Chapter 1 Physics

Who discovered X-rays?

Dr. Wilhelm Conrad Roentgen

When was Roentgen born?

March 27, 1845

Where was Roentgen born?

Lennep Germany

Where did Roentgen earn his PhD?

University of Zurich (1869)

Where was Roentgen director of physics?

University of Wurzburg

When did Roentgen discover X-rays?

November 8, 1895

What was Roentgen experimenting with when he discovered X-rays?

A cathode ray tube and cardboard painted with barium platinocyanide

When was the first radiograph taken?

December 22, 1895

Early radiation use caused what?

Burns and electrocution

Who brought up the dangers of X-rays?

Thomas Edison

Who continued with X-rays despite Edison’s warnings?

Clarence Dally

By 1900, improved plates, equipment, and techniques nearly eliminated acute _______.

Radiodermatitis

What are the three fundamental quantities?

Mass, length, and time

What are the six derived quantities?

Velocity, acceleration, force, momentum, work, and power

What are the four special/radiologic quantities?

Dose, dose equivalent, exposure, and radioactivity

What is the British measure of mass?

Pound

What is the metric measure of mass?

Kilogram

What is the British measure of length?

Foot

What is the metric measure of length?

Meter

What is the British measure of time?

Second

What is the metric measure of time?

Second

What is inertia?

The property of an object with mass that resists a change in its momentum

What is energy?

The ability to do work

What is potential energy?

Energy in a stored state

What is kinetic energy?

Energy being expended

What are the four forms of energy?

Electromagnetic, electrical, chemical, and thermal

What is the British measure of exposure/intensity?

Roentgen (R)

What is the metric measure of exposure/intensity?

Coulomb/kilogram (C/Kg)

What does exposure/intensity measure?

Electrons liberated by ionization per kg of air

What is the British measure of absorbed dose?

Rad

What is the metric measure of absorbed dose?

Gray (Gy)

What does absorbed dose measure?

The quantity of radiation energy absorbed by tissues

What is the British measure of occupational exposure/dose equivalent?

Rem

What is the metric measure of occupational exposure/dose equivalent?

Sievert (Sv)

What does occupational exposure/dose equivalent measure?

The biologic effects of different types of ionizing radiation

What is the British measure of radioactivity?

Curie (Ci)

What is the metric measure of radioactivity?

Becquerel (Bq)

What does radioactivity measure?

The number of individual atoms decaying per second

What does KERMA stand for?

Kinetic Energy Released per unit MAss

What does KERMA describe?

The quantity of radiation energy delivered to a given point

What is a mobile unit?

A unit mounted on wheels

What is a permanently installed unit?

Units fixed in place is a room designed specifically for imaging

What is a tube head assembly composed of?

X-ray tube, collimator, and the tube stand

What do radiographic tables feature?

A four-way floating top with electromagnetic locks that can be raised or lowered

What does a wall unit consist of?

A vertical rail assembly and a vertical bucky assembly, allowing for easy upright examinations

What does the control panel do?

Allows for selection of kilovoltage (kVp) and milliamperage (mAs) that is applied to the x-ray tube

What does ALARA stand for?

As Low As Reasonably Achievable

What are the three principals of minimizing dose?

Shield, Time, and Distance

What are the four key protective actions?

1. Limit the size of x-ray exposure (collimation)

2. Control technical factors kVp and mAs

3. Screen female patients for potential pregnancy

4. Avoid unnecessary repeat examinations by “getting it right the first time”