Scintigraphy
A scintigraphy is a nuclear medicine test that generates images of parts of the body. It is carried out in a hospital by the radiology department. A small amount of mildly radioactive tracer material is injected into a vein to produce images that will help the physician visualize the functioning of organs. The material concentrates in the part of the body to be studied. A device known as a gamma camera captures the signal emitted by the radioactive material and converts it into an image. The image is known as a scintiscan. Scintigraphy can be static (where the device is stationary) or dynamic (where the device scans over the part of the body being examined).
Many organs including the brain, thyroid gland, lungs, heart, liver, kidneys, spleen as well as bones can be observed through scintigraphy. The amount of radiation absorbed during this test is low and comparable to what is emitted during a chest X-ray. The injected radioactive material is rapidly flushed through the body by the kidneys.
What does an abnormal result mean?
A specialist will study the images. Although the results will provide the physician with certain elements, this test alone is seldom enough to make a clear diagnosis. It is by analysing the results of this test, along with other elements in the patient's medical file, that the physician will be able to draw any conclusions. Here are a few of the most commonly ordered scintigraphies.
Cardiac scintigraphy (myocardium) with stress test |
ObjectiveThe objective of this test is to provoke cardiac stress through physical exercise (walking or running on a treadmill). The imaging technique is used to watch the change in blood flow due to exercise. When the heart is working hard, its blood vessels fill with blood to supply it with additional oxygen. The test allows us to see how this blood is distributed throughout the heart muscle. The radioactive substance that is injected into the body enables us to monitor its flow. Pictures are taken before and after patients exert themselves on the treadmill. The physician then compares the results to provide information on the patient's condition. ContraindicationsAnyone with a heart problem unable to undertake this type of test. There is an alternative: cardiac scintigraphy with Persantinee®. DurationGenerally speaking, the test takes 20 to 30 minutes to complete. This includes preparing the patient for the test, injecting the material and the treadmill portion. Final images take about 20 to 25 minutes to generate. Side effectsBecause this test requires a great deal of physical effort, some people experience chest pain afterwards. Préparation
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Cardiac scintigraphy (myocardium) with Persantine® (Mibi Persantine®) |
ObjectiveThe objective of this test is to provoke cardiac stress by injecting the patient with Persantine®. The imaging technique is used to watch the change in blood flow caused by the drug. When the heart is working hard, its blood vessels fill with blood to supply it with additional oxygen. The test allows us to see how this blood is distributed throughout the heart muscle. The radioactive substance that is injected into the body enables us to monitor its flow. Persantine® tests are administered to those who are unable to run on a treadmill. Images are taken before and after the Persantine® injection. The physician then compares the results to provide information
on the patient's condition.
ContraindicationsThis test is associated with several contraindications:
ProcedureAn intravenous catheter is inserted into the patient's forearm. A radioactive tracer material is then injected and images are taken. Afterwards, Persantine® is administered to the patient and the radioactive material is injected once again. A second set of pictures is then taken. DurationIt takes between 20 and 60 minutes to prepare the patient and to give the injections. Then, they must wait for a few hours. Final images take about 20 to 25 minutes to generate. Side effectsPersantine® causes a great deal of stress on the heart. Some people experience chest pain afterwards. Headache, nausea, hot flushes and dizziness have been reported. Preparation
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Bone scintigraphy |
ObjectiveThe objective of this test is to assess the balance between the formation and destruction of bone (bone metabolism). It can highlight areas of inflammation on the bones as well as lesions that are not always painful or visible on other tests. Bone scintigraphy helps identify metastases, fractures and osteoarthritis. ContraindicationsSome centres consider taking Didronel® or Didrocal® in the 2 weeks leading up to the test as contraindicated. ProcedureBone scintigraphy is simple and painless but is quite lengthy. A radioactive agent is injected into a vein. Images may be taken as the radioactive agent is making its way to the bones. The patient must then wait a few hours. During this time, one can eat and drink. Drinking plenty of fluids during this time is highly recommended as it improves the distribution of the product and also helps flush it out after the test. Patients are asked to urinate right before the images are taken. DurationThis test takes 4 to 6 hours to complete. Side effectsNormally, no adverse effects are associated with this test. PreparationNo specific preparation is required before the examination. |
Thyroid scintigraphy |
ObjectiveThis test is used to assess the shape, size and position of the thyroid gland. ContraindicationsThyroid scintigraphy is associated with some contraindications. Patients who have undergone iodine-based radiological examinations in the 4 to 8 weeks leading up to this test should mention it before the procedure is initiated. The same applies to those who are taking or have taken Synthroid® in the 4 to 6 weeks leading up to the test, or Cytomel® in the last week or propylthiouracil in the last week. It is also important to mention whether you are taking medications or natural products that contain iodine such as Cordarone®, for example. ProcedureThe patient is injected with a radioactive agent and is then asked to wait 15 to 20 minutes. After the waiting period is over, images are taken. This examination is usually performed along with other tests. Other thyroid tests are generally ordered (thyroid uptake). DurationThis test generally takes 30 to 60 minutes to complete. Side effectsNormally, no adverse effects are associated with this test. PreparationNo specific preparation is required before the examination. It's better not to wear jewelry if going for this test. |
What to know before going for this test
Before going for a blood test, examination or other, it is always a good idea for you to have a complete list of all prescription or over the counter medications and/or natural products you may be taking. If you are unsure or have any questions, your pharmacist will be able provide you with additional information.
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.