Zusammenfassung der Ressource
X-Rays in Medicine
- X-Ray images are used in hospitals for medical diagnosis
- X-rays are high frequency, short
wavelength electromagnetic waves -
wavelength roughly the same
diameter as an atom
- Transmitted by healthy tissue,
absorbed by denser materials like
bones and metal
- Affect photographic film in the
same way as light - can be
used to take photographs
- X-ray photographs can be
used to diagnose many
medical conditions - bone
fractures, dental problems
- Can be formed electronically using
charge-coupled devices (CCDs)
- CCDs are silicon chips about the
size of a postage stamp, divided
into a grid of millions of identical
pixels
- CCDs detect x-rays and produce
electronic signals - used to form high
resolution images
- Same technology as digital cameras
- CT Scans use x-rays
- Computerised Axial Tomography
- Use x-rays to produce high
resolution images of soft
and hard tissue
- Patient put in cylindrical scanner
- x-ray beam fired through the
body from an x-ray tube and
picked up by detectors on the
opposite side
- Tube and detectors are rotated
during the scan - computer
interprets the signals to form an
image of the 2D slice through the
body
- Multiple 2D scans can be put together to make
a 3D image of the inside of the body
- X-rays can be used to treat cancer
- X-rays can cause ionisation -
high doses will kill living cells
- Therefore used to stop cancer
- Have to be carefully focussed and
at right dosage to kill the cancer
cells without damaging too many
normal cells
- To treat cancer
- 1 - X-rays focused on the
tumour using a wide beam
- 2 - Beam rotated round the patient
with the tumour at the centre
- 3 - This minimises
exposure of normal cells to
radiation - reduces chance
of damaging the rest of the
body
- Radiographers take precautions to minimise radiation dose
- Prolonged exposure can be dangerous for your health
- 1 - Radiographers who work
with x-ray machines or CT
scanners need to take
precautions to minimise their
x-ray dose
- 2 - They wear lead aprons, stand
behind a lead screen or leave the
room while scans are being done
- 3 - Lead is used to shield areas of the
patients body that aren't being scanned,
and exposure time to the x-rays is
always kept to an absolute minimum