Radiology The study of electromagnetic radiation the movement

Radiology The study of electromagnetic radiation, the movement of photons, and their ability to create an image.

Why do we care about Radiology? Benefits? Disadvantages?

Chapters 1 & 2: The Technical Side of Imaging Basic concepts that impact x-ray settings: Fractions, +, -, x Proportionality Units of measurement Metric prefixes 3

Math Matters! Fractions “Pieces of the pie” Numerator/Denominator Used in technique charts m. A X seconds (fraction) Multiplication Used for exposure times m. A X seconds = m. As 4

Proportionality Definition: The relationship between two numbers Two types: direct & indirect Direct 1 st number is a multiple of the 2 nd Shown as fraction or with a colon Radiology example? Medical example? 5

Proportionality Indirect 1 st number up = 2 nd number down Product stays the same, but values differ Radiology example Inverse square law Medical example? 6

Length and Time Meter is standard unit Thickness of the patient Distance of x-ray tube to the patient’s body Second is standard unit Exposure time Processing time Understand metric prefixes Needed for conversions

The Atom & Radioactivity Atomic Theory Atomic Structure Combining Atoms Periodic Table t igh Atomic We Organizing Matter 8

History of Atomic Theory Ancient Greeks: 4 substances 4 essences Atom = “no division” Russian guy Periodic table Niels Bohr Atomic theory 9

Atomic Structure Maximum electrons = 2 n 2 Electrons (n = shell number) At least one per atom Held in place by their negative charge VERY small Orbit in rings called shells Limited # in each shell Can be added or subtracted Outer shells may be unstable Electron binding energy 10

Atomic Structure Protons: Positively charged Found in nucleus Balances (+) with (-) Determines atomic number (Z) Important in radioactivity Neutrons: Neutral charge Determines atomic mass (A) 11

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Organization of Matter Atoms elements molecules tissues Isotopes: Same atomic number but different mass Can be stable or unstable Important in imaging – contrast studies and nuclear medicine Radioactivity: Atom lives in an abnormal state of excitement …but all matter seeks stability Particles and energy are released & form new atoms 13

Organization of Matter Ionization: Lower electron binding energy leads to electrons leaving their shell imbalance in electrical charge = Atom is now ionized Radiology importance? 14