Doctors do not usually use CT scans to diagnose prostate cancer, but they sometimes use them to see whether cancer has spread to other tissues.

The survival rate of prostate cancer tends to be very high when the cancer is detected before it spreads to distant body parts. People with cancer isolated to the prostate have about a 99% chance of living 5 years, compared with a person who does not have prostate cancer.

Doctors use a variety of tests to diagnose and monitor prostate cancer. A computed tomography (CT) scan is sometimes used to see whether the cancer has spread to other structures in your pelvis.

But CT scans aren’t usually used to actually diagnose prostate cancer. This is because other types of imaging, such as MRI scans can create a better picture of the different tissues in your prostate.

Read on to learn more about how doctors use CT scans for managing prostate cancer.

CT scans are a series of X-rays that create a 3D image of the inside of your body. They’re commonly used to:

  • diagnose conditions
  • guide tests and treatments
  • monitor how a condition is changing

Doctors do not typically use CT scans to diagnose prostate cancer because the prostate generally doesn’t show up well on the images created by the scan. More commonly, doctors use them to determine whether prostate cancer has spread to lymph nodes or other structures in your pelvis.

Doctors also sometimes combine a CT scan with another type of imaging, called a PET scan. During a PET scan, a substance that gives off a small amount of radiation is injected into your body, so that doctors can see how a certain part of your body is working. The combination of these two types of scans is called a PET-CT scan.

One type of CT scan uses a radioactive substance that targets a specific protein, called prostate-specific membrane antigen (PSMA), produced by the prostate. This type of scan is called a PSMA PET-CT scan.

It’s a very accurate type of imaging that can potentially show doctors whether your prostate cancer has spread to distant parts of your body. Cancer that has spread to distant tissues is called metastatic prostate cancer.

In a 2020 study, researchers in Australia found that PSMA PET-CT scans were more accurate at diagnosing metastatic prostate cancer than the standard technique of CT scans and bone scans.

Doctors use a variety of imaging tests to diagnose and monitor prostate cancer, such as:

Imaging techniquePurpose
CT scan•to help determine whether the cancer has spread to lymph nodes
•to see if the cancer has grown into other structures in your pelvis after treatment
transrectal ultrasound•to examine your prostate after irregular digital rectal exam or PSA test results
•to guide prostate biopsy or treatments like brachytherapy
•to measure the size of your prostate
MRI scan•to determine whether you should get a biopsy
•to guide a biopsy
•to determine the extent of cancer and to see whether it has spread
bone scan•to see whether the cancer has spread to bone
PET scan•to determine where prostate cancer has spread when it’s not clear
•to determine whether the cancer can be treated with radiopharmaceuticals

Currently, the most precise imaging technique for suspected prostate cancer is a multiparametric MRI scan, according to research from 2021.

A multiparametric MRI scan produces a more detailed image of the prostate than a standard MRI scan. It involves combining multiple MRI techniques into a single scan.

A CT scan generally is not performed to diagnose prostate cancer. MRI gives better resolution and can better reveal irregularities in the prostate. CT scans are currently considered insufficient to diagnose and monitor prostate cancer, according to a 2021 study.

The growing use of artificial intelligence for analyzing imaging results may make CT scans a viable option for visualizing prostate cancer in the future.

In the 2021 study, researchers found some evidence that artificial intelligence-assisted CT scans might be able to accurately diagnose prostate cancer. Yet more research is needed.

CT scans have some advantages over MRI scans. They tend to be significantly faster, more widely available, and cheaper since the technology is less expensive. In a 2019 study, researchers found that only 11.1% of insurance providers cover prostate MRI scans for people who haven’t had a negative biopsy.

Most CT scans are completed within an hour, and the scan itself usually takes only about 10–20 minutes.

A PSMA PET-CT scan can take longer. Usually, you need to wait about an hour after the injection of the radioactive tracer to receive the scan.

A regular PET scan can take 30–60 minutes.

Doctors generally do not use a CT scan to examine prostate enlargement, but it might show up as an incidental finding.

A transrectal ultrasound is the most widely available and cost-effective method for estimating prostate volume, a 2020 study reports.

CT scans aren’t generally used to diagnose prostate cancer, but doctors sometimes use them to look for signs the cancer has spread to other structures in your pelvis. CT scans are also combined with PET scans to look for signs the cancer has spread to distant body parts.

The most accurate imaging test to diagnose prostate cancer is an MRI. scan Doctors use MRI scans to determine whether you need to get a biopsy and to guide biopsies.