Nuclear Medicine
Nuclear medicine is a medical speciality that involves giving a patient a small amount of radioactive medication, called a radiopharmaceutical. This makes the body slightly radioactive for a short time. A special nuclear medicine camera detects the radiation as it is emitted (released) from the body, and takes images of how the inside of the body is working.
Many different organs can be imaged depending on the type of radioactive medication used. The radioactive medication is most commonly injected into the blood stream through a vein, but might be given in different ways, including:
- swallowed
- injected directly into the tissue beneath the skin
- injected into a shunt
- injected into a joint, or
- inhaled (breathed in)
Only a very small amount of radiopharmaceutical is given to keep the radiation dose to a minimum.
Nuclear medicine can also be used to treat some diseases or conditions. In these cases, the amount of radiopharmaceutical given is much greater, and it mostly goes to the diseased or abnormal organ. The type of radiopharmaceutical given usually emits ionising radiation that has the maximum effect on the part of the body or organ system being treated.
At San Radiology & Nuclear Medicine, we have the latest SPECT/CT machines producing exceptional image quality, lower radiation doses and faster scan times.
Nuclear Medicine imaging services
Bone Scan (Whole Body or Localised)
Before the test
There is no preparation for this test.
Please bring any previous scans and x-rays and your referral.
Please advise staff if you are or could be pregnant or are breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician and will be asked about your medical history.
You will then be given an injection of radioactive tracer by a qualified Nuclear Medicine Technologist into a vein in your arm. There are no side effects from this injection.
Immediate images may be taken at the time of the injection. You will then need to return 2-3 hours after the injection, so the tracer can accumulate in the bones. You may eat or drink during this time. We encourage you to drink a little extra fluid and empty your bladder as required.
When you return, you will be asked to empty your bladder. Then you will be placed on the scanning bed and a series of pictures will be taken. The length of the scan varies, however it normally takes 45-60 minutes.
Total time approximately: 4 hours
Once the images are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through urine and breaks down through natural decay over time.
Cardiac Amyloid
Before the test
There is no preparation for this test.
Please bring any previous scans and x-rays and your referral.
Please advise staff if you are or could be pregnant or are breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician and will be asked about your medical history.
You will then be given an injection of radioactive tracer by a qualified Nuclear Medicine Technologist into a vein in your arm. There are no side effects from this injection. There are no restrictions, you can eat and drink as normal.
You will then be asked to return 3 hours later for imaging. This allows the tracer to be taken up by the body.
Upon return, the Nuclear Medicine Technologist will position you on the scanner and take a series of images of your chest for approximately 30 minutes.
Once the pictures are completed, the doctor will complete a report. The images and report will be delivered to your referring doctor electronically.
Total time approximately: 3.5 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through urine and breaks down through natural decay over time.
Cardiac Myocardial Perfusion Study (MIBI)
Before the test
For this test there is important and special preparation. A nurse will call you a couple of days before your test to go over the preparation. Some of the preparation includes:
- No caffeine for 24 hours prior to the test.
- Certain medications may need to be stopped.
- Fasting for a couple of hours prior to the test.
What to expect
Myocardial Perfusion (MIBI) scans are performed to assess the blood flow to the heart. This test takes approximately 5 hours in total. The procedure has multiple parts:
- A cannula is placed into the vein of your arm that will be used multiple times during the examination
- The first part is an injection of a radioactive tracer. This injection has no side effects. After the injection there is a wait of up to 45 minutes for it to move around the body. Then the heart is scanned for approximately 15 minutes. These images are looking at the heart in rested state.
- A stress test is then performed with the doctor and a nurse. This is usually performed with a medication that is designed to dilate the vessels of the heart. You will then be given another radioactive injection after this medication has taken effect.
- After the stress test, you may be required to wait up to 45 minutes again before more scans of the heart are performed for a further 15 minutes. These images are looking at the heart in a stressed state.
Once the pictures are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
Total time approximately: 4-5 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through urine and gastro-intestinal system and breaks down naturally through decay
Hepatobiliary (HIDA)
Before the test
You will be required to fast for 4-6 hours.
Opioid medications are to be ceased for 24 hours before the test (Panadol and Nurofen only).
Please bring any previous scans and your referral.
Please advise staff if you are or could be pregnant or are breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician, and you will be asked about your medical history.
You will then be positioned on the scanning bed and given a radioactive injection into a vein in your arm. The radioactive injection circulates the body and goes to the liver and gallbladder. An image will be taken continuously for 1 hour – you are required to lay still for this. The image is looking to see your gallbladder fill.
If your gallbladder has filled – you will be given a drink of Ensure Plus and another 1 hour scan will be taken. This scan watches the gallbladder empty.
After both images are taken, the Nuclear Medicine Physician will need to process the images.
Once the pictures are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
Total time approximately: 2.5-3 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through natural decay over time.
Lung Scan (V/Q)
Before the test
There is no preparation for this test.
Please bring any previous scans and your referral.
Please advise staff if you are or could be pregnant or are breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician and will be asked about your medical history. This is a 2-part test to look at the airflow (ventilation) and blood flow (perfusion) to the lungs. This test takes approximately 30 minutes to perform. The two parts of this test include:
- The first part assessing the air flow to the lungs requires you to breath in a small amount of radioactive gas. The gas does not have any side effects, although a mild taste may be noted. Once a certain amount of this gas is in the lungs, scans are performed and takes 15 minutes.
- Immediately have the first part, an injection of a radioactive tracer is administered into the vein of your arm to allow for assessment of the blood flow within the lungs. Scans are performed after injection and take 15 minutes again.
Once the scan in complete, the Nuclear Medicine Physician will assess the images to determine if there is a risk of pulmonary embolism. You will be asked to wait in the department until the doctor reviews the images and lets you know the results.
Once the pictures are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
Total time approximately: 1 hour
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through urine and breaks down naturally through decay over time.
Lymphoscintigraphy (Breast)
Before the test
There is no preparation for this test.
Please bring any previous scans and your referral.
Please advise staff if you are or could be pregnant or breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician, and you will be asked about your medical history.
The Nuclear Medicine Physician will then give you up to four small radioactive injections around the area of interest. There are no side effect from these injections.
You will then be asked to massage the area for 10 minutes to stimulate lymphatic flow. A Nuclear Medicine Technologist will then take a series of pictures. This will take 20 minutes.
A second set of pictures will be taken about 2 hours after the injections. These will take about 45 minutes. If lymph nodes are visualised, it is during these pictures that the doctor will place some texta marks on your skin, which are to guide the surgeon in theatre.
Once the pictures are completed, the doctor will complete a report. The images and report will be given to you to take with you to surgery.
Total time approximately: 3-4 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through natural decay.
Lymphoscintigraphy (Melanoma)
Before the test
There is no preparation for this test.
Please bring any previous scans and your referral.
Please advise staff if you are or could be pregnant or breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician, and you will be asked about your medical history.
The Nuclear Medicine Physician will then give you up to four small radioactive injections around the area of interest. There are no side effect from these injections.
A Nuclear Medicine Technologist will then take a series of pictures. This will take 20 minutes.
A second set of pictures will be taken about 2 hours after the injections. These will take about 45 minutes. It is during these pictures that the doctor will place some texta marks on your skin, which are to guide the surgeon in theatre.
Once the pictures are completed, the doctor will complete a report. The images and report will be given to you to take with you to surgery.
Total time approximately: 3-4 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer you were injected with leaves your body through natural decay.
Renal DMSA
Before the test
There is no preparation for this test.
Please bring any previous scans and your referral.
Please advise staff if you are or could be pregnant or breast feeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician, and you will be asked about your medical history.
You will then be given an injection of a radioactive tracer into the vein of your arm. There are no side effects from this injection.
You will be given a return time 3 hours after your injection. You may eat and drink during this break.
When you return, you will be asked to empty your bladder and then placed on the scanning bed. The scan will take about 30 minutes.
Once the pictures are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
Total time approximately: 3.5 hours
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer leaves your body through urine and breaks down over time through natural decay.
Renal DTPA
Before the test
You need to drink 500 ml to 1 litre of water in the hour prior to your test. You can empty your bladder as required.
Please bring your previous scans and your referral.
Please advise staff if you are or could be pregnant or are breastfeeding.
What to expect
On arrival, you will be seen by our Nuclear Medicine Physician, and you will be asked about your medical history.
You will then be placed on our scanning bed where you will be given an injection of radioactive tracer in a vein of your arm through a cannula. There are no side effects from the injection. Images will be taken for 30 minutes watching the radioactive injection go into the kidneys. Sometimes it is necessary that a 2nd injection of a drug called Lasix is given. More images will be taken after this for 20 minutes. Lasix is given in some cases to make the kidneys work harder. This means the kidneys produce more urine and your bladder will fill quicker. Once the pictures are completed, the doctor will complete a report. The images and report will be delivered electronically to your referring doctor.
Total time approximately: 1 hour
How much radiation will I receive?
The amount of radiation you are exposed to in most Nuclear Medicine examinations is comparable to a routine CT scan. There are no precautions you need to take after the test. The radioactive tracer leaves your body through your urine and breaks down naturally through decay over time.
It is important to stay hydrated for a couple of hours after the test to flush out any remaining Lasix.
Frequently Asked Questions
What is a radiopharmaceutical?
A radiopharmaceutical is a medication used in nuclear medicine that has a radioactive part and a pharmaceutical part. The radioactive part is sometimes referred to as a radioactive label or a radioactive tracer. The radioactive part is an unstable element (radioisotope) that gives off energy as it decays (disintegrates or breaks down) and changes to a different element or energy state. The actual amount of the radioactive substance given for most imaging tests is usually very small; approximately millionths of a gram. The dose of ionising radiation received by a patient having a nuclear medicine test can be very low or moderate - the dose varies between different types of studies. The ionising radiation is in a similar range to that received from computed tomography (CT) imaging. The radioactive part is most commonly Technetium 99m, but other radioisotopes such as iodine 123, indium 111 and gallium 67 are also used. Fluorine 18 is a radioisotope used in positron emission tomography (PET) imaging.
The body does not feel the ionising radiation, and it does not make you 'warmer' or 'glow in the dark'. The number of times the nuclear medicine camera takes images does not determine the dose of ionising radiation received during a nuclear medicine test. It is determined by the type and amount of radiopharmaceutical injected, the half-life of the radioisotope and how quickly this is eliminated from the body in urine, stools or breath. The half-life is the time taken for half of the radioactive atoms to decay or change their energy state. For most radioisotopes used in nuclear medicine, this half-life is measured in hours, so after a day or so there is very little radioactivity remaining.
The pharmaceutical part can be a few atoms or a complex molecule that helps take the radioactive part to the area of the body being studied. It is mostly the choice of the pharmaceutical part that determines where the radiopharmaceutical will go in the body and what organ system will be shown. Technetium 99m MDP is used for a nuclear bone scan, whereas technetium 99m MAG3 is used for a nuclear renal scan.
What is a gamma camera?
A gamma camera is a machine that is able to detect and make images from the very small amounts of ionising radiation emitted from patients having a nuclear medicine study. The gamma camera usually has a table, often narrow, on which the patient lies. The images are taken using the camera 'head'.
A camera might have one, two or occasionally three heads, with one or more being used to obtain the images. Each camera head has a flat surface that has to be very close to the patient. The camera heads might be supported in a number of different ways using strong metal arms or a gantry. There are no unusual sensations associated with having images taken with a gamma camera and the machine makes no noise.
How is nuclear medicine different from normal x-ray and CT examinations?
During a normal x-ray or CT examination, an image is formed from the 'shadow' created by the body as it is positioned between the x-ray machine (source of the x-ray beam) and the x-ray detector. The body stops some, but not all, of the X-rays and the patient is not made radioactive by the X-rays.
In nuclear medicine studies, the radiopharmaceutical given to the patient makes them, and the organ system or body part being studied, radioactive for a short time. This ionising radiation (usually a gamma ray) is emitted or released from the body, and can be detected and measured using a nuclear medicine gamma camera. All living things contain some radioisotopes (such as carbon 14 and potassium 40); a nuclear medicine study will make them 'more radioactive than normal' for a short time – hours or days.
An x-ray or CT image is formed from ionising radiation (x-rays) that passes through the body, but does not arise from the body; whereas a nuclear medicine image is formed from the ionising radiation (usually gamma rays) emitted from within the body. A gamma ray has similar properties to an x-ray, but it arises from the nucleus of an atom, whereas an x-ray arises from the electron shell of an atom.
Another way that nuclear medicine is different from x-ray and CT examinations is that an x-ray study shows what something looks like. This gives indirect information about how it is working: normally, abnormally, diseased, injured and so on. In nuclear medicine studies, the radiopharmaceutical usually only goes to the part of the body or organ system if it has some function and so shows how it is working. The images can also give information about what the body part or organ system looks like.
Nuclear medicine and x-ray tests are often complementary, providing different information that together make a diagnosis more certain.
What are the benefits of a Nuclear Medicine Study?
A nuclear medicine study helps your doctor evaluate how a particular area of your body or organ system is working. It can give information about how an injury, disease or infection might be affecting your body. It can also be used to show improvement or deterioration of a known abnormality after any treatment you might have had. Nuclear medicine studies are very good at showing how an organ system is working, and often complement other investigations and imaging studies.
Reference: Inside Radiology, Royal Australian College and New Zealand College of Radiology (RANZCR, 2014) www.insideradiology.com.au