other imaging techniques Flashcards
1
Q
x-ray
A
- electromagnetic wave that penetrate solid objects
- maybe absorbed or attenuated when they encounter objects of high density e.g bones or foreign objects
2
Q
x- rays
A
- produced using x-ray gun which accelerates electron into a metal target
- can tune the energy to hard or soft x-rays
- hard x-rays have greater penetrating power
- images are produced in a number of ways ( digital detection or film detection)
3
Q
x rays in security
A
- high energy hard X rays to penetrate things such as packaging or even metal cases
- used in the case of a technique known as backscatter X ray detection
- produce a full body scan of living humans,
identifying the presence of weaponry
4
Q
computerised axial tomography (CAT or CT)
A
- A CAT scanner consists of a X ray source and
detector normally housed in a torroid unit - The unit can take X rays from multiple angles
and these can be combined to form
3D images
5
Q
CT
A
- Systems such as SPECT (Single Photon Emission computed Tomography) use gamma irradiation
- PET (Positron Emission Tomography) uses no external irradiation whatsoever relaying on the breakdown of radioactive tracer isotopes
6
Q
Magnetic resonance imaging (MRI)
A
- MRI produces images that appear very similar to CAT, but in many ways
-MRI looks at soft tissues
At its most basic level, MRI works by placing an individual within a very strong oscillating magnetic field at a specific frequency
7
Q
ultrasound
A
Sonography- Imaging based upon ultrasound
- image internal structures within the body
- The process involves sending sound waves with a wavelength above 20,000Hz into the tissue
- It can also be used to examine for example the location of blood pooling and stiffness of tissue which at least have the potential to be used for determining time of death
