A UCSF Study Shows CT Radiation Is Highly Carcinogenic

Whether CT radiation causes cancer has long been a contentious topic. Recently, a new study conducted by the University of California, San Francisco (UCSF) and published in the prestigious journal JAMA Internal Medicine shows that cancers caused by CT scans may account for 5 percent of new cancer cases each year. In 2023, 93 million CT scans were performed in the United States, projected to cause nearly 103,000 new cancers—far higher than previous estimates. This finding has once again pushed the issue of CT-induced cancer to the forefront of public debate.

From ancient times to the present, iatrogenic diseases have objectively existed. Taking medications can likewise cause liver and kidney damage, cancer, teratogenicity, and various other iatrogenic harms, so CT-induced cancer is not surprising. It is just that the cancer rate in this study is 3 to 4 times higher than previous estimates, and this figure is startling.

CT is becoming increasingly common. Modern hospitals rely on CT scanning for various diagnoses, and health-screening institutions are also using CT extensively to screen the general population for cancer. CT scanning is both the key diagnostic tool for confirming cancer and the most commonly used tool for evaluating treatment response in cancer patients. CT causing cancer and CT accelerating cancer progression are both objective facts, but perhaps few people previously realized how startling this reality is. Oncologists are deeply worried and are warning people to minimize the frequency of CT scans.

CT can harm both adults and children. Studies show that the most common CT-radiation-related cancers in adults are lung cancer, colon cancer, leukemia, bladder cancer, and breast cancer, while in children they are mainly thyroid cancer, lung cancer, and breast cancer. Abdominal and pelvic CT are the main source of cancer in adults, while head CT predominates in children. CT scans harm minors more than adults; for infants under one year old who undergo CT scanning, the cancer risk from ionizing radiation is as much as 10 times that of other children.

The abuse of CT technology is already a global problem; our abuse of CT is almost on a par with our abuse of antibiotics. These latest medical technologies invented by humankind have brought us benefits but also enormous hidden dangers. Just as we need to be cautious about the use of antibiotics, we need to be cautious about CT. In the absence of clear indications, CT should be avoided as much as possible.

Ordinary people should also understand the hazards of CT radiation and avoid overusing CT. In real life, I often meet people who go to the hospital for a CT scan because they worry they may have a serious illness; so the abuse of CT is also related to the public's insufficient awareness of CT's hazards.

Although CT is very harmful, it must be acknowledged that, at critical moments, CT scanning can also save lives. Therefore, in life-threatening emergencies, CT scanning should not be overly rejected. It is just that in daily life, there is no need to over-rely on CT technology.