The Hidden Risk: Reassessing the Long-Term Cancer Impact of CT Scans

In modern medicine, few tools are as ubiquitous—or as trusted—as the computed tomography (CT) scan. Fast, precise, and widely reimbursed, CT imaging has become a go-to diagnostic solution across emergency rooms, cancer centers, and primary care offices alike. But as its usage has soared over the past two decades, so has a sobering question: Can the very technology designed to diagnose illness quietly contribute to it?

Recent studies suggest the answer, at least in part, may be yes.

A 2025 study published in JAMA Internal Medicine estimated that more than 103,000 future cancer cases in the United States could be linked to CT scans performed in a single year1. That figure—up to four times higher than earlier projections—represents approximately 5% of all annual cancer cases. Particularly troubling is the study’s finding that children under the age of one face a relative cancer risk ten times higher than other groups, especially after head scans. The research points to a conclusion long acknowledged in radiation oncology: ionizing radiation, even in modest doses, is not without consequences.

As a physician, I believe it’s time to reframe the conversation around diagnostic imaging. We must be honest about the risks, particularly for our youngest and most vulnerable patients. We must also confront how deeply ingrained systems—reimbursement protocols, outdated medical training, and risk-blind routines—have made it harder, not easier, to prioritize safer diagnostic tools.

Radiation: Necessary, But Not Benign

Ionizing radiation from CT scans can damage DNA at a cellular level, directly breaking the double-helix and triggering mutations that either activate cancer-driving oncogenes or suppress protective tumor-fighting genes. It’s a cumulative risk: each exposure adds to the body’s total radiation load, which becomes more dangerous over time, especially when scans begin in childhood.

This is not abstract theory. Survivors of Hiroshima, Nagasaki, and Chernobyl demonstrate the devastating effects of high-dose exposure. CT scans, while lower in dose, still fall into the category of ionizing radiation. For every one millisievert (mSv) of exposure, cancer risk increases 5–10%. And while the average background radiation exposure globally is around 2.4 mSv annually, Americans receive roughly 6.2 mSv—largely due to medical imaging2.

In my clinical experience, patients and physicians alike often underestimate that risk. CT scans are prescribed so routinely that their hazards feel negligible. But routine doesn’t mean risk-free. Even low-frequency exposures, when repeated, become a meaningful concern. Particularly alarming is the use of CT imaging in infants, whose developing tissues are far more vulnerable to genetic damage. When radiation exposure begins early, the cumulative lifetime risk soars.

Reimbursement and Routine: What Drives Overuse

Why do we default to CTs despite safer options? In short: it’s fast, it’s familiar, and it’s covered.

CT scans are widely reimbursed by insurance with minimal scrutiny, especially when ordered according to standard protocols. Hospitals know these scans won’t trigger denials or financial loss. For overworked physicians and administrators, it’s an easy yes. Safer alternatives—such as MRI or QT ultrasound—may require pre-authorizations, face reimbursement hurdles, or fall outside approved diagnostic guidelines.

In this system, protocols become gospel. Insurance companies don’t pay for innovation—they pay for conformity. That stifles critical thinking and punishes clinicians who want to reduce harm but are bound by reimbursement logic.

At the Williams Cancer Institute, we’ve seen firsthand how rethinking this paradigm can help. For example, instead of relying exclusively on repeated CTs to monitor tumor progression, we often alternate modalities. A patient may start with a PET-CT, but we’ll follow up with an MRI, or even ultrasound, to reduce cumulative radiation exposure. This integrated approach preserves diagnostic accuracy while minimizing long-term harm. But we shouldn’t be the exception—we should be the model.

Safer Doesn’t Have to Mean Slower

MRI scans, which use magnetic fields rather than ionizing radiation, are an effective and safe alternative for many diagnostic needs. QT ultrasound, another emerging technology, offers radiation-free breast imaging that avoids the physical compression and radiation of traditional mammography—particularly beneficial for patients with suspicious lesions. Research has shown that preoperative manipulation and radiation of tumors can increase circulating tumor cells, potentially exacerbating the very disease we seek to detect.

Unfortunately, these alternatives face systemic barriers. For instance, the innovative company Prenuvo offers full-body MRIs with fast turnaround times and no radiation—but operates outside the traditional insurance system due to reimbursement constraints. QT ultrasound, while promising, is still viewed as novel despite its diagnostic potential. These innovations thrive outside the mainstream because the mainstream often refuses to adapt.

And this speaks to a larger systemic issue: medicine today rewards standardization over innovation. Yes, protocols can promote safety and consistency—but they can also discourage progress. Creativity in diagnostic imaging shouldn’t be penalized. It should be incentivized.

Reclaiming the Doctor-Patient Bond

The deeper issue is this: healthcare has shifted from a doctor-patient relationship to a protocol-payer relationship. Doctors are no longer just caregivers; they are often beholden to hospital policies, government agencies, and insurance rules that dictate their every move. And patients, sensing this shift, are losing trust. A recent JAMA Network Open survey found that only 40% of Americans trust physicians and hospitals—a sharp decline from past decades3.

When physicians are forced to prioritize compliance over care, and patients are left out of critical decisions, medicine suffers. We must return to our primary purpose: to serve patients, not systems.

That begins in medical education. We need to teach physicians not just what to think, but how to think—critically, ethically, and independently. Innovation should be a core tenet of clinical training, not an elective. We also need to reform reimbursement structures to support safer, smarter diagnostics—not just faster ones.

Looking Ahead: Innovate, Elevate, Empower

The future of diagnostic imaging lies in a three-part vision: innovate, elevate, and empower.

We must innovate by embracing new tools and approaches that reduce risk and improve outcomes. We must elevate our standards of care beyond routine to reflect what’s truly best for patients. And we must empower both doctors and patients to make informed, individualized decisions that weigh long-term impact—not just short-term convenience.

CT scans will always have a role in medicine. But they must be used with discernment, transparency, and respect for the full picture—not just the image.

References

1. Smith-Bindman R, Chu PW, Azman Firdaus H, et al. Projected Lifetime Cancer Risks From Current Computed Tomography Imaging. JAMA Internal Medicine. 2025;185(6). doi:https://doi.org/10.1001/jamainternmed.2025.0505

2. Radiation Sources and Doses | US EPA. US EPA. Published April 15, 2015. https://www.epa.gov/radiation/radiation-sources-and-doses?utm

3. ‌Perlis RH, Ognyanova K, Ata Uslu, et al. Trust in Physicians and Hospitals During the COVID-19 Pandemic in a 50-State Survey of US Adults. JAMA Network Open. 2024;7(7):e2424984-e2424984. doi:https://doi.org/10.1001/jamanetworkopen.2024.24984