THE MEDICAL IMAGING EXPERIENCE
INFORMATION FOR THE PATIENT
NUCLEAR MEDICINE LUNG (V/Q) SCAN

WHAT IS IT?
A Nuclear Medicine Lung scan is performed to evaluate the adequacy of air to the lungs and the blood supply that carries oxygen rich blood from the lungs to the rest of the body.

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 "radionuclides". The radionuclides emit energy called "photons". Radionuclides 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. The photon energy is emitted from the radionuclide injection and passes out of 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?
There are two phases to the lung scan. In the first phase (ventilation phase) the Nuclear Medicine Technologist will assist you to sit or lay in front of the gamma camera. A special oxygen mouth piece will be placed in your mouth. You will be given breathing instruction as a supply of slightly radioactive oxygen mixture is administered through the mask. In the second phase, (perfusion phase) the technologist will inject a special radionuclide into your vein, usually in your arm. The blood will carry the radionuclide to your lungs. After the injection the technologist will position you in front of the gamma camera. The gamma camera will be very close to you to obtain the best picture. Pictures from different angles and positions will be completed so that all sides of your lungs can be seen.

HOW LONG WILL THIS TEST TAKE?
It takes 10 - 15 minutes to prepare for the scan after you arrive. The first phase of the lung scan (breathing through an oxygen mask) takes about 15 minutes to complete. The injection of the radionuclide to start the second phase takes only a few minutes. After the injection, the scan takes about 35 minutes to complete. The entire lung scan process will take about one hour.

WHAT WILL I FEEL -- WILL IT HURT?
You will not be able to taste or smell the radioactive oxygen mixture that you breath. You will not feel any effects from the gas. You may feel a slight pinprick in the vein of your arm when the radionuclide is injected. You will not feel any effects from the radionuclide injection. When the scan is started, you will need to hold 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 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 to obtain the pictures. The radiation will totally disappear from your body in about 48 hours. The radiation exposure you receive is no more than from a routine x-ray procedure.

WHAT WILL THE TEST SHOW?
The radionuclide is distributed in the lungs in different patterns depending on the blood flow and ventilation flow. If one area in the lungs receives more or less of the radionuclide than other areas this can be seen on the scan. The patterns of distribution give indications of lung problems such as blood clots and other pulmonary diseases.

HOW DO I GET READY?
You can eat as you normally do. Just before the start of your scan, you should urinate and empty your bladder so that you are as comfortable as possible during the exam. You will need to wear a hospital gown to prevent interference from buttons, pins, snaps, etc. since these may show up in the pictures.

Reviewed: August 1994