This page is about your gastro‑oesophageal reflux (MILK) scan at Royal Brompton Hospital. It tells you about the scan, what will happen at your appointment and what to expect on the day. 

A gastro‑oesophageal reflux scan, also known as a MILK scan, helps us see whether milk or liquid is coming back up from the stomach into the oesophagus (reflux). It can also show how quickly your child’s stomach empties.

We mix a very small amount of radioactive tracer with milk, breast milk, formula, or (for older children) a soft drink. The tracer is not absorbed by the stomach. It simply travels with the liquid so we can take pictures with a gamma camera as it moves through the stomach and intestines.

We understand that bringing a child for a scan can feel stressful. This page explains what will happen, how to prepare, and what to expect on the day. Our team will support you and your child throughout the visit.

What the scan involves

Preparing the drink

• When you arrive, a technologist will take the milk or drink you have brought with you.
• A small amount of tracer will be added to it.
• Your child will then be asked to drink the liquid. They can take up to 5 minutes if needed.

If your child is fed through a feeding tube (NG tube), we can use this for the scan. We will take a small sample of fluid from the tube to check the pH and confirm that the tube is correctly positioned in the stomach before starting.

The amount your child needs to drink depends on their age and feeding ability. This will be discussed with you on the day.

During the scan

• As soon as your child has finished the drink, we will start taking pictures.
• Your child will lie on the scanning couch for 1 hour while the camera takes continuous images.
• Your child will need to lie as still as possible. We encourage you to stay with them throughout to help keep them calm and comfortable.
• If stomach contents flow back up into the oesophagus (reflux), this will be visible on the images taken by the gamma camera.

After the first scan

• You may leave the department.
• We will usually ask you to return after 1 hour so we can take one final picture, which only takes a few minutes.

How to prepare

• Your child should have no food or drink from midnight (or no morning feed). We aim for them to be hungry enough to accept the drink for the scan.
• Do not give reflux medication that morning unless this has been agreed with the referrer.
• Bring up to 500 ml of milk, breast milk, formula, or (for older children) a soft drink of their choice. The exact amount needed will depend on your child’s age and feeding needs.
• The technologist will help your child get comfortable on the scanning couch.
• The scanner is similar in size to a CT scanner and quieter than an MRI scanner.
• If your child’s clothing has metal fastenings that cannot be removed, we may ask them to change into something more suitable.

Risks of radiation during a gastro‑oesophageal reflux (MILK) scan

The amount of radiation used during a paediatric lung scan is small and kept to a minimum. We believe that the benefits of having the scan far outweigh any risks.

The risk of a person getting cancer because of this radiation is very low, 1 in 100,000 to 1 in 10,000 people. This level of risk is very small compared with the overall lifetime chance of getting cancer. The overall lifetime chance of getting cancer is around 1 in 2 people. 

After the scan

• A doctor will check the images while you wait.
• Once the images are confirmed, you and your child can go home.
• The radiation dose from this scan is very small.
• There are no contact restrictions after this scan.
• Your child may eat and drink normally again straight away.
• The tracer will not make your child sleepy.

Your results

A nuclear medicine consultant will review your scan and send the report to your referring specialist. The results will also be available on the hospital’s electronic system.

Your specialist doctor will discuss the results with you and explain any next steps.