Explanation

Bone scan are a special type of x ray. They are used to to look at how your bones are working, instead of what they look like, and to look for any problems or changes. Doctors can look at one particular joint or bone using a bone scan, or they can look at your whole body. Bone scans can be used to help diagnose cancer, or other conditions like arthritis or Perthes' disease.

The doctor injects a harmless dye into your blood and the x ray can see where the blood is going in your body. This is because the dye makes the blood glow on the x ray - like glow-in-the-dark stuff. There is usually more of the dye in areas where there is a lot going on in your bone, like if your bone is breaking down or repairing itself.

Why do I need it?

The scan shows doctors which parts of your bones are not working as well as they should be. It can also show if some bits are working too hard or growing abnormally.

Using a bone scan, doctors can see if there are any "hot spots", like fractures, infections or bone tumours , or "cold spots", like areas of low growth or density.

A bone scan can identify problems days or even months before they are seen with an x-ray.

How does it work?

Your body is made up of millions of little cells all doing different types of jobs, depending on their function.

Your bones have two main types of cells called osteoblasts and osteoclasts. They keep your bones healthy and new, and prevent overgrowth.

During a bone scan, you get medicines tagged with radiation called radioisotopes, which travel and attach themselves to your bones.

A machine called a gamma camera picks up the low dose of radiation that the radioisotopes give out, and takes a slow photo of all the bones in your body.

The parts of your bones that are growing too fast will have lots and lots of osteoblasts with lots and lots of radioisotopes, which will show up on the photo as a big "hot spot". A fracture, a tumour or an infection can show up as a hot spot on a bone scan. It's a bit like throwing a load of sweets into a playground - wherever the sweets land becomes crowded with kids - a "hot spot".

Some other rare conditions can stop the osteoblasts and osteoclasts working properly, producing "cold spots".

What does it show?

A bone scan will show fractures, bone tumours, Infections and even arthritis.

What happens?

On the day of the bone scan, a doctor will give you a small injection to get the radioisotopes into your bloodstream.

It may take the radioisotopes a few hours to get to your bones. Some will not find their way to your bones at all, and the doctor might ask you to get rid of these by going for a wee before the scan.

You then lie on a table where the gamma camera will take some pictures of the radiation that is sent out by the radioisotopes. The gamma camera is a big flat camera that will come very close to you, but will not touch you.

It is a camera that works very very slowly, so a bone scan can take up to, or even over, an hour, although you might get some breaks to stretch your legs during this time. The most important thing that you need to do is lie very still, otherwise the photo will become very blurred - just like what happens when you move in a normal photo.

It can be very hard to lie still for so long and your mum or dad will be allowed into the room with you to keep you company.

Will it hurt?

The injection can sting a tiny bit, but if you're worried about this you can have some special cream put on your skin that will make it go numb.

You don't feel anything at all when the camera is taking the pictures. The radiation coming from the radioisotopes is a very low dose and has a low risk of harm. You have received more radiation from the sun for most of your life than you will get during a bone scan.

What happens next?

A radiologist will look at the pictures and let your doctor know what they have found, so that you can get the right treatment. You will be able to go home after the bone scan. Depending on what the doctors find, you may need to get some x-rays of your bones to see if they will change over the next few months.