Scans: Enhanced medical vision

The ability to look inside the human body without using a scalpel has revolutionized how we diagnose and treat illness and injury. By Brian Owens.

Uneven distribution

The number of scans per 1,000 people varies widely around the world (see Fig. 1). In some cases, such as New Zealand, the number may be underestimated because the data only include procedures paid for with public funds.

Figure 1

OECD HEALTH DATA 2013.

Rise of the machines

There has been a dramatic rise in the number of CT and MRI scans over the past decade in the United States.

Credit: OECD HEALTH DATA 2013.

Risky business

Some imaging procedures can expose patients to high levels of radiation, so the number and timing of scans must be carefully controlled over their lifetime.

Credit: HEALTH RISKS FROM EXPOSURE TO LOW LEVELS OF IONIZING RADIATION: BEIR VII PHASE 2 (2006).

Out of pocket

The cost of a single diagnostic scan can be steep, but can save money in the long run by eliminating the need for expensive surgery (see 'Positive feedback').

Credit: CMS PHYSICIANS FEE SCHEDULE 2013.

Positive feedback

As the use of pre-operative CT to diagnose appendicitis has increased, the number of false positives – and therefore unnecessary surgeries – has dropped to almost none.

Credit: RAJA, A.S. ET AL. RADIOLOGY, 256, 460-465 (2010).

Types of scans