Your Differential Lung Function Scan explained

This patient information is for patients having a differential lung function scan. It aims to tell you what a Lung Function Test is and what will happen.

Differential Lung Function Scan ExplainedTo view a PDF you may need to download Adobe Reader.

General information

A doctor has asked us to take pictures of your lungs.

If the appointment clashes with another outpatient appointment, or you are unable to attend on this day, please contact this department as soon as possible.  We can then reschedule the test and assign the appointment to another patient.

As the test involves small amounts of radiation, we ask that you are not accompanied by children under 18 or anyone who may be pregnant. You may bring one adult with you to the department.

If you have mobility issues, are incontinent or claustrophobic please contact the department on the number provided.

Benefit and risks of the test

Everyone receives some radiation every day from the radioactivity in the air, food we eat and even from space.  The amount of radiation in a nuclear medicine test is similar to your natural exposure over one year so the risks associated with it are low.

The main benefit of the test is making the correct diagnosis, so you can get the treatment that is right for you.  This benefit is far greater than the small risk from radiation.

What does the test involve?

This test will take place on two separate days, however, depending on the information the doctor requires we may not be required to perform both parts of the test.

Part 1 (day 1)

In the first part, you will be asked to breathe in a radioactive mist (see photos).  This allows us to look at the air supply to your lungs.  After inhalation of the gas, you will lie or sit in a number of positions whilst we take pictures of the lungs with a Gamma Camera (see photos).  Once these pictures have been taken you are free to leave the department.

Part 2 (day 2)

The second part of the test takes place on a second day and involves giving a small injection of a radioactive tracer into one of the veins in your hands or arms.  It is very similar to having a blood sample taken and there should be no ill effects from the injection.  This allows us to look at the blood flow in the lungs.  Once the injection is given, you will lie or sit in a number of positions whilst we again take pictures of the lungs with the Gamma Camera. After the pictures have been taken, you will be free to leave.


If you are pregnant or breast-feeding you must inform the department as quickly as possible as special arrangements may have to be made.

There is no special preparation required for this test. Please eat and drink as normal.

Please bring a list of any medication that you are on with you to the department (your repeat prescription sheet if possible).

After the test

You must take extra care to wash your hands thoroughly after toilet use, sit down when you use the toilet and to flush the toilet twice.

When the test is completed, the images will be reviewed and a report will be available to the doctor who has requested the test.

The camera

The Gamma Camera used to take the pictures has an open design and the majority of patients complete the test without any discomfort.

Department of Nuclear Medicine

Lincoln County Hospital     01522 573103

Grantham Hospital              01476 464777