About Your Nuclear Medicine Scan

Answers To Some Common Questions About Nuclear Medicine Scans

What Is Nuclear Medicine Imaging?

Nuclear Medicine is a method of obtaining diagnostic images by giving the patient a small dose of a radioactive isotope. Pictures are then taken with a special camera which is able to detect the location of the radiopharmaceutical in the body and create images which the physician can evaluate.

How Is The Dose Given And Is It Harmful?

The radioisotope dose is given either by an IV injection in the arm, breathing an aerosol, or swallowing a capsule.
The radioactive isotope is combined with a "tag" substance which will make it collect in the organ or system the doctor wants to evaluate. How the dose is given is determined by the area of the body that is being studied.

The radiation dose to the body is comparable to an X-ray exam and there are no side effects with the materials used.

What Happens After The Dose Is Given?

A camera will be used to take pictures. The camera may be installed in a hospital or physician's clinic, or it may also be housed in a mobile imaging vehicle. In both instances, the camera works the same way and gives the same results.

Some exams require a delay after the dose is given and before the pictures are started. This delay is required to give the dose time to collect in the organ being studied. Bone scans, heart scans, and thyroid scans often have delays. Other exams, such as renal scans, start immediately after the dose is administered.

The patient may be asked to lie down or sit in front of the camera. The technologist will position the camera close to the area of the body that is to be imaged.

Scans range in time from a few minutes to several hours depending on the type of exam being done. The camera does not have any effect on the body and the technologist makes the patient as comfortable as possible before starting the exam.

What Does The Test Show?

Nuclear medicine studies are different from most X-ray, Ultrasound, or CT examinations because they specialize in showing some aspect of the function of the body system being studied. Very simply, nuclear medicine studies look at how a specific organ is working (e.g. blood supply to the organ). Physicians often order an X-ray and a nuclear study to determine both structure and function.

What Must Be Done To Prepare For The Test?

For many of the exams there are no special instructions to follow before the test; however, gallbladder or cardiac exams may require that the patient not eat for four hours prior to the test. Some tests may also require that certain medications be stopped. The patient should be instructed by his/her physician or the scheduling personnel at the facility prior to the test.

Ample time should be arranged on the day of the test to allow time for additional views or delayed images which may be required. Time requirements for the test, which are relayed by scheduling personnel, are only estimates. Actual time requirements vary from patient to patient.

Combined Nuclear Medicine Patient Guide

A Bone Scan is an exam of the skeleton and may be of a limited area or the whole skeleton and takes approximately 4 hours. After your injection you are free to leave for 2 ½ to 3 hours and will be asked to drink 3 to 4 glasses of fluid. Upon your return the images will take 15 to 60 minutes, depending on your doctor's orders.

A Hepatobiliary Scan is an exam of the gallbladder that takes approximately 2 hours and requires that you have nothing to eat or drink 4 to 6 hours before the test.

A Lung Scan is a two-part exam of the lungs including air flow and blood flow to the lungs and takes approximately 1 hour. This exam requires that you have a chest x-ray before or after the scan.

A Myocardial Perfusion Scan is a stress test of your heart that takes approximately 4 hours and requires that you have nothing to eat or drink for 4 hours before the test. You must also avoid food or drink containing caffeine or chocolate including decaffeinated or caffeine-free products for 24 hours before the test. Wear comfortable shoes for the exercise portion of the test. If you are unable to walk on a treadmill, your doctor may schedule a pharmacological stress test using medication rather than exercise.

A Renal Scan is an exam of the kidneys that takes approximately 1 hour and requires that you drink 3 to 4 glasses of water before you arrive for your study. If you are having a Captopril MAG 3 renal scan, please inform the person scheduling the exam of all the medications you are taking.

A Thyroid Scan is an exam of the thyroid gland that can be performed 2 different ways. A 99m Technetium Scan requires an IV injection and requires approximately 45 minutes. For an I-123 Iodine Scan you will be given an oral capsule to take; you may leave for 4 to 6 hours and the scan requires 5 minutes upon your return. A 24-hour set of images may be required taking about 15 minutes. Your doctor will instruct you on what medications you may be taking that must be discontinued for the exam.