Intro to Radiology Flashcards
What important legislation is in place regarding Ionising radiation?
ionising radiation regulations 2017
ionising radiation (medical exposure) regulations 2017
What is a radiograph?
An image produced by x-rays passing through an object and interacting with photographic emulsion on a film
What is affected if a digital image is being formed?
A sensor or phosphor plate
In dentistry, what tissues are of interest in regards to radiographs?
Mineralised and demineralised tissue
What would demineralised tissue on a dental radiograph indicate?
Caries and other dentally related disease
Q
What type of radiograph matches the description:
- Film/ sensor is placed inside the mouth next to the area of interest
- Radiation source is directed at the areas from an external position
Intra oral radiograph
What are the three main types of intra-oral radiograph?
periapical
bitewing
occlusal
What type of radiograph matches the description:
- Nothing placed inside the mouth
- Radiation source and image receptor are both extra-orally positioned
Dental Panoramic Tomography (DPT)
What can DPT also be referred to as?
OPT and OPG
What is contained within the nucleus of an atom?
Protons and neutrons
Are protons +ve, -ve or no charge?
+ve charge
Are neutrons +ve, -ve or no charge?
No charge
Are electrons +ve, -ve or no charge?
-ve charge
How many electrons are in the K shell (closest to nucleus)?
2
How many electrons are in the L shell of an atom?
8
What can move from shell to shell but cannot exist between shells?
Electrons
Which electrons in an atom will have the greatest binding energy?
Outer electrons
What is an atom with the same number of protons but a different number of neutrons referred to as?
An isotope
What is a radio-isotope?
An isotope with unstable nuclei which undergoes radioactive disintegration
What is a negatively charged ion called?
An anion
What is a positively charged ion called?
A cation
What type of particles have these features?:
Made up of 2 protons and 2 neutrons
- large size
- +ve charge
- slow speed
- penetrate only 1-2mm in tissue
- 4-8 MeV energy
- extensive ionisation
Alpha particles
What type of particles have these features?:
- Electrons
- small size
- -ve charge
- fast speed
- penetrate 1-2cm in tissue
- 100keV-6MeV energy
- ionisation
Beta particles
What type of rays is part of the electromagnetic radiation spectrum, has no size or charge and has very fast speed , passing through tissues?
Gamma rays
What type of rays are x-rays in dentistry almost identical to? And what is the slight difference?
Gamma rays, except x-rays have lower energy values
When is ionisation a problem?
When it occurs in living cells, can cause damage to DNA leading to tumours and cancer
What size of wavelength do gamma rays have?
Small wavelength
Define the electromagnetic spectrum
A stream of photons that have no mass
What is measured in electron volts (eV)?
Energy
What is measured in cycles per second or hertz?
Frequency
What is measured in metres or nanometres?
Wavelength
One cycle of a wave length is what shape?
S-shaped
What is the number of wavelengths that travel every second the same as?
Frequency
What is the wavelength spectrum for visible light?
400-700nm
What is the domestic electricity supply?
220/240 volts
50 hertz
What is the SI unit of potential difference? And what does it measure?
Volt
It measures potential difference or electromotive force
Describe how a circuit of electricity occurs
Current passed along wire by vibration if electrons
Passes from -ve to +ve
Battery has a direct current
Electricity supply is alternating
In the example of an old-fashioned electric fire, how is heat given off?
By means of convection and radiation
What electrons produce heat?
Vibrating electrons
what is heat produced proportional to?
Current and voltage
