X-Ray Basics
X-rays travel at the speed of light in a vacuum
What is the property of x-rays?
Negatively charged electrode
What is the cathode ?
Controls number of electrons
What is mA?
ALARA
What is as low as reasonably achievable?
Inverse square law
What law governs distance and exposure?
X-rays are a form of electromagnetic radiation
What are x-rays?
Thermionic emission
What is a electron boiling from filament?
Image blackness
What is radiographic density?
Ionization of cells
What causes radiation injury?
Exposure drops to 1/4
What happens when distance doubles?
X-rays cannot be focused by a lens
What is a property of x-rays?
Positively charged rotating target
What is the anode?
Controls beam penetration
What is kVp?
Thyroid and eyes
What tissues are most sensitive ?
0.5 mm lead apron
What is standard lead protection?
X-rays can ionize matter
What is a property of x-rays?
0.6% converts to x-rays
What is x-ray production efficiency?
15% kVp doubles density
What is the 15% rule?
Threshold-based effects
What are deterministic effects?
5 REM/ year
What is the occupational dose limit?
X-rays cause crystals to emit light
What is fluorescence?
99.4% converts to heat
What happens to most energy?
mA x time
What is mAs?
Random long-time effects
What are stochastic effects?
15 Gy
What is a sentinel patient dose?