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| Roentgen 1895; 1st took 25 minutes; process >100 yrs. old |
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| has weight and mass, travels in straight lines; inc. alpha & beta particles, cathode rays, electrons, protons and neutrons |
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| Electromagnetic Radiation |
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| no mass or weight, no electrical charge, travels at the speed of light as a particle and a wave; magnetic field is at right angle to electric field |
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| stronger, more penetrating waves |
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| (+) ; where x-rays start; tungsten target, focal point - copper stem dissipates heat |
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| (-) ; tungsten filament, produces electrons when heated; molybdenum cup- focuses and directs electrons |
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| DC; Rectification: the conversion of AC to DC; 60 impulses per second |
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| number of electrons at the filament; measured in MA (milliamperes)1/1000 of an ampere |
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| measurement of electrical force/speed from cathode to anode; measured in Kv (kilovolts)- 1000 volts |
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| Electrons strike tungsten target, kinetic energy turns to 1% x-rays and 99% heat |
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| Bremsstrahlung (General)Radiation |
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Definition
| electrons brake as they near nucleus (suddenly halt); affects nucleus; occurs most of the time; 70% of radiation produced; no ionization |
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| dislodge inner shell electron from tungsten target; occurs when 70 kVp or higher is used; 30% of radiation produced; ionization occurs |
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| x-rays produced at the target; "useful beam" |
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| x-rays produced when primary radiation interacts w/ matter; ex: from cheek to film |
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| x-rays that are deflected from matter |
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*No interaction- responsible for densities (raadiolucency)
*Absorption (photoelectric effect)- white areas (crowns & fillings)
*Scatter- Compton (ionize) and Coherent (not ionized) |
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Definition
| mean energy/penetrating ability; affected by kVp and filtration; higher kVp = more penetration, thus shorter wavelength |
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| degree of overall darkness of film; increased kVp = higher density; decreaased kVp = lower density |
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| Factors that affect density |
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Definition
| kVp; mA; exposure time; subject thickness; filtration |
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| differentiates between colors on a film; affected by kVp and filtration; *decrease in kVp produces high contrast (good for detection & progression of caries); short scale- blacks and whites * increase in kVp produces low contrast (good for detection of periodontal disease) long scale- many shades of gray |
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Definition
| measured in impulses; 60 impulses per second |
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| Amperage (dental units set at) |
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