Rad Physics Exam 1

Comprehensive vocabulary flashcards covering introductory radiographic science, historical developments, fundamental physical forces, units of measurement, energy types, and thermal physics.

Parsimony

The scientific principle stating that simple explanations are more likely to be true than elaborate ones.

Reproducibility

The requirement that scientific proofs or experiments can be duplicated by different people, at different times, and in different locations with precisely identical results.

Falsifiability

The requirement that scientific theories must be capable of being logically and logistically proven false.

Measurability

The rule that experimental results must be measured and mathematically quantified, including x-ray qualities like contrast, brightness, noise, sharpness, and distortion.

Wilhelm Conrad Roentgen

The German physicist who accidentally discovered X-rays on November 8, 1895, at Wurzburg University while experimenting with cathode rays in a Crookes tube.

Barium Platinocyanide

The fluorescent material coating the paper screen that unexpectedly glowed during Wilhelm Roentgen's cathode ray experiments.

Henri Becquerel

The French physicist who accidentally discovered natural radioactivity in 1896 when a stored uranium crystal fogged a wrapped photographic plate in a drawer.

Alpha Rays

Extremely heavy radioactive particles carrying positive electric charges, later proved by Ernest Rutherford to be identical to helium nuclei.

Beta Rays

Very light radioactive particles carrying negative electric charges, composed of high-speed electrons.

Gamma Rays

Very high-energy electromagnetic waves emitted during radioactive decay that travel short distances.

Ernest Rutherford

The scientist known as the Father of Nuclear Physics who proved alpha particles are helium nuclei, proved the existence of the proton, and predicted the neutron.

Albert Einstein

The physicist who won the Nobel Prize for discovering the photoelectric effect and developed the rest energy mass-equivalence equation $E = mc^2$.

Thomas Edison

The American inventor who developed the fluoroscope in 1896 and tested over $5,000$ chemicals to discover that calcium tungstate was the most efficient fluorescent light emitter.

Fluoroscopy

The radiological procedure of viewing internal body structures under radiation in real dynamic time.

Clarence Dally

Thomas Edison's assistant who suffered severe radiation injuries and became an early radiological fatality, leading Edison to cease his x-ray research.

John Coltman

The inventor who developed the electronic image intensifier in 1948, representing one of the greatest reductions in patient radiation dose in radiological history.

William Rollins

A dentist who introduced the foundational concepts of x-ray filtration and collimation in 1899.

William Coolidge

The inventor who introduced tungsten for x-ray filaments in 1913 and developed the hot-filament thermionic emission x-ray tube.

Thermionic Emission

The process in which electrons are boiled off from a heated cathode filament inside an x-ray tube.

Gustav Bucky

The researcher who introduced the first stationary grid in 1913 to reduce scatter radiation reaching the image receptor.

Hollis Potter

The inventor who connected an oscillating mechanism to Gustav Bucky's grid in 1921 to move the grid during exposure and eliminate grid lines.

Radiographic Grid

A device placed between the patient and image receptor containing alternating lead strips and interspace material to absorb scattered radiation.

Russell Morgan

The scientist who introduced phototimers for Automatic Exposure Control (AEC) in 1942.

Michael Pupin

The inventor who created the screen cassette in 1896 by sandwiching photographic film between two fluorescent screens.

Computed Radiography (CR)

A digital imaging technique introduced in the early 1980s that uses a photostimulable phosphor plate to store energy as a latent image before laser scanning.

Direct-Capture Digital Radiography (DR)

A cassetteless digital radiography system first demonstrated in 1996 that directly captures x-ray signals electronically without a separate reader.

PACS

Picture Archiving and Communication System; an electronic network introduced in 1982 that allows medical images to be archived and transmitted via teleradiology.

Post-Processing

The primary advantage of digital imaging, allowing brightness, contrast, and other features to be adjusted after exposure without repeating the original x-ray.

Ionizing Radiation

High-energy radiation capable of ejecting orbital electrons from atoms, creating charged ions and potentially harmful biological changes.

Radon Gas

A naturally occurring radioactive gas that accumulates in unventilated basements and accounts for approximately two-thirds of all natural background radiation exposure.

ALARA

An acronym for 'As Low As Reasonably Achievable,' the guiding rule of radiation protection designed to keep patient and occupational radiation doses to a minimum.

Time

A base quantity in physics measured in seconds ($s$) that dictates exposure duration, influencing x-ray beam quantity, patient dose, and motion blur.

Length

A base quantity in physics measuring distance, standardized in meters ($m$) in the SI system and commonly setting source-to-image distance (SID).

Mass

A base quantity in physics representing the quantity of matter in an object, measured in kilograms ($kg$), which remains constant regardless of location.

Weight

The force exerted by gravity on an object's mass, measured in pounds or newtons, which varies depending on gravitational acceleration.

Gravity

The fundamental attractive force between all matter, representing the weakest of the four universal forces.

Weak Nuclear Force

The fundamental nuclear force responsible for certain forms of radioactive decay operating within the atomic nucleus.

Electromagnetism

The fundamental force governing electrical charges, magnetic fields, and electromagnetic radiation, serving as the most important force in radiography.

Strong Nuclear Force

The strongest fundamental force in nature, operating over extremely short ranges inside the nucleus to bind protons and neutrons together.

Newton

The SI unit of force ($N$), defined as the force required to accelerate a $1\,\text{kg}$ mass by $1\,\text{m/s}^2$.

Derived Units

Units of measurement constructed from combinations of the three base physical quantities (time, length, and mass), such as speed ($\text{length}/\text{time}$) or density ($\text{mass}/\text{volume}$).

Density

A derived quantity defined as mass per unit volume ($D = \frac{m}{v}$), which determines how much radiation a material or tissue absorbs.

Angstrom

A unit of length equal to $10^{-10}\,\text{m}$ ($0.1\,\text{nm}$), used to express x-ray wavelengths which typically range from $0.1\,\text{\AA}$ to $0.5\,\text{\AA}$.

Joule

The standard SI unit of energy ($J$), defined as the capacity to do work or cause physical change.

Law of Conservation of Energy

The principle stating that energy cannot be created or destroyed in a closed system, only converted from one form to another.

Transducer

Any device that converts energy from one form into another, such as an x-ray tube, ultrasound probe, or electric light bulb.

Kinetic Energy

The mechanical energy an object or particle possesses due to its motion.

Potential Energy

The mechanical energy stored in an object or particle due to its position, state, or shape.

Gravitational Potential Energy

The potential energy stored in an object due to its elevation, calculated using the formula $\text{P.E.} = m \times g \times h$.

Photon

A discrete quantum or localized bundle of electromagnetic energy traveling at the speed of light.

Pascal's Law

The principle stating that pressure applied to an enclosed liquid is transmitted undiminished throughout the fluid because liquids are incompressible.

Conduction

The transfer of thermal energy between objects through direct physical contact and vibrating molecular collisions.

Convection

The transfer of thermal energy within liquids or gases through the physical circulation and mixing of warmer and cooler fluid regions.

Thermal Radiation

The transfer of heat energy through space via electromagnetic waves without requiring a material medium.

X-Ray Tube Energy Efficiency

The efficiency ratio during x-ray production where approximately $99\%$ of electron kinetic energy is converted into heat and only $1\%$ is converted into X-rays.

Speed

A measure of how fast an object is moving or traveling, representing the distance traveled compared to the time taken ($\text{speed} = \frac{\text{distance}}{\text{time}}$).

Velocity

A measure of how fast an object is traveling in a certain direction ($\text{velocity} = \frac{\text{distance}}{\text{time}}$ in a specific direction).

Law of Conservation of Energy

The principle stating that energy cannot be created or destroyed; it can only change forms or move from one object to another.

Potential Energy

The energy stored in an object due to its position or height above the ground.

Kinetic Energy

The energy an object possesses due to its motion, calculated using the formula $KE = \frac{1}{2}mv^2$.

Density

The mass of a substance per unit of volume, given by the formula $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

Formula for Time ($t$)

The mathematical equation used to find the time taken to travel a distance at a specified velocity, written as $t = \frac{d}{v}$.

Scientific Notation

A mathematical format for writing numbers using powers of 10, such as writing $14660000$ as $1.466 \times 10^7$.