Quiz 1

Question 1

Definition of: X-ray

Answer 1

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

Question 2

Definition of: Radiation

Answer 2

A form of energy carried by waves or a stream of particles

Question 3

Definition of: Radiograph

Answer 3

An image or picture produced on a receptor (radiation-sensitive film, phosphor plate or digital sensor) exposure to ionizing radiation; a two-dimensional representation of a three-dimensional object

Question 4

Definition of: Dental radiographer

Answer 4

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

Question 5

Definition of: image

Answer 5

A picture or likeness of an object

Question 6

Definition of: image receptor

Answer 6

A recording medium; examples include x-ray film, phosphor plate or digital sensor

Question 7

Uses of dental radiographs

Answer 7

To detect lesions diseases and conditions of the teeth and surrounding structures that cannot be identified clinically. To confirm or classify suspected disease. To localized lesions or foreign objects. To provide information during dental procedures. to evaluate growth and development to illustrate changes secondary to caries, periodontal disease, and trauma. to document the condition of a patient at a specific point in time to aid in development of a clinical treatment plan.

Question 8

Roentgen

Answer 8

Discovered x-ray in 1895.

Question 9

Otto Walkhoff

Answer 9

Made the first dental radiograph.

Question 10

C. Edmund Kells

Answer 10

First practical use of radiograph in 1896. Exposed his hands to numerous x-rays every day for years.

Question 11

Atomic Structure

Answer 11

Normally most atoms are neutral. A neutral atom contains an equal number of protons (+ charges) and electrons (- charges)

Question 12

Definition of: Ion

Answer 12

An atom that gains or loses an electron and becomes electrically unbalanced is known as an ion.

Question 13

Definition of: Ionization

Answer 13

Ionization is a production of ions or the process of converting an atom into ions. Ionization deals only with electrons and requires sufficient energy to overcome the electrostatic force that binds the electron to the nucleus.

Question 14

Definition of: Ion pair

Answer 14

When an electron is removed from an atom in the ionization process. The atom becomes a positive ion, and the ejected electron becomes a negative ion. This ion pair reacts with other ions until electrically stable, neutral atoms are formed.

Question 15

Definition of: Ionizing radiation

Answer 15

Radiation that is capable of producing ions by removing or adding an electron to an atom.

Question 16

Properties of X-Rays

Answer 16

• Invisible.
• No mass or weight.
• No charge
• Travels at speed of light
• Short wavelengths with high frequency
• Travels in straight lines, can be deflected, or scattered.
• Cannot be focused to a point, always diverge.
• Penetrates liquids, solids, and gases.
• Absorbed by matter; depends on the atomic structure of matter and the wavelength of the x-ray.
• Interacts with materials they penetrate and cause ionization.
• X-rays can cause certain substances to fluoresce or emit radiation in longer wavelengths (e.g. visible light and ultraviolet light)

Question 17

What is the purpose of the copper stem?

Answer 17

The purpose is to conduct the heat out of the x-ray tube.

Question 18

Definition of: Transformers

Answer 18

A transformer is a device that is used to either increase or decrease voltage in an electric current.

Question 19

Definition of: Primary radiation

Answer 19

Refers to the penetrating x-ray beam that is produced at the target of the anode and that exits the tubehead.

Question 20

Definition of: Secondary radiation

Answer 20

Refers to x-radiation that is created when the primary beam interacts with matter. It is less penetrating than primary radiation.

Question 21

Definition of: Scatter radiation

Answer 21

A form of secondary radiation and is the result of an x-ray that has been deflected from its path by the interaction with matter. It is deflected in all directions by the patient’s tissues and travels to all parts of the patient’s body into all areas of the operatory.

Question 22

X-Ray Interactions

Answer 22

• X-rays can pass through the patient without any interaction.
• X-ray photons can be completely absorbed by the patient.
• X-ray photons can be scattered.

Question 23

All ionizing radiation is. . .

Answer 23

Harmful and produces biologic changes in living tissue.

Question 24

Radiation injury results from. . .

Answer 24

Ionization or free radical formation.

Question 25

Radiation injury follows a sequence of events:

Answer 25

Latent period, period of injury, and period of recovery.

Question 26

Radiation injury is affected by. . .

Answer 26

Total dose, dose rate,,amount of tissue irradiated, cell sensitivity, and patient’s age.

Question 27

Direct mechanism for radiation injury

Answer 27

X-ray photons directly strike the DNA of a cell

Question 28

Indirect mechanism a radiation injury

Answer 28

X-ray photons are absorbed within the cell and cost of formation of toxins, which in turn damage the cell.

Question 29

What is a dose-response curve?

Answer 29

A dose-response curve is used to demonstrate the response (damage) of tissues to the dose (amount) of radiation received. A threshold dose for damage does not exist, and the response of tissues is directly proportional to the dose received.

Question 30

Short- and long-term effects:

Answer 30

All the cells in the body can be classified as either somatic or genetic. Somatic cells are all the cells in the body except the reproductive cells. The reproductive cells are termed genetic cells.

Question 31

Total dose:

Answer 31

Quantity of radiation received or the total amount of radiation energy absorbed.

Question 32

Dose rate:

Answer 32

Rate at which exposure to radiation occurs and absorption takes place (**dose rate = dose/time**)

Question 33

Amount of tissue irradiated:

Answer 33

Areas of the body exposed to radiation.

Question 34

Cell sensitivity:

Answer 34

More damage occurs in cells that are most sensitive to radiation such as rapidly dividing cells and young cells.

Question 35

______ are more susceptible to radiation damage than ______

Answer 35

Children; adults

Question 36

Unit of: Exposure

Answer 36

SI unit - **C/kg** Traditional unit - Roentgen

Question 37

Unit of: Dose

Answer 37

SI unit: Gray (Gy) or **J/Kg** Traditional unit - Rad

Question 38

Unit of: Dose equivalent

Answer 38

SI unit: **Sievert (Sv)** Traditional unit - Rem

Question 39

Which critical organs are most at risk from dental imaging?

Answer 39

Thyroid gland, active bone marrow, skin, and eyes.