RAD ch1 Radiation History

What is an x-ray?

A beam of energy that has the power to penetrate substances and record image shadows on receptors (photographic film or digital sensors).

What is a radiograph?

An image produced on a receptor by exposure to ionizing radiation; a two-dimensional representation of a three-dimensional object.

What is an image receptor?

A recording medium, such as x-ray film, a phosphor plate, or a digital sensor.

Define radiography.

The art and science of making radiographs by exposing a receptor to x-rays.

Define radiology.

The science or study of radiation as used in medicine.

Define dental radiography.

The production of radiographs of the teeth and adjacent structures by exposing an image receptor to x-rays.

Who is a dental radiographer?

Any person who positions, exposes, and processes dental x-ray image receptors.

Define dental imaging.

The creation of digital, print, or film representations of anatomic structures for the purpose of diagnosis.

What is x-radiation?

A high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube.

What is one of the most important uses of dental images?

Detection of disease.

What is an oral exam without dental images limited to?

What is seen clinically: the teeth and soft tissue.

Why are dental images needed to detect many diseases?

Many dental diseases and conditions produce no clinical signs or symptoms and are typically discovered only through imaging.

List the eight uses of dental images.

Detect lesions/diseases not seen clinically; confirm or classify suspected disease; localize lesions or foreign objects; provide information during procedures; evaluate growth and development; illustrate changes from caries, periodontal disease, and trauma; document a patient's condition at a point in time; aid in developing a treatment plan.

Who discovered x-rays and on what date?

Wilhelm Conrad Roentgen, on November 8, 1895.

What was Roentgen's profession and nationality?

A Bavarian physicist.

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

Cathode rays (streams of electrons), using a vacuum tube, an electrical current, and fluorescent screens.

What observation led Roentgen to discover x-rays?

A faint green glow from screens several feet from the tube, a distance greater than cathode rays could travel.

Why did Roentgen name his discovery "x-rays"?

The "x" represents the unknown nature and properties of the rays.

What was the first radiograph of the human body?

Roentgen's wife's hand, exposed for 15 minutes.

What honor did Roentgen receive for his discovery?

The first Nobel Prize ever awarded in physics.

What were the old terms for x-rays, radiology, and radiographs?

Roentgen rays, roentgenology, and roentgenographs.

Who built the first vacuum tube and when?

Heinrich Geissler, a German glassblower, in 1838.

Who named cathode rays and when?

Johann Wilhelm Hittorf, in 1870.

What did William Crookes discover about cathode rays?

That they are streams of charged particles.

What tube did Roentgen use?

The Hittorf-Crookes tube, which combined the best features of the Hittorf and Crookes designs.

What did Philip Lenard discover in 1894?

That cathode rays could penetrate a thin aluminum foil window in the tube and cause fluorescent screens to glow.

Who made the first dental radiograph?

Otto Walkhoff, a German dentist, in 1896.

Who made the first dental radiograph in the United States using a skull?

W. J. Morton, a New York physician.

Who exposed the first dental radiograph in the United States using a living person?

C. Edmund Kells, a New Orleans dentist.

What happened to Kells as a result of his work?

Repeated overexposure to x-rays caused cancers that cost him his fingers, then his hands, then his arms.

Who developed the first dental x-ray unit and wrote the first paper on the dangers of radiation?

William H. Rollins, a Boston dentist.

Who was the first to use film in intraoral radiography?

Frank Van Woert, a New York City dentist.

Who established the first college course in radiography for dental students?

Howard Riley Raper.

Who developed the hot-cathode x-ray tube and in what year?

William D. Coolidge, in 1913.

Why is Coolidge's tube important?

It became the prototype for all modern x-ray tubes.

What did the 1923 Victor X-Ray Corporation machine introduce?

A miniature x-ray tube placed inside the machine head and immersed in oil; the precursor of all modern dental x-ray machines.

When was the variable kilovoltage dental x-ray machine introduced?

1957

Who manufactured the first prewrapped intraoral films and when?

Eastman Kodak Company, in 1913.

When did the first machine-made periapical film packets become available?

1920

How did dental x-ray packets look from 1896 to 1913?

Glass plates or film cut into small pieces and hand-wrapped in black paper and rubber.

How much exposure time does fast film require compared with 1920?

Less than 2% of the initial exposure time used in 1920.

Why does faster film benefit the patient?

Shorter exposure time reduces the patient's exposure to radiation.

In what years were D-speed, E-speed, and F-speed film introduced?

D-speed in 1955, E-speed in 1981, and F-speed in 2000.

What are the three intraoral techniques used in dentistry?

The bisecting technique, the paralleling technique, and the bite-wing technique.

Who introduced the bisecting technique and when?

Weston Price, a Cleveland dentist, in 1904.

Who redefined the bisecting technique and introduced the bite-wing technique?

Howard Riley Raper, with the bite-wing technique introduced in 1925.

Who introduced the paralleling technique and when?

C. Edmund Kells, in 1896.

Who used the paralleling technique in practical dental radiography in 1920?

Franklin W. McCormack.

Who is the "father of modern dental radiography" and why?

F. Gordon Fitzgerald, who revived interest in paralleling with the long-cone paralleling technique in 1947.

What is the extraoral technique used most often in dentistry?

Panoramic radiography.

Who was the first to expose a panoramic radiograph?

Hisatugu Numata of Japan, in 1933 (film was placed lingually to the teeth).

Who is the "father of panoramic radiography"?

Yrjo Paatero of Finland.

When and where was the first intraoral digital imaging sensor introduced?

1987, in France.

When was direct digital imaging first described in U.S. dental literature?

1989

List the benefits of digital imaging.

Instant and easy transmission, electronic storage, reduced patient exposure, increased diagnostic potential, and reduced chemical waste.

What does cone-beam computed tomography (CBCT) allow?

Viewing of oral structures in three dimensions, without magnification, distortion, or superimposition.

When did CBCT scanners become available in the United States?

2001

What did the American Dental Association recognize in 1999?

Oral and Maxillofacial Radiology as its ninth dental specialty.

What training is required for Oral and Maxillofacial Radiology?

A 2- or 3-year residency after dental school, followed by an international board examination.