White Blood Cell Scan

What is it?

A Nuclear Medicine WBC Scan is performed using a special radioactive material which is tagged to your white blood cells that, when injected into the body, is attached to sites of inflammation. Once distributed in these areas, the inflammation (infection) can be seen.

Nuclear Medicine scans are performed using very small amounts of radioactive material. The radioactive material is usually bound to other non-radioactive elements. These combined elements are called "radionuclide". The radionuclide emit energy called "photons". Radionuclide can be directed to many organs and systems in the body. Once a radionuclide is distributed in an organ or system, the photon energy is collected by a "Gamma Camera". The Gamma Camera detects the pattern of distribution of the radionuclide in the body and sends this information to a computer. The computer processes the information and displays the information in the form of a picture.

Nuclear Medicine exams differ from other x-ray procedures because the energy (x-rays and photons) come from different sources. X-ray energy is created by the x-ray tube and pass through the body. Another major difference is that Nuclear Medicine exams best demonstrate body physiology (system function), whereas x-rays show anatomical detail.

What will happen to me?

The Nuclear Medicine Technologist will draw some blood from a vein in your arm. Your blood will then be mixed with a special radionuclide (tagging process) that will stick to the white blood cells in your blood. Your blood mixed with the radionuclide will then be re-injected into your vein. The blood will distribute the radionuclide throughout your body. After the injection, it takes 24 hours before the radionuclide is adequately distributed and a picture can be taken. To start the scan, the technologist will position you on a flat table and will place you under the Gamma Camera. The Gamma Camera will be very close to you to obtain the best picture.

How long will this test take?

The blood tagging process is an all day exam, requiring you to return for several scans at the Nuclear Medicine Department. After the injection, you will need to return to the Nuclear Medicine Department four (4) hours later for the first picture. Once the actual scan is started it takes 60 - 90 minutes to complete depending on the area of your body being examined. White blood cells collect in infection areas very slowly. For this reason, it is necessary to repeat the scan portion of the exam again at five (5) hours and eight (8) hours after the initial injection so that several pictures can be studied. When you return to the Nuclear Medicine Department for delayed pictures it will take 60 - 90 minutes to complete the picture. However, the tagged white blood cell injection is only given on the initial visit.

What will I feel, will it hurt?

You may feel a slight pinprick in the vein of your arm when your blood is taken and when the tagged blood is re-injected. You will not feel any effects from the radionuclide injection. When your scan is begun, you will need to lay flat on a table. You will need to lay very still while the scan is being performed so that the best picture can be made. You will not feel any effects from the Gamma Camera. It does not create radiation, it only detects the radiation coming from the injected radionuclide. The Gamma Camera is a large machine that collects the emitted photons from the radionuclide but produces very little sound. The Gamma Camera must be very close to you and will be moved over your body to obtain the pictures. The radiation will totally disappear from your body in about 96 hours (4-5 days). The radiation exposure you receive for the WBC Scan is no more than from a routine x-ray procedure.

What will the test show?

The radionuclide is distributed throughout your body. If any areas of infection are present, the tagged white blood cells will collect in these area and be seen on the pictures.

How do I get ready?

You can eat as you normally do. Just before the start of your scan, you will need to urinate and empty your bladder so that you are as comfortable as possible during the exam. You should remove any metal such as belt buckle, earrings, necklaces, keys, etc., since these will interfere with the pictures.

Reviewed: May 2005