For the lucky, a check-up at the GP consists of nothing more sophisticated than a blood-pressure cuff, an icy stethoscope and a jar to pee in. For those with bigger problems, it can involve medicine's heavy artillery, from bedside ultra-sound devices to giant metal doughnuts that generate magnetic fields several times stronger than the Earth's.
Medical imaging has come a long way since Wilhelm Roentgen took the first X-ray of his wife's hand in 1895. Until then, doctors had no way to tell what was going on inside a living body. Autopsies (often illegal) could show them where organs were but not their functions.
If today's scanning technologies – X-ray, positron emission, magnetic resonance (MRI), computer-aided tomography (CAT), ultrasound and single photon emission – seem impressive, tomorrow's promise to be wondrous. Doctors will be able to detect not just large-scale structures but the microscopic interplay of proteins and enzymes as they react to diseases and treatments. Early screening will spot many problems before they become terminal. Diagnostic scans will predict which therapy will work best on a given patient, while follow-up images will determine whether all is going to plan.
From biotech start-ups to pharmaceutical and medical equipment giants, all want a piece of this new action, but one British-based company seems particularly well positioned. GE Healthcare, formerly Amersham, the first company to be fully privatised by Margaret Thatcher in 1982, was sold to the Americans in 2004 for $10bn. Back then, some in the City professed confusion about a company with a wide range of businesses lumped under the catch-all heading "diagnostic life sciences". They may still be nonplussed, but one set of numbers is crystal clear. GE Healthcare's sales have soared from $9bn in the year before the sale to $17bn in 2008.
"We're at a tipping point," the company said in a paper last May, comparing the coming transformation to that brought about by Thomas Edison when he invented the light bulb. "To take healthcare into the future, we do not have to wait for technologies that will be available in 2025. We need only look at the technologies we have today and act."
GE Healthcare's main campuses are scattered around the Chalfonts, a huddle of leafy villagesnorth-west of London. Dr Patrick Grove, then a 26-year-old organic chemist, established the company at Chilcote House in 1940 to refine radium for instrument dials on aircraft and ships. After the Second World War, it became a national centre for the development of radioactive materials and is still a licensed nuclear site.
Chilcote House is now the campus reception centre; security is tight and before visitors can enter some buildings, they must pin on a dosimeter to measure their radiation exposure. The office of Dr Marivi Mendizabal, GE Healthcare's head of discovery, is in a less glowing building. Still, the main room is divided in half by a glass wall inscribed with a double helix at waist height, with her lab on the far side. In a soft Spanish accent, Dr Mendizabal introduces a series of techniques, some developed in-house (the R&D budget is $1bn), some by partner companies, and others licensed from academia. They range from products approved for use to those still in early trials. What they share is a simple logic – better imaging means earlier diagnosis and more effective treatment.
While hardware has improved, the big change is in what Dr Mendizabal calls "wet science". One characteristic of chemistry, and particularly large biological molecules, is that they have counterparts that fit like keys in locks. Find the right key and it will latch on to a particular lock. It's the same technique used by the body's immune system to send antibodies after the antigens on invading cells. "It's not just antigens, though," she says. "This works on other molecules too."
Consider AH118635, a synthetic molecule invented at GE Healthcare that's so new it doesn't even have a catchy name yet. It reveals whether cancers are growing or not by latching on to a marker called integrin alpha 5 beta 3, which regulates blood-vessel growth. Most tumours are only alive near their surface; the centres die because they can't get enough blood, says Dr Mendizabal. AH118635, if it gets regulatory approval, will be able to tell how successful a tumour is at building new vessels, both by itself and after it's attacked with drugs designed to disrupt the process, such as Roche's Avastin.
Or take Hexvix, a chemical which accumulates in tumour cells and glows when exposed to blue light. Developed by PhotoCure, a Norwegian company, and distributed globally by GE Healthcare, Hexvix is already in clinical use. It increases the number of potentially cancerous cysts detected during optical bladder inspections, reducing the risk to the patient.
Another collaboration, this one with InSightec, combines two technologies, MRI and ultrasound, to replace the knife in treating uterine fibroids, a condition which often leads to hysterectomy. Instead, surgeons locate the fibroids on an MRI scan and focus a beam of high-intensity ultrasound to raise their temperature until it destroys the cells. The procedure takes just three hours and the patient is off work for a day, as opposed to four to eight weeks after a hysterectomy.
Even Roentgen's X-rays are becoming more useful. Nano agents, the first major development in X-ray technology since the invention of computer-aided tomography 30 years ago, promise to give doctors 1mm resolution of soft tissues as well as bones. The trick is to bundle up a tiny but dense ball of iodine atoms in a shell. Injected into the body, the iodine atoms act as tiny shutters, blocking the X-rays and revealing the internal shapes of organs.
Elsewhere in the Chalfonts, Robert Dann is showing off a virtual colonoscopy. Early treatment of colon cancer is 90 per cent successful, compared with 10 per cent if it is caught late. But the screening process is intrusive and unpleasant, so the take-up rate is low. The virtual colonoscopy turns a CAT scan of the large intestine into a movie, allowing the doctor to "fly" through the colon looking for colour-coded, pre-cancerous polyps. If this raises the screening rate from 30 to 100 per cent, more than 10,000 lives a year could be saved in the UK alone.
Saving lives is the popular measure for medical successes, but cutting costs is also important. The new wave of scanners promises to do this in two ways. By helping researchers evaluate drugs at an earlier stage, they reduce the cost of pharmaceutical development. And by catching diseases earlier and allowing more targeted treatments, they reduce direct clinical costs.
After generations in which technology drove the cost of medicine ever higher, it's about time the pendulum began to swing the other way.