nuclear Medicine

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Swansea Nuclear Medicine Service

Nuclear Medicine - Molecular Imaging

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What is Nuclear Medicine and Molecular Imaging?

Nuclear medicine and molecular imaging allow visualization of the body’s function at cellular and molecular levels. These forms of imaging represent an evolution in diagnostic imaging from producing anatomical pictures to imaging and measuring the body’s physiological processes. It is critically important to all facets of medicine today, from diagnosing disease at its earliest stage and developing more effective therapies to personalizing medical treatment. Modern medicine is undergoing major transformations and nuclear medicine and molecular imaging are on its leading edge, probing deep inside the body to reveal its inner workings.

Nuclear medicine and molecular imaging allows scientists and healthcare providers to:

  • achieve a better understanding of the pathways of disease
  • quickly assess new drugs
  • improve the selection of therapy
  • monitor patient response to treatment
  • find new ways to identify individuals at risk for disease.

Why Are Nuclear Medicine and Molecular Imaging Unique?

In conventional diagnostic imaging, an external source of energy (such as x-rays, magnetic fields or ultrasound waves) is used to produce pictures of different tissues. In nuclear medicine and molecular imaging procedures, the energy source is introduced into the body, where it gets incorporated in a specific tissue, organ or process and is then detected by an external device (gamma camera, SPECT or PET scanners) to provide information on organ function and cellular activity.

Because disease begins with microscopic cell changes, nuclear medicine and molecular imaging have the potential to identify disease in earlier, more treatable stages, often before conventional imaging and other tests are able to reveal abnormalities. To obtain such unique information without nuclear medicine and molecular imaging tests would require more invasive procedures (such as biopsy or surgery).

How Do Nuclear Medicine and Molecular Imaging Work?

Nuclear medicine and molecular imaging involve a signal producing imaging agent (radiopharmaceutical or probe) that is introduced into the body, usually by injection, and an imaging device capable of detecting and using the probe’s signals to create detailed images. Probes, which are designed to accumulate in a specific organ or attach to certain cells, enable cell activity and biological processes to be visualized and measured.

In nuclear medicine, the imaging agent is a compound that includes a small amount of radioactive material called a radiotracer. Radiotracers (which are also called radiopharmaceuticals or radionuclides) produce a signal that can be detected by a gamma camera or a positron emission tomography (PET) scanner.

Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging

PET Imaging

PET imaging with the radiotracer FDG is one of the most significant diagnostic imaging tools ever developed. Most PET studies today are combined with computed tomography (CT) studies in order to better locate areas of abnormal cell activity.

FDG is a compound similar to glucose, or sugar, which accumulates in areas of the body that are most metabolically active (using glucose at a high rate). After FDG is injected into the patient’s bloodstream and allowed to accumulate for a short period of time, the PET scanner creates images that show the distribution of the radiotracer throughout the body, which helps determine if abnormalities are present. For example, highly active cancer cells show higher levels, or “uptake,” of FDG, whereas brain cells affected by dementia consume smaller amounts of glucose and show lower FDG uptake.

In addition to FDG, other PET radiotracers are available to visualize a large variety of cancerous and noncancerous processes.

PET is a powerful tool for diagnosing cancer and determining the severity and extent of cancer. PET scans are one of the most effective means of detecting a recurrence of disease.

PET scans are also increasingly being used to quickly assess how a patient responds to cancer treatment. In some cases, PET can determine within several days whether a therapy is working, whereas it could take months to evaluate a change in the size of the tumor with CT.

Researchers hope that information from PET studies will soon help physicians predict which patients will respond to a specific chemotherapy drug. New radiotracers are also being designed to identify biological conditions within the body (called biomarkers) that signal the presence of cancer and to capture important information on tumors that will guide physicians in selecting the most effective treatment plan.

SPECT Imaging

Single-photon emission computed tomography (SPECT) is a very significant and common imaging procedure that also involves the injection of a radiotracer into the patient’s bloodstream, where it accumulates in a target organ or attaches to specific cells. A gamma camera then rotates around the patient, collecting data to create three-dimensional images of radiotracer distribution that reveal information on blood flow and organ function. Many SPECT studies are combined with CT studies.

Are Nuclear Medicine and Molecular Imaging Safe?

Nuclear medicine and molecular imaging procedures are non-invasive and safe. Nuclear medicine diagnostic procedures use small amounts of radioactive material, sometimes about the same amount of radiation a person receives in a year of normal living or even less. As a result, the radiation risk involved in such procedures is very low compared to the potential benefits.

Nuclear medicine specialists use the ALARP principle (As Low As Reasonably Practicable) to carefully select the amount of radiotracer that will provide an accurate test with the least amount of radiation exposure to the patient. The actual dosage is determined by the patient’s body weight, the reason for the study, and the body organ being imaged. In addition, newer imaging technologies are constantly emerging to reduce radiation exposure to patients while maintaining the diagnostic accuracy of the test.

Nuclear medicine procedures have been performed for more than 50 years on adults and for more than 40 years on infants and children of all ages without any known adverse effects.

Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging

Hybrid Imaging

The combination of two imaging techniques called co-registration, fusion imaging or hybrid imaging, allows information from two different types of scans to be viewed in a single set of images. PET/CT and SPECT/CT, a combination of PET or SPECT and CT, have become standard diagnostic tools because they provide detail on both the anatomy and the function of organs and tissues.

New forms of hybrid imaging are in use or in development, including PET/MR, PET/ultrasound, and various optical technologies fused with conventional imaging techniques.

Imaging Biomarkers

Imaging biomarkers are any substances, structures, or processes that can be measured in the body (or in its products) and influence or predict the incidence of outcome or disease and that can be revealed on images. Molecular imaging biomarkers are currently being developed with the aim of helping physicians tailor the treatment plan to individuals and their individual disease patterns and quickly assess the effectiveness of the therapy. In the future, scientists hope these biomarkers will also help detect disease and identify at-risk patients.

Elevated glucose metabolism—a possible warning sign of a tumor or other abnormal cellular function—is an example of a molecular imaging biomarker currently used by physicians.

Personalized Treatment

Nuclear medicine and molecular imaging are on the forefront of the trend toward personalized treatment of cancer and heart disease. In personalized care, treatment is individualized on the basis of specific biochemical markers found in the patient and characteristics of his or her individual disease. The goal is to identify patients for particular therapies and optimize patient response to treatment while minimizing side effects.

Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging

PET/CT-Swansea Mobile Scanning Unit

The mobile Positron Emission Tomography – Computed Tomography (located outside Crush Hall at Singleton Hospital on Thursdays/Fridays) will provide PET/CT scanning for Swansea Bay and Hywel Dda University Health Boards. The service will also be available to some patients from within the Cwm Taf Morgannwg University Health Board area. more information can be found here.


Gwybodaeth i Gleifion & Lawrlwythiadau

Beth yw Sgan Esgyrn Isotop? W.NM.PL.012r4_CYM

Sgan Esgyrn - Holiadur Cyflym W.NM.PL.013r3_CYM

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Patient Information & Downloads

What is an Isotope Bone Scan? W.NM.PL.012r4

Bone Scan - Quick Questionnaire W.NM.PL.013r3

What is a MUGA scan? W.NM.PL.015r3

What is an Myocardial Perfusion (Heart) Scan? W.NM.PL.016r3

Myocardial Perfusion (Heart) Rest Scan? W.NM.PL.017r3

Patient Instructions W.NM.PL.018r3

Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging
Swansea Nuclear Medicine - Molecular Imaging