Before the advent of photography, medical texts favoured detailed illustrations of medical conditions and procedures—until technology gave us new ways of visualising the body.
The medical community was an early adopter of photographic technology following its invention in the mid-1800s. Photography was used primarily to document the visible symptoms of patients with particular medical conditions. But for several decades, medical texts continued to favour hand-drawn illustrations of diseases and procedures because a skilled artist was able to capture detail more accurately than a photograph.
In modern medicine, still and video photography are still used as diagnostic tools and to document case histories. But the 1900s saw an explosion of new technologies that provided unprecedented views of the internal body and aided diagnoses that were not possible before.
Digital photography continues to play a role in medicine through documentation, research and education. Video cameras are commonly used to look inside the body, most often in the form of endoscopes.
An endoscope consists of thin tubes with a powerful light and tiny camera at the end. The length and flexibility of the endoscope depends on the part of the body the practitioner needs to investigate. For example, an endoscope designed to examine the joints is often rigid. However, one used to view the inside of the colon is long and flexible.
Capsule endoscopy is a procedure that uses a tiny wireless camera to take pictures of the digestive tract. It helps practitioners see inside the small intestine—an area that isn't easily reached with a traditional endoscopy procedure.
The camera sits inside a vitamin pill-sized capsule that is swallowed by the patient. As the capsule travels through the digestive tract, the camera takes thousands of pictures that are transmitted to a recorder worn by the patient.
Endoscopy allows medical practitioners to scan for tumours, to investigate symptoms or confirm a diagnosis and to help surgeons prepare for procedures such as keyhole surgery.
X-rays were the first technology that made it possible to see inside the body without having to open it up. They were discovered by German physicist Wilhelm Roentgen (1845–1923) at the end of the 1800s and had an immediate impact on anatomical study and diagnostics.
Medical practitioners used early X-ray images to locate broken bones or foreign objects lodged in the body, such as bullets.
How to create an x-ray image
X-rays are a high-energy, invisible, form of electromagnetic radiation. Like visible light, they are reflected by some objects and absorbed to varying degrees by others.
When a body is placed between an X-ray source and a photographic (or fluoroscopic) film or screen, an image forms. Denser body parts, such as bones, absorb more X-rays, creating lighter areas on the image. Softer tissue allows X-rays to pass through, leaving dark shadows on the image.
At the heart of an X‑ray machine is a vacuum-sealed glass cylinder containing a pair of electrodes. When electricity is sent through the tube, X‑rays are released at the positive electrode.
X-ray images were also utilised outside medicine. Between the 1920s and 1960s, for example, shoe-fitting fluoroscopes (also known as pedoscopes) could be found in many shoe shops. A child trying on new shoes would stand on the footpad of the machine while they, a parent and the sales assistant looked through viewing portholes at a continuous X-ray image. The fluorescent image would show the bones of the feet and an outline of the shoes to reveal how well they fitted.
But in the late 1920s, evidence began to emerge which showed that large doses of X‑ray radiation were harmful. As a result, both patients and practitioners had to be protected from over-exposure. Machines were shielded, radiologists wore protective clothing, and non-essential exposure to X-rays, such as shoe-fitting machines, were phased out.
By the 1930s, radiology had become a medical specialism and X-ray images were an essential tool in hospitals, the military and public health programmes. Army recruits were X‑rayed for chest conditions such as tuberculosis, and in the 1940s mobile X-ray units travelled around the country performing mass civilian screening for the disease.
X-ray images were also used during pregnancy until the 1950s, when British physician Alice Stewart (1906–2002) demonstrated a link between foetal X‑rays and childhood cancer. Conversely, targeted X-ray radiation is now used to kill cancerous cells in the body in the form of radiotherapy.
Body scanning technologies
Scanning technologies collect readings from the body and use a computer to process the data into visual images. The readings can be taken from a variety of sources:
X-ray transmission through the body
The body’s own electrical activity
Minute radio wave signals at the atomic level
Echoes of high frequency sound waves.
Scanning technologies have various medical functions and provide medical practitioners with different kinds of information.