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Detecting Disease – Finding Cures
Many people thought a miracle had happened when, over a century ago, Wilhelm Conrad Röntgen used x-rays to look inside a hand and make the bones visible. Others thought it was magic. In fact it was neither: x-rays are an electromagnetic phenomenon. When the body is exposed to x-rays, different types of tissue absorb the radiation to different degrees. The radiation that emerges on the other side of the body is captured on a film.
Even today, x-rays are still used to make useful diagnoses. The classic imaging method is nowadays flanked by other techniques such as ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography (PET).
Contrast media are often used during these diagnostic procedures to enhance the image of the structures and functions inside the body. Bayer Schering Pharma is a pioneer in the development of these substances. The company brought the first iodine-based contrast medium onto the market as long ago as 1931. It remained the medium of choice for imaging the kidneys, bladder and blood vessels for decades.
In 1988 Bayer Schering Pharma produced another pioneering achievement in diagnostic imaging when it brought the first MRI contrast medium onto the market. MRI works using a completely different principle to x-rays, CT and ultrasound. The images from within the body are generated by a complex interaction between a powerful magnetic field and radio waves.
The developers originally thought that magnetic resonance imaging would be effective without special contrast media, but they soon changed their minds once they started using the product from Bayer Schering Pharma. It achieved a better contrast and expanded the uses for the technology. Today MRI is the diagnostic method of choice for disorders of the central nervous system, the locomotor system and the internal organs. MR technology is also used in another method, magnetic resonance angiography (MRA). This technique provides information on what is happening inside the blood vessels and also uses a contrast medium. For example, a product known as a blood pool contrast medium which is based on the element gadolinium produces brilliant images of the blood vessels. The advantage of these products compared with conventional MRI contrast media is that the radiologist needs to give the patient just one injection and then has a large window of about one hour during which he can image all the blood vessels from the abdominal aorta to the tiniest vessels in the big toe. This method is used to diagnose vascular disease in the abdominal cavity and the extremities.
Recent work in diagnostic imaging has been concentrating on the further development of existing contrast media for new applications and on the development of new substances for applications such as molecular imaging. This type of substance is capable of identifying specific molecules typically associated with a disease. Scientists hope that it will be possible to make an early and precise diagnosis at the cellular or molecular level before the patient develops symptoms. Usually, the earlier a diagnosis is made, the better the chances of a cure or relief. Molecular imaging could bring particular benefits to patients in tumor diagnosis and in the early detection of diseases of the central nervous system.
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