Radiography and Atom Structure

Vocabulary flashcards covering key terms from radiography history, atom structure, radiation types, imaging systems, and prime factors influencing X-ray quality and quantity.

X-rays

Discovered by Wilhelm Conrad Roentgen on November 8 1895; first image was his wife's hand.

Wilhelm Conrad Roentgen

Discovered X-rays in 1895 in Germany.

Alpha (α) radiation

Heavy particles with weak penetration, stopped by paper or skin.

Beta (β) radiation

Lighter particles with more penetration, stopped by aluminum.

Gamma (γ) / X-rays

Electromagnetic radiation with high penetration, stopped by lead or concrete.

Fluoroscopy

Invented by Thomas Edison in 1896, allows real-time imaging with a continuous X-ray beam.

Thomas Edison

Invented Fluoroscopy in 1896.

CR (Computed Radiography)

A type of filmless radiography that uses imaging plates.

DR (Digital Radiography)

A type of filmless radiography that uses flat-panel detectors, offering faster imaging without cassettes.

ALARA

As Low As Reasonably Achievable; a safety principle to minimize radiation exposure.

PACS

Picture Archiving and Communication System; stores, retrieves, and shares digital images.

Protons

Positively charged particles located inside the nucleus of an atom.

Neutrons

Particles with no charge located inside the nucleus of an atom.

Electrons

Negatively charged particles that orbit around the nucleus of an atom.

Atomic Number (Z)

The number of protons in an atom.

Mass Number (A)

The total number of protons plus neutrons in an atom.

Negative Ion (anion)

An atom that has gained extra electrons.

Positive Ion (cation)

An atom that has lost electrons.

Atom

The smallest unit of matter that retains an element's chemical properties.

Element

A substance made of only one type of atom.

Matter

Anything that has mass and takes up space.

Ionization

The process of adding or removing electrons from an atom.

Directly Proportional

A relationship where if one quantity increases, the other also increases (e.g., mAs increases, density increases).

Inversely Proportional

A relationship where if one quantity increases, the other decreases (e.g., kVp increases, contrast decreases).

Radiolucent

Materials with a low atomic number that allow X-rays to pass through, appearing black on an image (e.g., air, soft tissue).

Radiopaque

Materials with a high atomic number that absorb X-rays, appearing white on an image (e.g., bone, metal).

Quantum Mottle

A grainy appearance on an image resulting from too few photons (low mAs).

Prime Factors

The three main factors controlling the X-ray beam and image quality: mA, Time, and kVp.

Quality (of X-ray beam)

The penetrating power of the X-ray beam, controlled by kVp.

Quantity (of X-rays)

The number of X-rays produced, controlled by mAs (mA × time).

mA (milliamperage)

A prime factor that directly influences the quantity of X-rays produced.

kVp (kilovoltage peak)

A prime factor that controls the quality (penetrating power) of the X-ray beam.

Minimizing motion in radiography

Achieved through short exposure time, patient instructions (breath-hold), and immobilization if needed.

What are the 3 types of radiation

Alpha, gamma, and beta

Converting mA & Time → mAs

mA x s = mas

• Example: 200 mA × 0.1 s = 20 mAs

Converting mAs & Time → mA

mAs/s=mA

• Example: 40 mAs ÷ 0.2 s = 200 mA

Converting mAs & mA → Time

mAs/mA=s

• Example: 30 mAs ÷ 300 mA = 0.1 s

Converting Milliseconds to Seconds

1 second = 1000 milliseconds

Formula: ms/1000

Examples:

• 50 ms → 50 ÷ 1000 = 0.05 s

• 100 ms → 100 ÷ 1000 = 0.1 s

• 250 ms → 250 ÷ 1000 = 0.25 s

When did Roentgen win the Nobel Peace Prize

In 1901 and it was the first Nobel peace prize presented in physics

When did they start to realize the biological damage

1898

What are the xray characteristics

1. invisible

2. Electrically neutral

3. Have no mass

4. travel at the speed of light in a vacuum

5. •cannot be optically focused

6. form polyenergetic (heterogeneous beam)(photons have many different energies)

7. • Can be produced in a range of energies (medicaly useful xray energy range is 30 - 150 KVP

8. Travel in astraight lines

9. Can cause some substances to fuoresce

10. Can penetrate the human body

11. can be absorbed or scattered in the human body

12. can produce secondary radiation

13. can cause damage to living tissue

When was the first xray taken?

December 22, 1895 Of his wife’s hand