Study Shows CT Scans Cause Cancer

by Leah Masel

While prescribed freely across the United States, CT scans expose patients to significant amounts of radiation, a risk many people never fully learn about.

Over 93 million (Computed Tomography ) CT scans are performed yearly in the United States, which is a 30-fold increase compared to the 3 million a year performed back in the 90s and early 2000s.

While touted as safe, CT scans pose some serious health risks and are chronically overused and overprescribed in the United States at particularly alarming rates. CT scans expose patients to high doses of ionizing radiation (up to 500–1000 times more than a standard X-ray), which increases long-term cancer risk significantly.

CT scans emit a lot of radiation, specifically ionizing radiation, which has been shown to cause damage to DNA, leading to cell mutations, which could lead to tumors, cancers, etc. 

In fact, a single CT scan is the equivalent of 100 X-rays to your chest.

Radiation aside, the contrast dyes being used during the CT scan have been shown to have negative side effects as well. The dye used during the procedure must be filtered out by the kidneys. This dye has been linked to kidney failure and acute kidney injury (AKI). Those with preexisting kidney conditions or diabetes are at higher risk.

Also, people have been shown to have allergic reactions to the dye as well, ranging from mild reactions like hives to anaphylaxis.

In a peer-reviewed study by JAMA Internal Medicine back in 2025, which examined projected cancer rates as a result of the increase in CT scans, researchers predicted that if this overuse of CT scans continues, there will be 103,000 future radiation-related cancers.

Aditionally, Studies show that CT scans are also not accurate, and their results can shift and change. In 2011, a team of researchers at Memorial Sloan Kettering Cancer Center took 30 cancer patients, all with stage III and IV cancers, and did two separate CT scans within 15 minutes. All the patients had a tumor at least 1 centimeter in size.

Their findings were that the size of the tumor, according to the scan, changed drastically within those 15 minutes, with size fluctuations ranging between a 23% decrease in size and a 30 percent increase. This shows that results are many times inaccurate and can change due to angles of when the scan was taken, etc.

Overall, CT scans do come with significant health risks and should be used and prescribed sparingly.