Radiology

The fundamental unit of matter which is the **smallest particle of an element** is:

**atom.**

A proton is a subatomic particle; the fundamental unit of matter is the atom. A neutron is a subatomic particle; the fundamental unit of matter is the atom. An electron is a subatomic particle; the fundamental unit of matter is the atom. The fundamental unit of matter is the atom.

Which subatomic particle carries a **negative electrical charge?**

**An electron**

A neutron does not carry an electrical charge. A proton carries a positive electrical charge. An electron carries a negative electrical charge. A nucleon carries a positive (proton) or no (neutron) electrical charge.

Which of the following statements is ***true*** of orbits or shells in the atom?

* The orbiting shell closest to the nucleus has the highest energy level. (binding energy)
* The energy level within each shell is the same
* Protons travel around the nucleus in well-defined shells
*  

An atom contains innumerable shells.

**The orbiting shell closest to the nucleus has the highest energy level. (binding energy)**

Electrons travel around the nucleus in well-defined shells. An atom contains a maximum of seven shells. Each of the maximum seven shells within an atom represents a different energy level. The orbiting shell closest to the nucleus has the highest energy level. The K shell is the orbiting shell closest to the nucleus.

The **nucleus** of an atom contains:

  **protons and neutrons.**

The x-ray was **discovered by:**

(Father of X-rays)

**Wilhelm Roentgen**

A **radiograph** is defined as:

**a picture on film produced by the passage of x-rays through an object or body.**

An x-ray is a beam of energy that has the power to penetrate substances and record image shadows on a receptor.  A radiograph is a picture on film produced by the passage of x-rays through an object or body. Radiography is the art and science of making dental images by the exposure of a receptor to x-rays.  Radiation is a form of energy carried by waves or streams of particles.

(1) ***Radiation*** is the emission and propagation of energy through space or a substance in the form of waves or particles. (2) ***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.

X-rays and visible light are a form of electromagnetic radiation. Which one is capable of causing **ionization** to occur?

 

 **x-rays** 

X-rays and visible light are forms of electromagnetic radiation. X-rays are capable of causing ionization. Visible light does not.

Which of the following forms of electromagnetic radiation has the **shortest wavelength** (highest frequency)?

Dental x-ray wave

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

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

The form of the x-ray beam that is **most detrimental to the** **patient** is:

compton scatter

Within the x-ray tube, **electrons** are generated by the:

 

tungsten filament in the cathode.

Heat is a byproduct of x-ray production. Which component of the x-ray tubehead **dissipates the heat** created by the production of x-rays?

Insulating oil

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

\n **X-rays with longer wavelength have less penetrating power.**

X-rays with longer wavelength have less penetrating power and x-rays with shorter wavelengths have more penetrating power. X-rays with longer wavelength are more likely to be absorbed by matter. Kilovoltage controls the wavelength and energy of the x-ray beam.

**Thermionic emission** of electrons occurs at the:

**tungsten filament in the cathode.**

Thermionic emission of electrons occurs at the tungsten filament in the cathode; the copper stem functions as a heat sink for the tungsten target; the molybdenum cup focuses the electrons into a narrow beam.

In the dental x-ray tube, the **number of electrons** created is controlled by:

milliamperage.

Which is the **most common** possibility when an x-ray photon interacts **with matter?**

Compton scatter

Which would you adjust if you wanted to create a **larger electron cloud?**

Milliamperage

The purpose of the **anode target** is to:

  convert electrons into x-ray photons.

Approximately what percentage of the kinetic energy (heat) of the electrons is converted to **x-ray photons** at the anode target?

1%

Interaction with the x-ray photon as a result of the photoelectric effect is harmful to the patient because **ionization occurs.**

The statement is true.

Which **property of x-rays** allows for the image on the receptor?

**Penetrating power**

\

(1) As kilovoltage (kVp), milliamperage (mA), and time (s) increase, x-ray beam intensity **decreases.** (2) As distance and filtration increase, the intensity of the x-ray beam **increases.**

Both statements are false.

You have been using a dental x-ray machine that has a 4-inch PID. Your new machine has an 8-inch PID. Given that all exposure factors remain the same, according to the **inverse square law**, the resultant beam would be ___________ as intense.

one quarter

When contrasted with the use of **70 kV** for dental x-rays, the use of **60 kV** would produce an image with the following:

\n increase in the contrast of the dental image. (black and white)

**Exposure time** is measured in:

\n impulses. (Impulses per second)

The **aluminum filters** are used to:

remove low energy, long wavelength x-rays. (Increases the penetrability of the beam)

In regard to **increasing density:**

an increase in either kV or mA will increase density. (mA is the controlling factor for density!)

Which of the following are a factor for the **x-ray beam intensity?**

distance

 

quality (kVp)

 

time (impulses/s)

 

quantity (mA)

The sole purpose of the **lead collimator** is to:

restricts the size of the x-ray beam.

(1) ***Density*** is the overall darkness or blackness of a dental image. (2) When the **mA is increased** while other exposure factors remain constant, the resultant image exhibits a **decreased** density and appears lighter.

The first statement is true; the second statement is false.

A **longer** position-indicating device (PID) results in:

an increased target-receptor distance and less magnification

What dental materials appear the most **radiopaque?**

metals

(1) **Overlapped interproximal contacts** are caused by improper vertical angulation. (2) To prevent **overlap,** the vertical angulation should be adjusted to +10 degrees.

Both statements are false.

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

black.

When a **high operating kilovoltage (kVp)** is used, (low/high) contrast and (many shades of gray/areas of black and white) are seen on the dental image.

Low contrast; many shades of gray

Which of the following imaging techniques would be considered an **extraoral image?**

panoramic exam

A dental image that has ______________ is said to have **high contrast.**

very dark areas and very light areas

(1) If you want to acquire more of the **maxillary bone** on a bitewing, you tilt the butt of the tubehead **upward.** (2) This is considered a more **positive** vertical angulation.

 

Both statements are true.

Which of the following is an **advantage** of digital imaging?

decreased patient exposure

The **bite-wing** image is used in the:

interproximal examination.

Your 35-year-old patient has **clinical attachment loss** in the posterior teeth and would therefore be deemed as a periodontal patient. What **type of bite-wing images** should you take, and what size receptor should you use?

Vertical; 2

In a **periapical image,** we should be able to visualize the following:

the crown and root of a tooth, and 2mm of the supporting bone

A **stepwedge** is composed of the following material:

\n aluminum

The IP contacts on your dental image are **closed.** You will need to take a retake. What should you do in order to achieve **open contacts** on your retake dental image?

Adjust the horizontal angulation to direct the PID through the contacts of the teeth.

***FMX*** stands for:

full mouth x-ray

**Horizontal bite-wings** should be used for patients exhibiting the following:

mixed dentition.

\
 

extensive decay.

 

health

 

all of the above

all the above

To minimize **dimensional distortion**, the object and receptor must be _____________ one another.

parallel to

The **geometric characteristic** of _____________ refers to an image that appears **larger** than the actual size of the object it represents.

magnification

Which of the following images is used to evaluate the maxillary **or** mandibular arch in **one intraoral image?** (often referred to as a "sandwich" bite technique)

Occlusal

If the **milliamperage (mA) is increased**, the receptor density ________, and the image appears _________.

increases; darker

Which size bite-wing receptor may be placed in a **horizontal or vertical position?**

Size 2

Where should you position the mesial edge of the receptor when taking a **premolar bite-wing image?**

Midline of the mandibular canine

Your patient asked you **why dental images are important.** Which of the following is the correct response?

Many dental diseases are discovered through the use of dental images.

You are showing your patient a **bite-wing image**. Your patient points to a portion of the tooth that is the **most radiopaque** and wants to know what it is. What portion of the tooth is your patient pointing to?

The enamel

William Crookes - Late 1870s

Discovered that cathode rays were streams of charged particles

his discovery lead to the TV Tube

Otto Walkhoff - 1896

Made the first dental radiograph

C. Edmund Kells - 1896

Introduced the paralleling technique

Exposed the first dental radiograph in the US using a living person

Howard Riley Raper - 1925

Refined original bisecting technique

Introduced the bite-wing technique

Weston Price - 1904

Bisecting technique

William Coolidge - 1913

Developed the first hot-cathode x-ray tube

Eastman Kodak - 1913

Prewrapped intraoral film

Hisatugu Numata - 1933

First to expose a panoramic radiograph

Yrjo Paatero

“Father of panoramic Radiography”

Experimented with slit beam radiography, intensifying screens, and rotational techniques

When was the intraoral imaging sensor (digital) introduced?

1987

Matter

anything that occupies space (composed of atoms)

Atom

fundamental unit of matter

has a central nucleus (Protons + and neutrons) and orbiting electrons-

Electrons travel around the nucleus in well-defined paths known as orbits or shells

==***The strongest binding energy is found closest to the nucleus (K Shell)***==

Binding energy is measured in electron volts or kilo electron volts (KeV)

Atoms can combine to form molecules

Ionization

An atom w/ an incompletely filled outer shell attempts to capture an electron from an adjacent atom.

==***An atom that gains or loses an E- and becomes electrically unbalanced is called an ion.***==

Radiation

Emission and propagation of energy through space as a substance in the form of waves or particles

Radioactivity

Process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, to attain a more balanced nuclear state.

What error is made when a bitewing image does not show open contacts between teeth?

Overlap

To avoid overlapped contacts on a periapical image a radiographer should adjust:

Horizontal angulation

A radiographer must have sufficient knowledge to perform efficient and accurate dental imaging along with:

Technical skills

When should a radiographer avoid retake images?

At all times (ALARA)

What happens when a radiographer increases kVp?

The electrons at the cathode filament are given the energy and speed to travel across to the anode target.

When the PID is not properly aligned with the image receptor (IR) this error can occur:

Cone cut

What is the purpose of the anode target?

Electrons are converted to x-ray photons

When acquiring a full mouth set of x-rays (FMX), what areas of the mouth should we expect to see:

All the edentulous and dentulous tooth-bearing areas of the maxillary and mandibular arches

What are the nonverbal communication cues that can make a patient feel secure in the radiographer:

* Eye contact
* Facial expressions
* Body movement

Name some advantages of digital imaging:

* Ability to view images quickly
* Easy to share with other healthcare providers when referring patients
* Patient Education
* No chemicals or darkroom needed

Give an example of each of the following:

* Direct-digital imaging
* Indirect digital imaging

Direct: Image receptor

Indirect: Film

In our clinic, how many images do we typically take for an FMX using #2 size sensor?

18

* 8 posterior PA’s
* 6 anterior PA’s
* 4 bite wings

When working with a patient that has a palatal tori, where should the radiographer position the IR for the patient comfort?

On the far side of the torus

How many shades of gray are used in digital imaging?

How many shades of gray can the human eye detect?

256

32

What is the term for infection control that means the absence of pathogens?

Asepsis

Critical instruments are defined as:

Instruments that are used to penetrate soft tissue or bone

(typically not used in radiography)

When obtaining anterior PA’s, what way is the ID oriented?

When taking posterior PA’S, in what way is the ID oriented?

* Vertically (anterior)
* horizontally (posterior)

When should a radiographer use a lead apron with a thyroid collar for the patient?

All intraoral exams

What happens to IR density when the mA is increased?

How will the image appear?

When mA is increased, density is increased as this is a direct relationship.

As density increases, the image will appear darker.

What does parallel mean?

Two lines or objects that are in the same plane and never intersect. These lines are always separated by the same distance.

If a patient has a shallow palate, you can modify your technique to compensate for the lack of parallelism by doing the following:

You can **increase your vertical angulation up to 20 degrees** to make up for the lack of vertical angulation caused by the patients anatomy.

When should bitewings or periapical images be taken on our patients?

As needed, based on the individual patients needs.

Inside the x-ray tube, electrons are generated by the:

Tungsten filament in the cathode

The appearance of a patient’s finger on the image is called a:

phalangioma

When would a radiographer need to take vertical bitewings?

How many vertical bitewings are typically taken on an adult with a full dentition?

vertical BMX are taken on periodontal patients as they show more of the IP alveolar bone levels

6 posterior vertical BMX’s are taken

What determines the binding energy of an orbiting electron?

Binding energy is determined by the distance between the orbiting electrons and the nucleus-binding energy is the greatest near the nucleus

What is true regarding x-rays with longer wavelengths:

Longer wavelengths have less energy and are less penetrable

In the dental x-ray machine, what is the purpose of the lead collimator?

restricts the size and shape of the beam

What is the purpose of the aluminum filters in the dental x-ray machine?

To filter out the long wavelength lazy x-rays and utilize the stronger more penetrable x-rays.

Where in the x-ray tube does the thermionic emission occur?

The tungsten filament in the cathode