1 Imaging in medicine
Many of the important advances in medicine in recent decades have arisen from our progress in understanding the structure and workings of the human body.
Diagnosis of illness is aided by the ability to obtain detailed information about the structure of a particular organ or part of the skeleton to see if it is abnormal, damaged or malfunctioning in some way. For example, a growth may prevent the passage of food and waste through the gut, or fatty deposits may cause problems with blood circulation.
To obtain this information, the abnormal or diseased tissue has to stand out from those around it – its properties have to be sufficiently different from the properties of normal tissue or surrounding matter, to be distinguished by the techniques chosen for investigation.
Can you list a few medical imaging techniques you are familiar with?
X-ray, magnetic resonance imaging (MRI) and ultrasound.
There are two main types of imaging.
- Anatomical imaging, in which structures are examined by exploiting differences in the physical or chemical properties of the materials in the body – for example, between bones and soft tissue, or between normal breast tissue and breast tumour.
- Functional imaging, in which, for example, a substance can be injected into the body and its distribution tracked and monitored, to assess the functioning of a particular organ or system.
You will focus on the first of these – anatomical imaging – in the next two sections where you will look at X-ray and MRI.