A computerized tomography (CT) scan is a type of imaging test that can produce detailed images of structures inside the body. Doctors can use CT scans to diagnose kidney cancer.

A CT scan combines data from a consecutive series of X-rays to produce high resolution images. Alongside assisting with the diagnosis of kidney cancer, it can also help a doctor determine whether the cancer has spread to other parts of the body.

This article discusses the role of CT scans in kidney cancer. It also outlines how to prepare for a CT scan, what to expect during the procedure, and the possible risks.

A medical professional is looking at a computer.Share on Pinterest
Hispanolistic/Getty Images

Doctors can use CT scans for several purposes.

They can be effective in helping to diagnose kidney cancer. A CT scan can also help determine more about a tumor, such as its:

  • size
  • shape
  • location

If a person has kidney cancer, a doctor may also order a CT scan to:

  • understand the stage of the cancer
  • determine where to perform a biopsy procedure
  • check where to guide certain local treatments, such as:
  • help plan external-beam radiation therapy
  • check whether the cancer is responding to certain treatments
  • assess whether the cancer has recurred after treatment

Learn about kidney cancer.

If a doctor suspects a person may have kidney cancer, they may use a CT scan to help confirm their diagnosis.

Signs and symptoms of kidney cancer include:

Learn about the early symptoms of kidney cancer.

A doctor may advise a person to avoid eating for a certain time before their CT scan.

People should also inform their doctor if they:

  • have any allergies
  • have kidney problems
  • take any medication, particularly for diabetes

A person should also tell the hospital if they are pregnant — a doctor may reduce the radiation dose or use an alternative imaging method.

People may also wish to wear loose clothing — they may be able to stay in these during the scan, or it will make it easier to change into a gown if necessary.

Individuals should also avoid wearing jewelry and clothing containing metal, as they must remove any metal before the scan.

During a CT scan, a person will usually wear a hospital gown and lie on a motorized flat table that accurately positions the individual for scanning. This table then passes slowly through the center of the X-ray machine as it creates the images. With some scanners, the table will remain still, and the machine will move around the individual.

A medical professional may ask the person to hold their breath for parts of the procedure. This helps prevent the images from being blurry.

A CT scan can last from a few minutes to half an hour. It is noninvasive and does not cause any pain. However, in some cases, lying in one position during the procedure may cause slight discomfort.

CT scans may sometimes involve the use of a contrast agent or dye. This can help highlight specific areas inside the kidney to create clearer images.

A person may take the dye:

  • orally
  • intravenously
  • via an enema

CT scans most often occur on an outpatient basis at a hospital or a radiology center.

A person’s doctor can provide more information about what to expect during the procedure.

How CT scans work.

CT scans use X-rays, which are a form of ionizing radiation. Cumulative excess exposure to ionizing radiation can increase a person’s risk of developing cancer.

CT scans cause higher radiation exposure than standard X-rays, which use relatively low levels of radiation. However, the increased risk of developing cancer from a CT scan is still small.

In some very rare cases, the contrast agents or dyes that doctors use during a CT scan can cause kidney problems. This is more likely to happen in people with impaired kidney function. In this case, doctors may administer an alternate contrast agent or opt for a different imaging study.

A doctor may use several other tests to help diagnose kidney cancer. These include:

Learn more about the tests to screen for kidney cancer.

Here are some common questions about CT scans and kidney cancer.

Can you see kidney cancer on a CT scan?

A doctor can see kidney cancer tumors on a CT scan. They can also identify the location, size, and stage of the cancer using this imaging test.

How accurate is a CT scan for kidney cancer?

CT scans for kidney cancer are typically highly accurate. A 2020 research article stated that CT scans for kidney cancer had an accuracy rate higher than 99%.

What is the best test to detect kidney cancer?

A doctor may use various tests to detect kidney cancer. Imaging tests for kidney cancer include:

  • CT scans
  • ultrasound scans
  • MRI scans
  • angiographies

Medical professionals may also request blood tests, urine tests, and a biopsy.

Why else would a doctor order a CT scan of the kidney?

CT scans can be useful in diagnosing other conditions affecting the kidneys. A doctor may order a CT scan if they suspect the person has kidney stones.

A CT scan can also help diagnose renal abscesses. It can also help a doctor diagnose polycystic kidney disease.

Learn more about the kidneys and their related conditions.

A CT scan uses several X-rays to produce detailed images of structures inside the body. Doctors can use CT scans to diagnose kidney cancer, as it helps determine a tumor’s size, shape, and location.

A doctor may also use a CT scan to help perform a biopsy and where to guide local treatments, such as cryotherapy, radiofrequency ablation, and implantation of radioactive seeds.

CT scans can also help monitor treatments or check whether the cancer has returned.

A doctor can advise on preparing for the procedure and what to expect.