In the past, the most common way to look inside the human body was through exploratory surgery. But today doctors can use a huge array of non-invasive techniques. Some of these techniques include x-ray, MRI, CT scan, ultrasound and so on. Each of these techniques has advantages and disadvantages that make it useful for different conditions and different parts of the body. A nuclear medicine scan gives physicians another way to look inside the body. The purpose of this diagnostic study is to provide an image that evaluates organ function, and locates disease or tumors. Nuclear scans also show the size, shape and position of the organ being scanned. After you are given a low dose of a radioactive substance (may be referred to as a trace or radionuclide), images are able to be obtained with a special camera based on the energy produced by the radioactive substance. The extent to which the tracer is absorbed, or “taken up,” by a particular organ or tissue may indicate the level of function of that system. A diseased or poorly functioning organ will show a different signal than a healthy organ. One of the unique features of a nuclear medicine scan is that it shows the function of the organ or tissue being evaluated as opposed to just a picture. This helps to determine if the organ is working properly.
Nuclear medicine scans can be used to assist your healthcare provider in diagnosing disease, tumors, infection and other disorders by evaluating organ function.
Some of the specific reasons a nuclear medicine scan may be used include:
- Analyzing kidney function
- Image blood flow and function of the heart
- Scan lungs for respiratory and blood flow problems
- Identify blockage of the gallbladder
- Determine the presence or spread of cancer
- Measure thyroid function
- Evaluate bones for fracture, infection, arthritis or tumors
- Locate the presence of infection
Your healthcare provider will tell you if there are specific instructions on eating prior to your exam and whether or not you should take your routine medications. Wear loose, comfortable clothing for your test. Discuss with your healthcare provider if you are claustrophobic or worried about lying still during the scan. He or she may order medication to help you relax during the procedure. The radioactive material used is made precisely for the time of your test, so it is very important that you be on time.
Inform the technologist of all medications (over the counter and prescription) and herbs you are currently taking. There are medications that could possibly interfere with the radioactive materials given for your exam. Also, be sure to mention any recent imaging studies involving injected contrast media (dye) and oral or rectal contrast (such as in gastrointestinal studies) since they could also interfere.
Depending on the region being scanned, you may need to wear a hospital gown. Remove all jewelry, dentures and other media that may affect the scan by blocking the rays from the tracer.
Prior to the scan, you will be given a small amount of radioactive material, either by injection or orally. As this moves throughout the body, it can then be traced using a special camera called a gamma camera and a computer. It eventually collects in the organ being examined and gives off special rays called gamma rays. The amount of radiation that is “taken up” and then gives off gamma rays in a specific organ or tissue is linked to the functional activity of that organ or tissue. For example, cells which are dividing rapidly (like cancer cells) may be seen as “hot spots” of cell activity since they absorb more of the radioactive material. The gamma camera detects the rays and works with the computer to produce images and measurements of the organ and tissue.
It is possible that you will come in first for the administration of the tracer and then return later for the actual scan. Sometimes the entire procedure may be done during one visit. There are also exams that require multiple visits in a day or over a few days. The actual imaging time varies, but is generally less than an hour.
Prior to your exam, you may be asked to empty your bladder. As the tracer passes through the body, it eventually ends up in the bladder. If the bladder contains urine and tracer elements, it could possibly block the view of part of the pelvic bones if you are having a bone scan. When the exam starts, you will lie on a special exam table and be made as comfortable as possible. It is important for you to be able to lie still for the study. The technologist will be with you during the exam to assist in making you comfortable.
The gamma camera may be close to the area of your body that is being examined while the images are formed or it could be contained in a large doughnut-shaped structure similar to a CT scanner. If this is the case, you will be placed into the opening while lying on the table. Once the images are obtained and the computer processes the data, the physician with specialized training in nuclear medicine checks the quality of the images to ensure that an optimal study has been performed.
Once your nuclear medicine scan is complete, you may resume normal activity and eating habits. The radioactive material usually passes through the urine or stool within 48 to 72 hours.
Nuclear medicine scans have been used for decades and there are no know long-term adverse effects from such low-dose studies. It is important to know that the amount of radioactive material involved in a nuclear medicine scan is usually considerably lower than a patient would receive in a conventional x-ray study or CT scan. The radioactivity of the tracer is also very short-lived so exposure to radiation is limited.
The benefits of conducting a nuclear scan to diagnose a potentially serious condition usually outweigh concerns about radiation exposure.
Your test will be reviewed by a radiologist who specializes in nuclear medicine. Once he or she determines the results, a written report will be sent to your healthcare provider who will in turn give the results to you. New technology also allows for distribution of reports over the internet at our facility.