DHYG 113 Test 3

The fundamental unit of matter is the:

Atom

The nucleus of an atom contains:

Protons and neutrons

Which subatomic particle caries a negative electrical charge?

An electron

Which of the following statements is true of ionization?

An atom that gains an electron has a negative charge, and an atom that loses an electron has a positive charge

T/F: Radiation is the emission and propagation of energy through space or a substance in the form of waves or particles. Radioactivity can be defined as the process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state.

Both statements are true

Which of the following statements is true of wavelength in reference to radiation?

X-rays with longer wavelength have less penetrating power

_____ is a measurement of force that refers to the potential difference between two electrical charges

Voltage

When the kilo voltage is increased...

Electrons move from the cathode to the anode with more speed

The Kv represents...

The maximum or peak voltage of an alternating current

When lower kilo voltage settings are used, an image with ___ will result.

High contrast

Exposure time is measured in:

Hundredths of a second

The quantity of the x-rays produced is controlled by:

Milliamperage

According to the inverse square law, the intensity of radiation is ____ proportional to the ____ from the source of radiation.

Inversely; square of the distance

Radiolucent refers to that portion of a dental image that is:

Black

If the operating kilo voltage is increased, the receptor density ___ because the average energy of the x-rays is raised.

Increases

What physicist discovered x-rays?

Wilhelm Conrad Roentgen

What is the process of informing the patient about the particulars of exposing dental radiographs?

Disclosure

What is consent given by a patient following complete disclosure?

Informed consent

What law protects a patients information and generally prohibits the transfer of this information to non privileged persons?

Confidentiality

The gag reflex is elicited by stimulation of the sensitive tissues of the:

Soft palate

Which receptor placement is most likely to elicit the gag reflex?

Maxillary molar

A developmental disability is a substantial impairment of mental. or physical functioning that occurs before age years and is of indefinite duration

22

To help reduce the gag reflex:

Try to distract the patient by having them hold their feet up

What can be defined as the quality of care that is provided by dental practitioners in a similar locality under the same or similar conditions?

Standard of care

What refers the policies snd procedures that should be followed by the dental radiographer to reduce the chances that a patient will file legal action against the dental radiographer or supervising dentist?

Risk management

What results when the dental practitioner is negligent in the delivery of dental care?

Malpractice

Who is liable for the actions of a dental personnel?

The dentist and hygienist

Who legally owns the patients dental radiographs?

The dentist

The time during which a patient may bring a malpractice action against the dentist or auxiliary is termed:

Statute of limitations

Who was the German dentist responsible for creating the first dental radiograph?

Otto Walkhoff

What is matter?

Anything that occupies space and has mass

What are cathode rays?

Streams of high-speed electrons that originate in an X-ray tube

Particle radiation:

Tiny particles of matter that possess mass and travel in straight lines at high speeds

Electromagnetic radiation:

The propagation of wavelength energy without mass through space or matter

Metal housing:

Surrounds X-ray tube and transformers, protects tube, and grounds high voltage components

Insulating oil:

Surrounds X-ray tube and transformers, prevents overheating

Tubehead seal:

Permits exit of x-rays from tube head, seals the oil, filters x-ray beam

Transformer:

Alters voltage of incoming electricity

Aluminum disks:

Filter out non-penetrating, longer wavelength x-rays

Lead collimator:

Restricts size of x-ray beam

PID:

Aims and shapes the x-ray beam

Leaded glass housing:

Prevents x-rays from escaping in all directions

Cathode:

Negative electrode

Anode:

Positive electrode

T/F: The number of protons and neutrons in the nucleus of an atom determines its mass number or atomic weight

True

T/F: The number of protons inside the nucleus equals the number of electrons outside the nucleus and determines the atomic number

True

Where is the strongest binding energy found?

Closest to the nucleus in the K shell

An atom that gains or loses an electron and becomes electrically unbalanced is called:

An ion

The production of ions or the process of converting an atom into ions:

Ionization

The two groups of ionizing radiation are:

particulate radiation and electromagnetic radiation

What are the four types of particulate radiation?

1. Electrons

2. Alpha Particles

3. Protons

4. Neutrons

Only ___ radiations are capable of ionization

High energy

Bundles of energy with no mass or weight that travel as waves at the speed of light and move through space in a straight line:

Photons

The speed of the wave:

Velocity

The distance between the crest of one wave and the crest of the next:

Wavelength

The number of wavelengths that pass a certain point in a given length of time:

Frequency

Long wavelength =

Low frequency

Short wavelength =

High frequency

Weightless bundles of energy without an electrical charge that travel in waves

X-rays

T/F: X-ray photons interact with the materials they penetrate and cause ionization

True

____ consists of a tungsten wire filament that produces electrons when heated

Cathodes

Filament circuit:

Low voltage (3-8 V)

High voltage circuit:

65-100k V (accelerates electrons)

The quality or wavelength and energy of the x-ray beam is controlled by the:

Kilovolt peak (KVp)

A decrease in mA will cause:

A decrease in density

Results from the divergent paths of the x-ray beam as they radiate from the focal point:

Magnification

The capability of the x-ray receptor to reproduce the distinct outlines of an object:

Sharpness

Can demonstrate short-scale and long-scale contrast:

Aluminum step wedge

A certain lack of image sharpness which is present in every radiograph is called:

Penumbra

Influencing factors of density:

Milliamperage, operating kilovoltage, exposure time, subject thickness

What act outlines requirements for the safe use of dental x-ray equipment?

Consumer-patient radiation health and safety act

First to coin cathode rays:

Johann Hittorf

First skull radiation and full body radiograph (30 mins):

William J. Morton

First dental x-ray unit invented by:

William Rollins

Exposed first dental radiograph in the United Sates and also invented the paralleling technique:

Dr. Edmund Kells

Established the first college course in radiography for dental students, authored one of the first radiography textbooks and introduced bitewing technique:

Howard Riley Raper

Created the bisecting technique:

Weston Price

First to expose a panoramic radiograph:

Hisatugu Numata

Licensure requirements may include:

Exposing dental radiographs only under the direct supervision of the dentist (general supervision in Michigan).