1 of the greatest discoveries in civilization was that of fire. Based on current evidence, our cousins Homo erectus may have used fire even before Homo sapiens some 1,000,000 years ago. Those in our genus (Homo) found fire for food preparation a survival advantage, aiding in our ability to provide calories above and beyond what was otherwise available. Later, the thermal properties of fire were used to develop life-sustaining technologies. One example would be using heat to create pottery for storage of food and other items such as bronze. However, with all its potential good, fire can obviously be quite deadly. With ancient villages and other densely concentrated structures made of flammable materials, a large enough fire could destroy homes and other major assets as well as injure/kill humans in its path. With the purposeful use of fire, did the extended human family foresee its risks as well as its benefits?
Switching now to the purely medical, 1 of the greatest developments in modern medicine was the discovery of imaging technologies to distinguish diseased tissue from healthy tissue. As an ill patient, one of the least favorite things to hear at the bedside is “Well, we could always do exploratory surgery”. With the exception of certain cases of trauma, this rarely happens anymore because of these amazing imaging techniques available. Magnetic resonance and ultrasound involve very little risk to the patient because they do no damage to the tissue. In distinction, x-rays have the ability to damage tissue, especially DNA (the critical blueprints of life), by bumping electrons away from their atoms which renders the remaining material ionized. With damaged DNA to guide production of critical enzymes for the body, the body can no longer repair itself or change with new environmental demands. That often leads to debility and death.
Frequently, in a hospital and other places, one will often hear about either a CT scan or CAT scan. CT stands for computed tomography and CAT stands for computed axial tomography. The terms are interchangeable.
As mentioned above, x-rays damage tissue, to an extent. A single image chest x-ray has relatively low radiation. A mammogram has an intermediate amount. A CT scan, e.g. of the head, quite a bit more. The values are generally held to be 0.1 mSv, 0.4 mSv, and 2.0 mSv respectively. Please note that due to background radiation, we all absorb 3 mSv each and every year.
CT scans, 1 of the greatest advances in medical imagery, are also 1 of the greatest sources of ionizing radiation. In 1980, 3,000,000 CT scans done in the United States. In 2023, there were 93,000,000 CT scans done (Author Rebecca Smith-Bindman, MD, et al., Projected Lifetime Cancer Risks from Current Computed Tomography Imaging, JAMA Internal Medicine, published April 14, 2025). Thus, there has been a 30 fold increase in the interval use CAT scans.
There are many reasons for the massive increase in CT scanning. As noted above, a CT scan is a noninvasive way of imaging internal contents of the body. The quality of the images has improved substantially year over year. The length of time a given scan requires has dropped significantly. Even the amount of ionizing radiation per scan has improved to an extent in recent years (although this will be further discussed later in this article). Unfortunately, all of these improvements seem to have softened the threshold at which physicians order CT scans. The author of this article has witnessed a trend in the use of CT scans where they are ordered in lieu of clinical common sense or even as a means to mitigate against potential criticism by documenting clinically obvious diagnoses. An example of both would be a patient with 2 days of escalating right lower quadrant abdominal pain which was initially diffuse and centering around the belly button and then made its way to “McBurney’s point” (a reference point for the appendix) with findings on examination of tenderness, guarding, and rebound. The CT scan in that type of situation would be redundant and unnecessary (CT scans are generally most useful when the “a priori” [pretest] chance of disease is 50%). Yet, because of its easy availability, the threshold of ordering CT scans is dropping. Physicians especially and even the general public should not allow this.
Specifically, CT scans with marginal indications should not be allowed because more and more data indicate that, while CT scans are critical tools in the clinical toolbox, they are also potentially very dangerous. Referring back to the article above (Projected Lifetime Cancer Risks from Current Computed Tomography Imaging), these 93,000,000 CT scans done on 62,000,000 patients in 2023 will lead to 103,000 future cancers. This is quite stunning. In dealing with these cancers, it must be noted that possibly, the CT scans given were sometimes more deadly than the presumed pathogen for which they were ordered. Cancer has a huge impact on the patient and society in general, potentially leading to death and debility, suffering, and financial hardship for the patient. This does not cover the cost to society when a worker cannot work. Many sufferers of cancer elect not to return to work and employers must replace a trained worker.
Very sadly, CT scans administered to the pediatric population seems to be disproportionately toxic to that subpopulation. This seems to be due to 2 factors. Factor one is that the pediatric population has more years of life for the carcinogenic effects of radiation to express. Factor 2 is that younger patients are more metabolically active as they grow which makes them more “radio-sensitive”, i.e. vulnerable to the damage caused by x-rays.
So, how can this problem of excess radiation from CT scans be addressed? Clinically, physicians need to weigh better the pros and cons of the test. If the patient presents with an uncomplicated headache, it is not necessary to do a CT scan of the brain. If the patient presents with a more complicated headache, might an MRI of the brain be a better test (MRIs have no ionizing radiation)? If the patient presents because of right lower quadrant abdominal pain is highly suggestive of appendicitis, is a CT scan of the abdomen even necessary (a positive CT scan for appendicitis would add little information, a negative scan would be considered a “false negative” and ignored anyway). In parallel, the technology for CT scans has by no means been fully optimized. Historically, absent the computational power to reconstruct images generated by a CT, the patient would be exposed to more radiation to improve the image. Now with improving image reconstruction algorithms and better x-ray detectors built into the CT, radiation dosage can be further reduced.
In Greco-Roman mythology, the Titan Prometheus stole fire from the Olympians and gave it to mankind. He was the embodiment of intellect and reason. Indeed, the proper translation of his name, Prometheus, means “forethought”. Sadly, without proper guidance, it becomes easy for physicians to order tests without decisive forethought, i.e. weighing the pros and cons of the test. This needs to be borne in mind consistently. As suggested numerous times above, CT scans are amazingly powerful tools but, as the title of this article says, with great power comes great responsibility.