B3 - X-rays in medicine

B3 - X-rays in medicine

1. Used in hospitals for medical diagnosis. They are high frequency,short wavelength electromagnetic waves. Wavelength- roughly about size of diameter of an atom.

   • They are transmitted by (pass through) healthy tissue and are absorbed by denser material - bones and metal. They affect photographic wood in the same way as light which means they can be used to take photographs.
     • x-ray photographs can be used to diagnose medical conditions like bone fractures or dental problems. Images can be formed electronically using charge-coupled devices (CCDs). these are small silicon chips divided up into a grid of millions of identical pixels. They detect x-rays and produce electronic signals which are used to form high resolution images. The same technology is used to take photos in digital cameras.

2. Scans use x-rays. Computerised axial tomography (CT) scans use x-rays to produce high resolution images of soft and hard tissue. The patient is put in the cylindrical scanner and an x-ray beam is fired through the body from an x-ray tube and picked up by detectors on the opposite side. The x-ray tube and detectors are rotated during the scan. A computer interprets the signals from the detectors to form an image of a two-dimensional slice through the body. Multiple 2 dimensional CT scans can be put together to make a 3 dimensional image of the inside of the body.

3. Can be used to treat cancer. Can cause ionisation - high does will kill living cells so can be used to treat cancers like gamma. The x-rays have to be carefully focused and at the perfect dosage to kill the cancer cells without killing many normal cells.

   • To treat cancer: The x-rays are focused on the tumour using a wide beam. The beam is rotated round the patient with the tumour at the centre. This minimises the exposure of normal cells to radiation and so reduces the chances of damaging the rest of the body.

4. Radiographers take precautions to minimise radiation dose. prolonged exposure to ionising radiation can be very dangerous to your health. Radiographers who work with x-ray machines and CT scanners need to take precautions to minimise their x-ray dose. They wear lead aprons, stand behind a lead screen or leave the room while scans are being done. lead is used to shield the areas of patient's body that aren't being scanned and the exposure time is always kept to a minimum.