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Explain the effect of age on radiation risk


Children much more at risk due as cells are dividing, growing
Older people have negligible risk as won't see effect


What is the main justification for radiographs?

Benefit to patient must outweigh detriment


What are the 5 justifications of radiographs?

1. Findings and availability of previous X-rays
2. Alternatives: little or no radiation w/ same objective
3. Total benefit to patient
4. Risk: radiation risk associated w/ examination
5. Objectives in relation to history and examination


Describe the optimisation and limitation of radiographs

Optimisation: patient doses should be red. to as low as reasonably practicable

Limitation: equivalent dose to patient should not exceed limits recommended by ICRP


What are the 4 areas where radiation dose can be reduced?

1. Equipment
2. Clinical decision
3. Practical technique
4. Diagnostic interpretation


What are the 5 equipment factors that can red. dose?

1. Focus to skin distance: 15-20cm
2. Rectification: AC-DC, more photons, lower dose
3. Aluminium filtration: remove low energy photons
4. Rectangular collimation: rectangular sensor to rectangular film
5. Film and sensors: digital vs conventional


Describe conventional and digital radiographs films

Conventional: can't be exposed to light, long time to develop, develop in dark room

Indirect digital: phosphorus plate, quicker, use reader to develop

Direct: charge-coupled device, instant, no lag time, special holders, bulkier

Digital red. dose by 50% but may require more retakes (less careful as so quick and easy)
Latitude (range of exposures image will be captured) wider for digital which could inc. dose as high quality images obtained at extremes thus don't check everything working


What are the 6 remits for radiographs?

1. Caries diagnosis
2. Developing dentition
3. Endodontics
4. Periodontal assessment
5. Implant dentistry
6. Good practice


What are the 3 practical technique factors for taking radiographs?

1. Aligning tube w/ film
2. Lead aprons: no justification, discouraged for panoramics
3. Pregnancy: justification, optimisation, delay, lead for physiological reasons


Explain the controlled area

Area that only exists when X-rays being taken: indirect beam of X-ray (when no shielding or sufficient distance) and 1.5m from beam and patient in all other directions

If distance is not sufficient shielding must be used