What is a nuclear medicine scan?
Generally speaking, nuclear medicine scans are considered as branch of medical imaging that uses small amounts of radioactive material to diagnose and determine the severity of or to treat a variety of diseases, including many types of cancers, heart disease, gastrointestinal, endocrine, neurological disorders and other abnormalities within the body.
On the whole, this test produces pictures (scans) of internal body parts using small amounts of radioactive material. Moreover, these scans are noninvasive and, with the exception of intravenous injections, are usually painless medical tests that help physicians diagnose and evaluate medical conditions. To sum up, these imaging scans use radioactive materials called radiopharmaceuticals or radiotracers.
When is the Nuclear Medicine useful?
Because of the special materials and equipment requirement, these scans are normally complete in the radiology or nuclear medicine department of a hospital. In fact, this test is use to provide images of organs and areas of the body that cannot be seen well with standard X-rays.
However, nuclear medicine scans use a special camera (gamma) to take pictures of tissues and organs in the body after a radioactive tracer (radionuclide or radioisotope) is put in a vein in the arm and is absorb by the tissues and organs. In general, the radioactive tracer shows the activity and function of the tissues or organs.
Additionally, in many centers, nuclear medicine images can be superimposed with computed tomography (CT) or magnetic resonance imaging (MRI) to produce special images, a practice known as image fusion.
Furthermore, these views allow the information from two different exams to be correlated and interpreted on one image, leading to more precise information and accurate diagnoses. In addition, manufacturers are now making single photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT) machines that are able to perform both imaging exams at the same time.
Nuclear medicine scans can help doctors find tumours and see how much the cancer has spread in the body also name as the cancer’s stage. These can also be use to decide if treatment is working. Generally speaking, these tests are painless and are complete through as outpatient procedure. But, the specific type of nuclear scan you’ll have depends on which organ the doctor wants to look into. In fact, the doses of radiation are very small, and the radionuclides have a low risk of being toxic or causing an allergic reaction. In conclusion nuclear scans are safe tests.
What do the nuclear scan show?
(Image Credits – shutterstock.com)
Nuclear scans make pictures based on the body’s chemistry like metabolism. These scans use liquid substances called radionuclides or tracers that release low levels of radiation.
Body tissues affected by certain diseases, such as cancer, may absorb more or less of the tracer than normal tissues. In fact, special cameras pick up the pattern of radioactivity to create pictures that show where the tracer travels and where it collects. However if cancer is present, the tumour may show up on the picture as a “hot spot” – an area of increased cell activity and tracer uptake. Depending on the type of scan done, the tumour might substitute to be a “cold spot” – a site of decrease uptake and less cell activity.
All things considered, nuclear scans may not find very small tumors, and cannot always tell whether a tumor is really cancer. These scans can show some internal organ and tissue problems better than other imaging tests, but they don’t provide very detailed images on their own. Because of this, they are often used along with other imaging tests to give a more complete picture. Some nuclear scans are also used to measure heart function.
How do the nuclear scans work?
In most cases a tracer or radionuclide that sends out small doses of radiation are given. Some are swallowed while others are put into a vein or inhale as a gas. Over time, the tracer collects in the part of the body . However, this can take from a few seconds to several days. A collect tracer sends out gamma rays that are picked by a special camera which is process by a computer, which turns them into 2- or 3-dimensional (3-D) pictures and the interpretion is done by a specialist.
Nuclear medicine scans for cancer are:
Bone scans look for cancers that may have spread metastasis from other places to the bones. They can often find bone changes much earlier than regular x-rays. The tracer collects in the bone over a few hours, then the scans are schedule.
PET (positron emission tomography) scans:
PET scans usually use a form of radioactive sugar. Body cells take in different amounts of the sugar, depending on how fast they are growing. Cancer cells, which grow quickly, are more likely to take up larger amounts of the sugar than normal cells. PET/CT scanners give information on areas of increased cell activity (from the PET), as well as show more detail in these areas.
(Image Credits – shutterstock.com)
Radioactive iodine-123 or 131 is given orally. It goes onto the blood stream and collects in the thyroid gland. This scan can be use to find thyroid cancers. Radioactive iodine can also be use to treat thyroid cancer.
MUGA (multigated acquisition) scans:
In general, this scan looks at heart function. It may be used to check heart function before, during, and after certain type of chemotherapy. Hence, the doctor may switch you to a different kind of chemotherapy depending on the report. The scanner shows how the heart moves the blood as it carries the tracer, which binds to red blood cells. The test tells the ejection fraction.
Gallium-67 is the tracer use in this test to look for cancer in certain organs or for whole body scan. Moreover, it looks for places where the gallium has collected in the body to see infection, inflammation or cancer.
– A renogram is performed using a special radioactive material , when injected into the blood stream shows the kidney blood supply and filtering action of the kidneys.
What are the common uses of Nuclear scans?
The common uses of Nuclear scans are:-
Nuclear scan for Heart:
- Visualize heart blood flow and function (such as a myocardial perfusion scan)
- Detect coronary artery disease and the extent of coronary stenosis
- Assess damage to the heart following a heart attack
- To evaluate treatment options such as bypass heart surgery and angioplasty
- For evaluating the results of revascularization (blood flow restoration) procedures
- To evaluate heart function before and after chemotherapy (MUGA)
Nuclear scan for Lungs:
- Scan lungs for respiratory and blood flow problems
- Assess differential lung function for lung reduction or transplant surgery
- Detect lung transplant rejection
Nuclear scan for Bones:
- To evaluate bones for fractures, infection and arthritis
- For evaluating for metastatic bone disease
- To evaluate painful prosthetic joints
- For evaluating bone tumors
- Identify sites for biopsy
Nuclear scan for Brain:
- Investigate abnormalities in the brain in patients with certain symptoms or disorders, such as seizures, memory loss and suspected abnormalities in blood flow
- Detect the early onset of neurological disorders such as Alzheimer’s disease
- Assist in surgical planning and identify the areas of the brain that may be causing seizures
- Evaluate for abnormalities in a chemical in the brain involved in controlling movement in patients with suspected Parkinson’s disease or related movement disorders
- Evaluation for suspected brain tumor recurrence, surgical or radiation planning or localization for biopsy
Nuclear scan for Other Systems:
- Identify inflammation or abnormal function of the gallbladder
- Identify bleeding into the bowel
- Assess post-operative complications of gallbladder surgery
- Evaluate lymphedema
- Evaluate fever of unknown origin
- Locate the presence of infection
- Measure thyroid function to detect an overactive or underactive thyroid
- Help diagnose hyperthyroidism and blood cell disorders
- Evaluate for hyperparathyroidism (overactive parathyroid gland)
- Evaluate spinal fluid flow and potential spinal fluid leaks
Nuclear scan for Cancer:
- For determining cancer stage or spread of cancer in various parts of the body
- To localize sentinel lymph nodes before surgery in patients with breast cancer or skin and soft tissue tumors
- For planning treatment
- To evaluate response to therapy
- For detecting the recurrence of cancer
- To detect rare tumors of the pancreas and adrenal glands
Nuclear scan for Renal:
- To analyze native and transplant kidney blood flow and function
- For detecting urinary tract obstruction
- To evaluate for hypertension (high blood pressure) related to the kidney arteries
- For evaluating kidneys for infection versus scar
- To detect and follow-up urinary reflux
Preparation for the nuclear test:
By and large, the steps to prepare for nuclear scan depend on the type of test and tissue that will be studied. Before test patient is required to undergo fasting for 2 to 12 hours
For others, you may be ask to take a laxative or use an enema. The medical team can ask a patient to avoid some medicines, drugs, vitamins, and herbs before the test. In fact, reactions to the radioactive material are very rare. Hence, known allergies must be conveyed to the medical team. The radioactive material can be incline anywhere from a few minutes to many hours.