Nuclear medicine imaging

By Dr. Elísio Sousa [email protected]

Dr Elísio Sousa is a Nuclear Medicine Specialist, Director of Nuclear Medicine, a component of the Unit of Cardiovascular Intervention (UCI) at the Hospital Particular do Algarve in Alvor.

Nuclear medicine is a medical specialty that uses small amounts of radioactive material (radiopharmaceuticals, so called radiotracers) to diagnose or treat a variety of diseases.

The image of a nuclear medicine exam reveals the function and structure of a specific organ, in contrast to diagnostic radiology, which is based on a static image of the anatomy or organ. Changes in the normal function and structure of cells are detected at a very early stage, long before a radiology exam can detect an abnormality.

Image of thyroid glands using nuclear medicine.
Image of thyroid glands using nuclear medicine.

Therefore, a nuclear medicine image is very important for an accurate and early diagnosis.

A nuclear image is an infallible way of obtaining medical information that may otherwise be unavailable, require surgery, or necessitate more expensive diagnostic tests.

Moreover, the amount of radiation absorbed by the patient is a lot lower than the amount of radiation normally absorbed by other radiological tests, such as conventional X–rays  or CT scans.

These two techniques (radiology and nuclear medicine) can actually complement one another, allowing for a more precise diagnosis.

Nuclear medicine can produce a fusion of images between both tests, increasing the diagnostic capacity of both.

Fusion of images obtained using nuclear medicine and radiology.
Fusion of images obtained using nuclear medicine and radiology.

Patients that need to undergo a nuclear medicine test are submitted to non-invasive and painless procedures; a radiotracer is either injected into a vein (most cases), swallowed or inhaled as a gas.

The selection of the procedure utilised depends on the nuclear test the patient needs to undergo and which particular organ needs to be studied.

Once administered, the radiopharmaceuticals which are administered to a patient needing to undergo a nuclear medicine test are distributed throughout the body and directed to a previously known area of the body, where it gives off energy in the form of gamma rays.

This energy is detected by a device called a gamma camera, which then transmits the information to a computer that measures the amount of radiotracer absorbed by the body. Special pictures are then produced giving  details on both the function as well as the structure (functional structure) of organs and tissue.

A nuclear medicine specialist can then study these diagrams and areas of interest and, by calculating biological rates, can reach a very early diagnosis of a certain pathology, long before it is revealed by any other radiology examination or test. 

Nuclear medicine also offers therapeutic procedures focusing directly on the targeted organ.

Some examples where the diagnosis of nuclear medicine can be applied are:

• Heart – evaluation of blood flow to the heart muscle; cardiac function; determination of the extent of the damage caused after a heart attack.

• Kidney – kidney function; anatomic-functional abnormalities; kidney infections.

• Bladder – reflux.

• Bone – infection; metabolic disease; orthopedic injuries (such as fractures); arthritis; tumors.

• Thyroid – thyroid function to detect an overactive or under active thyroid; cancer.

• Esophagus and Stomach – gastric empting abnormalities; gastric reflux.

• Bowel – bleeding; ectopic gastric mucosa.

• Brain – abnormalities in blood circulation and cerebral structure, such as seizures, memory loss and others diseases such as Alzheimer, Parkinson.

• Lungs – respiratory and blood flow alteration.

• Tumors – determination of the presence or spreading of cancer in various parts of the body.

• Pre-surgery – locating lymph nodes before surgery in patients with breast cancer, melanoma and other tumors.

• Infections– documents and locates their presence.

And many others clinical applications are possible, both in pediatrics as well as in adult patients. Certain pathologies are treated by nuclear medicine and include:

• Thyroid Gland – radioactive iodine (I-131) therapy is used to treat hyperthyroidism (overactive thyroid, for example, Graves’ disease) and thyroid cancer.

• Blood Disorders – radioactive phosphorus (P-32) are used to treat certain blood disorders.

• Bone Metastases – radioactive materials are used to treat painful tumor metastases to the bones.

Hospital Particular do Algarve in Alvor is the only hospital south of Lisbon, including the Algarve and Alentejo, where nuclear medicine is available either in private or public hospitals. There are not many doctors in Portugal, or in Europe, who specialise in nuclear medicine. For more information, please contact Hospital Particular do Algarve in Alvor on 282 457 516.