X-Ray Physics
What is the fundamental unit of matter?
Answer: Atom
What does ALARA stand for?
Answer: As Low As Reasonably Achievable
What happens if the PID is too far from the patient?
Answer: The image becomes lighter due to reduced radiation intensity.
Who discovered x-rays?
Answer: Wilhelm Conrad Roentgen.
What is the term for the period between radiation exposure and the appearance of biological effects?
Answer: Latent period.
What charge do electrons carry?
Answer: Negative
What piece of protective equipment should always be used on a patient?
Lead apron and thyroid collar
What is the term for the variation in shades of gray on a radiograph that allows differentiation between structures?
Answer: Contrast.
What year were x-rays discovered?
Answer: 1895.
What is the term for the total amount of radiation energy absorbed by a tissue?
Answer: Radiation absorbed dose (RAD) or Gray (Gy).
What is ionization?
The process by which an atom loses or gains an electron, becoming unstable
What is the term for the device used to restrict the size and shape of the x-ray beam, reducing patient exposure?
Answer: Collimator
What is the term for the overall darkness of a radiograph?
Answer: Density.
What is the term for the science or study of radiation as used in medicine?
Answer: Radiology
What is the term for the maximum amount of radiation a person can be exposed to over a specific period without significant risk?
Answer: Maximum Permissible Dose (MPD)
What happens when x-rays disturb orbiting electrons?
It creates an ion, which can lead to biological damage.
How far and at what angle should the operator stand from the x-ray source during exposure?
At least 6 feet and at a 90-135 degree angle.
What is the effect of increasing kilovoltage (kV) on contrast?
Decreases contrast, producing more shades of gray.
What is the term for the recording medium used in dental imaging, such as x-ray film, phosphor plates, or digital sensors?
Answer: Image receptor.
What is the term for the cumulative effect of repeated radiation exposure over time?
Answer: Cumulative radiation exposure.
Name the four possible interactions of x-rays with matter.
No interaction, Photoelectric effect, Compton scatter, Coherent scatter
What is the recommended total filtration for an x-ray unit operating above 70 kVp?
2.5 mm aluminum.
If a radiograph appears too light, what exposure setting likely needs to be adjusted?
Answer: Increase mA, kVp, or exposure time.
What is the difference between primary, secondary, and scatter radiation?
What is the MPD (Maximum Permissible Dose) for dental professionals per year?
5 rem or 50 mSv.