An MRI (magnetic resonance imaging) scan is similar to a CT scan but uses magnetism instead of x-rays to build up a detailed picture of areas of your body.

During the test you will be asked to lie very still on a couch inside a long tube for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It is also noisy, but you will be given earplugs or headphones.

Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort.

An MRI scan can often distinguish between different types of body tissue more precisely than a CT scan, so in some situations it will give extra information.

In this test, the doctor examines the area at the centre of your chest (mediastinum), and the lymph nodes closest to the lungs. These are often the first places that lung cancer spreads to, and so are usually checked for signs of cancer, especially if the plan is for you to have an operation to remove the cancer. The test is done under a general anaesthetic and will mean a short stay in hospital.

A small cut is made in the skin at the base of your neck, and a tube is passed into the chest. The tube has a light and camera at the end, and can magnify the areas it looks at. The doctor can see any abnormal areas, and may also take samples of the cells and lymph nodes to examine under a microscope.

A similar test, known as a thoracoscopy, involves making a small cut in the skin and inserting a similar tube into another part of your chest, to look directly at the cancer and take samples from it.

This test is usually done in the x-ray department, most commonly during a CT scan. A local anaesthetic is used to numb the area. You will then be asked to hold your breath while a thin needle is passed through the skin and into the lung. An x-ray is used to make sure that the needle is in the right place. The doctors will then take a sample of cells to be examined under a microscope. The biopsy is sometimes slightly uncomfortable, but it only takes a few minutes.

After a lung biopsy, a small number of people may develop air between the layers that cover the lungs. This is known as a pneumothorax. Symptoms of a pneumothorax include sharp chest pain, breathlessness and a tight chest. You may be asked to wait for a few hours after your biopsy, to make sure that you have not got a pneumothorax. Let your doctor or nurse know if you develop any symptoms.

A PET (positron emission tomography) scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of this mildly radioactive substance is injected into a vein, usually in your arm. A scan is then taken a couple of hours later. Areas of cancer usually take up more sugar than surrounding tissue and so show up on the scan.

PET scans can be used to find whether a lung cancer has spread beyond the lungs. They can also be used to examine any lumps that remain after treatment to see whether they are scar tissue or whether cancer cells are still present. PET scans are a new type of scan and you may have to travel to a specialist centre to have one. They are not always necessary but you can discuss with your doctor whether one would be useful in your case.

Ultrasound uses sound waves to look at the liver and the other organs in the upper part of the abdomen. It is the same sort of scan that is used on pregnant women.

Once you are lying comfortably on your back, a gel is spread on to the area to be scanned. A small device that produces sound waves is passed over the area and the sound waves are converted into a picture by computer. The test only takes a few minutes.

This is more sensitive than an x-ray, and shows up any abnormal areas of bone more clearly. However, it is not always clear whether an abnormality is caused by cancer or other conditions such as arthritis.

A small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Abnormal bone absorbs more radioactivity than normal bone, so these areas are highlighted and picked up by the scanner as 'hot spots'. There is generally a wait of 2–3 hours between having the injection and the scan taking place, so you may like to take a magazine or book to pass the time. The level of radioactivity used in the scan is very small and does not cause any harm.

If your doctor wants to remove your lung cancer using surgery, or is planning for you to have a course of radiotherapy, they may first ask you to have breathing tests to see how well your lungs are working.

It will probably take several days for the results of your tests to be ready, and this waiting period will obviously be an anxious time for you. It may help to talk things over with a close friend or relative. You may want to ring our cancer support service to ask any questions you have.