Imaging scans

Various imaging scans can create pictures of the inside of your body and provide different types of information.

You will usually have at least one of the following imaging scans:

• Ultrasound
• CT scan
• MRI scan
• Radioisotope bone scan
• PET scan

Ultrasound 

An ultrasound uses soundwaves to create pictures of your internal organs. These might show if there is a tumour in your kidney. During an ultrasound, you will lie on a bench and uncover your abdomen (belly) or back. A cool gel will be spread on your skin, and a small handheld device called a transducer will be moved across the area. The transducer creates soundwaves that echo when they meet something solid, such as an organ or tumour. A computer turns the soundwaves into a picture. An ultrasound scan is painless and usually takes 15–20 minutes.

CT scan 

A CT (computerised tomography) scan uses x-ray beams and a computer to create a detailed picture of the inside of the body.

If kidney cancer is suspected on an ultrasound, your doctor will usually recommend a CT scan. This will help find any tumours in the kidneys, and provide information about the size, shape and position of a tumour. The scan also helps check if a cancer has spread to nearby lymph nodes or to other organs and tissues.

CT scans are usually done at a hospital or radiology clinic. You may be asked to fast (not eat or drink) for several hours before the scan to make the pictures clearer and easier to read.

Before the scan, a dye may be injected into a vein in your arm. This dye, known as contrast, helps make the pictures clearer. It travels through your bloodstream to the kidneys, ureters, bladder and other organs. The dye might make you feel flushed and hot for a few minutes and you could feel like you need to pass urine. These effects won’t last long.

During the scan, you will need to lie still on a table that moves in and out of the scanner, which is large and round like a doughnut. This painless test takes about 30–40 minutes.

MRI scan 

An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to create detailed, cross-sectional pictures of the inside of your body. Most people with kidney cancer won’t need an MRI, but it might be used to check whether cancer has spread from the kidney to the renal vein or spinal cord.

Let your medical team know if you have a pacemaker or any other metallic object in your body. If you do, you may not be able to have an MRI scan, although some newer devices are safe to go into the scanner. Before the MRI, you may be injected with a dye to help make the pictures clearer. An MRI without dye may be used instead of a CT scan if you have pre-existing kidney problems and cannot have the dye.

During the scan, you will lie on an examination table that slides into a large metal tube that is open at both ends. Lying within the noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may become distressed, mention this beforehand to your medical team. You may be given a mild sedative to help you relax, and you will usually be offered headphones or earplugs.

The MRI scan takes between 30 and 90 minutes.

Radioisotope bone scan 

Also called a nuclear medicine bone scan or simply a bone scan, this scan can show if kidney cancer has spread to your bones. It’s used only if you have bone pain or if blood tests show high levels of alkaline phosphatase. (High levels of this enzyme could be a sign that kidney cancer has spread to the bones.) If cancer is found in the bones, the scan can also be used to check how the cancer is responding to treatment.

Before the scan, a tiny amount of a radioactive substance is injected into a vein. The substance collects in areas of abnormal bone growth. You will need to wait for a few hours while it moves through your bloodstream to your bones. Your body will be scanned with a machine that detects radiation. A larger amount of the substance will usually show up in any areas of bone with cancer cells.

Precautions to take

Radioisotope bone scans generally do not cause any side effects. After the scan, you need to drink plenty of fluids to help remove the radioactive substance from your body through your urine. You should avoid contact with young children and pregnant women for the rest of the day after your scan. Your treatment team will discuss these precautions with you.

PET scan

A PET (positron emission tomography) scan is a specialised imaging test. It uses an injection of a small amount of radioactive solution to help cancer cells show up brighter on the scan. A PET scan is useful for some cancers, but kidney cancer does not always show up well on a standard PET scan, so most people don’t need one.

→ READ MORE: Tissue biopsy

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