US researchers warn that while CT scans are vital for diagnosis, their X-ray radiation poses cancer risks. Unlike MRIs, which use magnets and radio waves, CTs use X-rays to create detailed body images. Experts urge caution to avoid unnecessary scans.
Why X-rays harm
The electromagnetic spectrum is divided based on wavelength, with visible light—what humans can see—sitting in the middle. This includes colors from red to violet. On one end of the spectrum are low-frequency, long-wavelength waves like radio, microwave, and infrared radiation, which carry less energy than visible light. MRI technology, for example, uses radio waves.
On the opposite end are high-frequency, short-wavelength waves, including ultraviolet (UV), X-rays, and gamma rays. These are more energetic and are known as "ionizing" radiation, which can remove electrons from atoms and potentially harm human tissue at a molecular level. This type of radiation can lead to health problems such as cancer—UV rays from sunlight being a common example.
Despite their risks, high-energy waves like X-rays are crucial in medicine, offering doctors important diagnostic information.
CT scans may account for 1 in 20 future cancer cases
A new study analyzed cancer risks in 61.5 million U.S. patients who had undergone CT scans. The findings suggest that CT-related radiation exposure could lead to around 103,000 cancer cases over the patients’ lifetimes—about 5% of the country's annual new cancer diagnoses if current scan rates continue.
CT scan use has increased by roughly 30% since 2007, with older adults, especially those aged 60–69, undergoing the most scans.
The study also revealed that abdominal and pelvic CTs pose the highest cancer risk for adults, while head scans present the greatest risk for children.
Notably, children scanned before their first birthday face a tenfold higher cancer risk compared to other age groups.
CT scans have some risk, but benefits are valuable
The data obtained in the study applies to US patients and the American medical system.
Smith-Bindman pointed to the misuse of CT as a diagnostic tool, including unnecessary or excessive scanning, including those used for respiratory infections or headaches.
She also highlighted variations in radiation doses used to effectively perform the scan, saying some patients receive excessive amounts that are not clinically needed.
Other professionals in the field agree that misuse of CT scans can pose risks to patients.
"It is a well-established fact that high-energy radiation causes cancer," said Pradip Deb, a radiation safety expert at RMIT University, Australia, who wasn't involved in the study.
Deb said while it's commonly understood that ionizing radiation like X-rays can damage DNA, and that increased exposure could exacerbate the severity of that damage, it's not clear how this would work for individuals.
"Not everyone who is exposed to radiation will get cancer," Deb said.
"The estimated risk [of exposure] sometimes can cause panic among the patients who are benefiting from radiation," Deb said. "Radiations are routinely used for diagnosis and treatment of cancer. This study has clearly established the importance of limiting the radiation dose where possible and of avoiding unnecessary CT scans if other low-radiation or no-radiation procedures can do the same job."
Source: DW
Bd-pratidin English/ Afia
