P3.1 Medical Physics Flashcards
X-Rays image…
Send X-Rays though body part
Some X-Rays are absorbed (by bones)
X-Ray image on photographic film and darkens when developed
The bone cast a a shadow
Benefits of X-Rays…
See inside the body without having to cut it up
Drawbacks of X-Rays…
Can only see dense materials
Can cause cancer if the dose is high
Safety from X-Rays…
Lead- blocks the rays from the doctor and patient
Limited amount per year- on medical records
Ultrasounds are…
High frequency sound wave
Frequency is more than 20,000 Hz (higher than human hearing)
Reflected by changes in material density
Ultrasound image…
Waves from the emitter travel though materials (woman’s body)
Reflects when material (density) changes in surfaces
Time taken for emitted wave to be received- divide by 2
Distance = speed x time/2
Multiple waves at multiple angles at multiple distances plotted by machine
Benefits of Ultrasound…
Image of the foetus surfaces
Not ionising so no mutations and no cancer
Moving image
Doppler effect used to hear the heart beat
Drawbacks of Ultrasound…
The image is not clear
Needs to go on the mother’s skin
Uses of Ultrasound…
Pre natal scans
Removing kidney stones
CT/CAT scans are…
X-Rays
Multiple angles and multiple X-Ray exposures
Higher dosage than a single X-Ray
CT/CAT scan image…
Multiple images at overlapping angles
Processed by computer
More detail
3D image can be explored on the computer
CT/CAT scan benefits…
Very detailed can be explored in a computer
Practise surgery
CT/ CAT scan drawbacks…
Much higher dosage of X-Rays
Can cause mutations and cancer
X-Rays are…
Electromagnetic waves High frequency High energy Cause damage to DNA (cause mutation and cancer) Absorbed by denser materials
