Radiology Physics and X-ray Production Flashcards

Vocabulary flashcards covering atomic structure, electromagnetic energy, x-ray production, transformer types, radiation terminology, and units of measurement based on lecture transcript notes.

Matter

Exists in forms of solid, liquid, and gas.

Atoms

Consist of protons and neutrons which make up the nucleus, and electrons which occupy orbits.

Tungsten

A material used in radiology because it has a high heating point.

Ionized

An atom that has a greater or less number of electrons than protons; important in radiology because x-rays cause ionization in body tissues.

Photons

X-ray photons that make up the beam, including bremstung and characteristic types.

K-shell

The innermost shell where the removal of an electron is a method of x-ray creation, requiring energy of $69.5\,kv$.

Electromagnetic Energy

Energy characterized by high frequency and short waves for x-rays, while radio waves have the longest wavelength and lowest energy.

Amplitude

The height or distance between the wave crest and trough in a sine wave.

Wavelength

The distance from crest to crest of a wave.

Frequency

The number of times per second a wave hits the crest.

Velocity

The speed of travel; an increase in speed equals an increase in energy.

kVp

Determines quality, energy, and penetration; controls contrast (black/white) and patient dose.

mAs

Determines quantity and the number of photons; controls density (brightness).

Scatter fog

A phenomenon that reduces contrast in an image.

Quantum mottle

A grainy appearance in an image caused by not having enough photons hitting the plate; results in increased contrast with decreased $kVp$.

Potential difference

The power or speed of electron flow, measured in Volts ($v$).

Electrical resistance

Anything that hinders the flow of current.

Direct Current (D-C)

Current that flows at a constant rate in one direction from anode to cathode.

Alternating Current (A-C)

Current flow that changes or alternates directions at $60\,\text{cycles per second}$ or $60\,Hz$.

Step Up Transformer

An electromagnetic induction device used to increase voltage and decrease amperage.

Step Down Transformer

An electromagnetic induction device used to decrease voltage and increase amperage.

Autotransformer

A variable $kvp$ selector used in the primary low voltage circuit.

Rectification

The process of changing Alternating Current (AC) to Direct Current (DC).

Thermionic emission

The boiling off of electrons from the filament.

Target

The actual focal spot where electrons strike; requires high potential difference ($kvp$ voltage).

Wilhelm Roentgen

Discovered x-rays on November 8, 1895.

Roentgen

The conventional unit used to measure radiation intensity in the air.

Air Kerma

The SI unit for radiation measure, expressed as $ker/columby$ or $kg$.

Rad

The conventional unit for absorbed dose.

Gray (Gy)

The SI unit for absorbed dose; $1\,rad = 0.01\,Gy$.

Rem

The conventional unit for dose equivalent.

Sievert (mSv)

The SI unit used for occupational and effective dose; $1\,rem = 0.01\,Sv$.

ESE (Entrance Skin Exposure)

The patient dose in radiography, always measured at the skin level.

Lethal Dose

A radiation dose of $4000\,msv$ or $4\,sv$ ($5000\,msv = 5\,gy$).

Line focus principle

The relationship between actual and effective focal spots where the anode angle makes the effective focal spot smaller than the actual focal spot.

Anode heel effect

The absorption of x-rays by the anode target heel, resulting in x-ray intensity being greater at the cathode than the anode.

Filtration

The primary purpose is to reduce patient dose by removing low-energy, long-wavelength x-rays using materials like aluminum, glass, or oil.