X-rays
- Created by: edsutton160501
- Created on: 28-10-16 19:56
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- X-rays
- Properties of X-ray waves
- X-ray waves have a very short wavelength.
- X-ray waves are transverse waves.
- X-ray waves oscillation of the particles are perpendicular to the direction that the wave travels.
- X-rays are part of the electromagnetic spectrum.
- X-rays follow the inverse square law: the further the source of radiation is away from the point at which it is being measured the lower the dose.
- For example when the distance from the source is doubled, The intensity of radiation is reduced by four times (two squared)
- X-rays follow the inverse square law: the further the source of radiation is away from the point at which it is being measured the lower the dose.
- X-ray waves have high frequencies.
- Uses of X-rays
- Charge-coupled devices can be used to check for bone and dental abnormalities.
- Thermal emission can create X-ray waves. An X-ray machine is made of an evacuated tube which contains a cathode and anode. The cathode is a wire filament which when heated emits electrons.
- 2.When the electrons hit the anode kinetic energy is transferred to thermal energy. during this process some energy is also transferred into X-ray waves.
- 1.When the potential difference between the anode and cathode is big, electrons are accelerated from the cathode to the anode.
- The higher the potential difference between two electrodes the more energy the X-ray wave produced carries which means the wave is more ironizing.
- The kinetic energy of an electron can be calculated using the equation: kinetic energy(J)= 1/2mass(kg)*velocity(m/sSquared)
- The size of the current in an X-ray machine can be calculated using the equation: current(A)= number of particles per second(1/s)*charge of each particle(C)
- 2.When the electrons hit the anode kinetic energy is transferred to thermal energy. during this process some energy is also transferred into X-ray waves.
- X-ray waves are directed at the area of the patients body which is being checked. The images are formed on a CCD (Charge-coupled device) which means they can be recorded and stored more easily.
- Parts of the body which are more dense e.g. bones, allow fewer X-ray waves to pass through them and therefore appear paler on x-ray images.
- Parts of the body which are less dense e.g. skin, soft tissue allow more X-ray waves to pass through them and therefore appear black on X-ray images.
- In the past, white photographic paper needed to be placed behind the area of the patients body that was being checked in order for an X-ray image to be produced because CCDs were yet to be invented.
- Thermal emission can create X-ray waves. An X-ray machine is made of an evacuated tube which contains a cathode and anode. The cathode is a wire filament which when heated emits electrons.
- CAT (Computer Axial Tomography) scanners can be used to check cross-sections in the body.
- CAT scanners used 2D X-ray images to produce a 3D image of a cross section.
- Organs made of soft tissue e.g. intestines need to be filled with a contrast medium that absorbs X-rays in order to show up on an X-ray image.
- CAT scanners used 2D X-ray images to produce a 3D image of a cross section.
- Fluoroscopy can be used to check the digestive system is functioning properly.
- 2. Multiple images are taken to produce a short film of the moving internal structure.
- 1.Fluoroscopy consists of a patient standing between and X-ray source and a fluorescent screen
- 2. Multiple images are taken to produce a short film of the moving internal structure.
- X-rays can be used to identify and treat cancerous tumours.
- A high energy X-ray wave is directed at the cancerous tumour until the cancerous tumour dies from the radiation.
- Charge-coupled devices can be used to check for bone and dental abnormalities.
- Advantages of X-ray waves
- X-rays are more detailed and are therefore more reliable when searching for small abnormalities.
- Disadvantages of X-ray waves
- X-ray waves are ironizing and can therefore damage living tissue.
- As a result workers who are exposed to x-ray waves frequently should use lead screens to shield them from the harmful waves.
- As a result patients are limited to the number o X-rays they can have to reduce exposure to radiation.
- As a result pre-natal scans are performed using ultrasound instead of X-rays because ultrasound is less harmful.
- Contrast medium must be used in order for soft tissue to show up on X-ray images.
- X-ray waves are ironizing and can therefore damage living tissue.
- Properties of X-ray waves
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