Radiation in Medicine: Powerful, Valuable - and Worth Understanding

Article by Dr. Donald Greig

A recent newspaper article highlighted research suggesting that past nuclear weapons testing may have contributed to millions of premature deaths worldwide. It was a sobering reminder of the long-term biological effects of ionising radiation.

Medical radiation is, of course, very different from nuclear fallout. It is controlled, targeted and used with the intention of diagnosis and treatment. Yet the article prompted me to reflect on an important topic in modern healthcare: how we use radiation in everyday medical practice — and why thoughtful use matters.

Radiation in Modern Medicine

Many common investigations use ionising radiation, including:

• X-rays

• CT scans

• Mammography

• Some cardiac imaging tests

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For the vast majority of patients, these tests are safe and medically appropriate. They save lives every day.

However, radiation exposure is cumulative. Unlike an injection or a blood test, radiation leaves a small biological footprint each time we are exposed. While the risk from any single scan is usually very low, repeated imaging over many years can increase lifetime exposure.

Some modelling studies suggest that approximately 3–5% of cancers in developed countries may be attributable to cumulative exposure from medical imaging. These are statistical projections across large populations, not predictions for individuals — but they are a reminder that radiation is not biologically neutral.

The goal is not to avoid imaging. The goal is to use it wisely.

Putting Radiation Dose into Perspective

Below is a simplified comparison of approximate radiation doses from common investigations. (Figures vary depending on equipment and protocols.)

A CT scan of the abdomen, for example, may expose a patient to the equivalent radiation of over 100 chest X-rays. That does not mean it should not be performed — but it should be performed when clinically justified.

The “Low Threshold” for CT Scanning

In modern healthcare systems, CT scans are sometimes ordered quickly for reassurance or defensive reasons. Patients may not always realise the relative radiation dose involved.

CT is an extraordinary diagnostic tool. In many cases — trauma, cancer staging, serious infection — it is indispensable.

But in other situations, alternatives such as ultrasound or MRI (which do not use ionising radiation) may be appropriate.

One of my roles as your physician is to ask:

• Is this test necessary?

• Will it change management?

• Is there a lower-radiation or non-radiation alternative?

• What is the cumulative exposure over time?

What About Breast Screening?

This is particularly relevant to my own practice, as breast care represents a significant part of the work we do.

Historically, earlier mammography systems (in the 1970s and 1980s) used higher radiation doses. Modern digital mammography uses substantially lower doses and far more refined targeting.

There is a very small theoretical risk of radiation-induced breast cancer from long-term repeated screening. However, extensive evidence shows that:

• Early detection of breast cancer significantly improves survival.

• The benefit of screening from age 40 onwards clearly outweighs the small radiation risk for most women.

• Modern techniques, including digital mammography and adjunct ultrasound where appropriate, minimise exposure.

In my own screening programme, we begin at age 40 with annual imaging and clinical examination. I am mindful of cumulative dose — and always balance vigilance with prudence — but I remain confident that early detection offers a far greater benefit than risk.

Screening is not perfect. But for most women, it is protective.

Informed Use, Not Fear

The purpose of this newsletter is not to create anxiety about medical imaging. It is to encourage informed discussion.

Radiation is a powerful diagnostic tool — one that has transformed modern medicine. Like all powerful tools, it deserves respect.

As your physician, I will continue to:

• Recommend imaging when it is clearly beneficial

• Avoid unnecessary exposure

• Consider non-radiation alternatives where appropriate

• Discuss risks and benefits openly

Healthcare works best when decisions are shared.

If you ever have questions about a recommended scan — its purpose, alternatives, or radiation exposure — please feel free to ask. Informed patients make better decisions.

Disclaimer: This newsletter is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider for any medical concerns.