How Accurate Is a CT Scan for Cancer?

If your doctor has ordered a CT scan to check for possible cancer, it is of course unnerving. You likely have questions about this procedure. Here, we address the most common queries patients have before they have a CT test for cancer or other health concerns.

What Is a CT Scan?

Computed tomography, sometimes called a CAT scan, is a highly sophisticated type of x-ray imaging. Standard x-ray uses a broad beam of radiation to take an image from a single angle. CT uses a pinpoint beam to take multiple images from different angles, which are sent to a computer, which creates thin, cross-sectional pictures, called slices, of the area being investigated. The 3D computer composite can be rotated and viewed from various angles, enabling deeper discovery. Oftentimes, contrast material, given via injection or orally, is used to illuminate details.

What Does a CT Scan Show?

CT highlights internal organs, soft tissues and bones. It is used to study a tumor’s location, shape and size, and determine which blood vessels are feeding it. When a biopsy is needed, CT-guided biopsy can be used to collect tissue for examination, as well as perform minimally-invasive tumor treatment, such as radiofrequency ablation, which can destroy a tumor without surgery.

Going forward, CT can be used to monitor the progress of treatment.

Does a CT Scan Mean Something Serious?

Not necessarily. But if your doctor believes you may have a tumor, blood clot, serious infection or other issue, finding quick, accurate answers may be crucial to halting disease progression or preventing a potentially serious outcome. While no one wants to find cancer, letting it go undiagnosed gives it time to grow and spread, making it harder to treat successfully. The earliest possible discovery enables the best possible treatment.

What Cancers Show Up on CT Scan?

CT can discover many types of cancer in myriad organs and areas of the body, including:

  • Colorectal cancer

  • Ovarian cancer

  • Kidney cancer

  • Stomach cancer

  • Bladder cancer

  • Pancreatic cancer

  • Cancer of the ureter

  • Melanoma

  • Lymphoma

  • Hepatocellular carcinoma

  • Pheochromocytoma

CT can also isolate diseases of the gallbladder, liver and pancreas, such as:

  • Pancreatitis

  • Alcohol-related liver disease

  • Acute cholecystitis

  • Cholelithiasis

  • Blocked bile ducts

  • Kidney stones

  • Kidney infection

  • Polycystic kidney disease

Does a CT Scan Show Everything?

While CT provides much more detail of damage and disease of internal organs, bones and blood vessels than some other imaging technologies, it can’t show everything.

Some types of cancer, for example, prostate cancer, uterine cancer and some liver cancers, may be harder to image using computed tomography.

Why Would My Doctor Order a CT Scan Instead of an MRI?

CT scans are faster and easier for patients and more commonly used than MRI, which can be time-consuming and costly. MRI’s enclosed environment causes some patients to experience claustrophobia. 

People with metal in their bodies, such as pacemakers, artificial heart valves, plates, pins, IUD, artificial joints, eye implants and other devices may not be able to have an MRI due to the powerful magnet it employs to create images.

How Is a CT Scan Performed?

The scan is performed by a highly-trained technologist, who will help to position your body and take the images. If you have an implanted device like a pacemaker, let your technologist know beforehand so that it is not disturbed during the procedure.

You will be asked to lie still on a specialized table that slides into the center of a big doughnut-shaped scanner, which may click, whir or buzz as it captures a series of images. You may be repositioned and asked to hold your breath for brief periods to ensure the best quality pictures. The scan can take anywhere from a few minutes to half an hour, depending on the area being imaged, and is completely painless.

You’re free to leave once your appointment is done.

Are There Disadvantages of a CT Scan?

While CT itself is quick and painless, it often requires an injection or the ingestion of a contrast agent, which causes reactions in a small number of people, though they are typically minor and resolve quickly on their own.

CT does expose patients to ionizing radiation, which may marginally increase their lifetime cancer risk. But your physician considers this very small risk to be outweighed by the importance of discovering cancer or another potentially serious problem.

Women who are pregnant or breastfeeding should avoid CT.

Low-dose CT for Lung Cancer Screening

Another valuable use for CT is annual lung cancer screening for high-risk patients. Unlike regular CT, low-dose computed tomography, or LDCT, utilizes only a tiny dose of radiation to create images of the lungs to capture very early signs of cancer, so it is considered safe for yearly screening.

LDCT screening is recommended for current and former long-term heavy smokers age 50 and older. Although lung cancer is the leading cause of cancer death in the US, when caught early, it is highly treatable and survivable.

Talk to your clinician about whether LDCT might be right for you.

Radiology Associates for CT Scans

If your doctor has ordered a CT scan for you, you have a choice of providers for your service. Why choose Radiology Associates?

For more than 60 years, Radiology Associates has provided eastern Central Florida with the most advanced technologies and a dedicated team of Board-certified, fellowship-trained radiologists dedicated to unparalleled diagnostic and interventional care.

Radiology Associates is accredited in CT imaging by the American College of Radiology (ACR) for accuracy, safety and best practice standards.

For more information on CT imaging and other leading-edge services, call our care team at (386) 274-6000.