2026 RHS Exam Prep (DANB) – High Yield

Image receptor

records the x-ray image (sensor, PSP, or film)

Ionization

Process where atoms gain or lose electrons and become charged

Ions

Atoms with a positive or negative charge

Bremsstrahlung radiation

X-rays produced when electrons are slowed near the nucleus

Tubehead components

X-ray tube head , extension arm, and control panel

Insulating oil

Absorbs heat and prevents overheating in the tubehead

Aluminum filter

Removes low-energy, non-penetrating x-rays

Position Indicating Device (PID)

Lead-lined, open-ended cylinder that directs the x-ray beam

Short wavelength x-rays

High energy and greater penetration

Long wavelength x-rays

Low energy and less penetration

Photons

Packets of x-ray energy no weight or mass

Cathode

Negative electrode that produces electrons

Anode

Positive electrode that converts electrons into x-rays

Energy converted to heat

99% of electron energy becomes heat

Energy converted to x-rays

1% of electron energy becomes x-rays

Kilovoltage peak (kVp)

Controls beam quality and penetrating power

Milliamperage (mA)

Controls quantity of x-rays produced

Exposure time

Controls length of exposure and image density

Impulses

Units used to measure exposure time (60 impulses = 1 second)

Secondary radiation

Radiation produced when the primary beam interacts with matter

Primary radiation

Radiation emitted directly from the x-ray tube

X-ray interaction with atoms

Can disturb electrons and cause ionization

Electrons

small, negatively charged particles

X-radiation

High energy ionizing electromagnetic radiation

X-ray tube head

equipment consisting of the x-ray tube, collimator, and operator controls; permits manipulation of x-ray tube in many directions for proper positioning

X-Ray Extension Arm

wires located inside attached to tube head and control panel

X ray control panel

Master Switch ; indicator light ; selector buttons and exposure buttons

X-ray image

film based or digitally produced recording of anatomic structures

Position indicating device (PID)

Aims and shapes the x-ray beam; open ended, lead lined cylinder that extends from the opening of the metal housing of the tubehead. Sometimes referred to as the cone.

XCP

To position and hold an Xray

Scatter radiation

Radiation that is deflected from its original path after interacting with matter

Radiolucent

Structures that allow x-rays to pass through and appear dark on the image

Examples of radiolucent structures

Pulp, air spaces, soft tissue

Radiopaque

Structures that absorb x-rays and appear light or white on the image

Examples of radiopaque structures

Enamel, bone, metal restorations

Sharpness

The ability to see fine lines and detail in an image

Density

The overall darkness or blackness of a radiograph

Contrast

The difference in shades between black, gray, and white on a radiograph

What does high kVp produce

Low contrast (long scale contrast) with many shades of gray

What does low kVp produce

High contrast (short scale contrast) with fewer shades

What does increasing kVp do

Increases density and decreases contrast

What does decreasing kVp do

Decreases density and increases contrast

What does increasing mA do

Increases density by increasing number of x-ray photons

What does decreasing mA do

Decreases density

What does increasing exposure time do

Increases density

What does decreasing exposure time do

Decreases density

What is quantity in x-rays

The number of x-ray photons produced

What controls quantity of x-rays

mA and exposure time

What is amperage (mA)

A measurement of the number of electrons flowing

Penumbra

The blurred or fuzzy edge around an image

What causes magnification

Image receptor placed too far from the tooth or short PID

Latent period

Time between radiation exposure and appearance of effects

What is ionizing radiation

Radiation capable of removing electrons from atoms

Acute radiation dose

Large dose received in a short period of time

Chronic radiation dose

Small doses received over a long period of time

What is the tungsten target

Area of the anode where electrons strike to produce x-rays

Genetic cells

Reproductive cells (sperm and ova)

Genetic effects

Damage passed to future generations

Somatic cells

Body cells that are not reproductive

Somatic effects

Damage not passed to future generations

Maximum permissible dose (MPD)

5.0 rems (5000 millirems) per year for occupational exposure

What does a collimator do

Restricts size and shape of x-ray beam to reduce exposure

Types of collimation

Round or rectangular

What is a PID

Position indicating device that directs the x-ray beam

PID lengths

8, 12, or 16 inches

Which PID reduces radiation exposure

Long PID reduces exposure more than short PID

Why should lead aprons not be folded

Folding can cause cracks that reduce protection

What does the aluminum filter do

Removes low-energy, long wavelength x-rays

Required aluminum filtration

Minimum 2.5 mm aluminum for machines at 70 kVp or higher

What is a dosimeter

Device that measures occupational radiation exposure

Another name for dosimeter

Personal radiation monitoring badge

What does ALARA stand for

As Low As Reasonably Achievable

Maxillary sinus

Radiolucent space above posterior maxillary teeth

Floor of maxillary sinus

Radiopaque line outlining the maxillary sinus

Nasal cavity

Radiolucent area above maxillary incisors

Nasal septum

Radiopaque vertical line dividing the nasal cavity

Anterior nasal spine

Radiopaque V-shaped structure above maxillary central incisors

Incisive foramen

Radiolucent area between maxillary central incisors

Median palatine suture

Radiolucent line between maxillary central incisors

Zygomatic process

Radiopaque U- or J-shaped structure above maxillary molars

Mental foramen

Radiolucent round/oval area near mandibular premolars

Mandibular canal

Radiolucent band with radiopaque borders below mandibular molars

Mental ridge

Radiopaque line in anterior mandible

Mental fossa

Radiolucent area above the mental ridge

Genial tubercles

Radiopaque ring below mandibular incisors

Lingual foramen

Radiolucent dot inside genial tubercles

External oblique ridge

Radiopaque line above mandibular molars

Internal oblique ridge

Radiopaque line below external oblique ridge

Cancellous bone molar region identification

Maxillary tuberosity (posterior rounded area behind maxillary molars)

White shadow in center of panoramic image

Patient is slumped; correct by standing up straight / elongating spine

Radiolucent lines in mandibular anterior region

Nutrient canals

Radiolucent landmark in mandibular incisors

Lingual foramen

PID classification

Non-critical

Disinfectant for PID and contaminated surfaces

Intermediate-level disinfectant (EPA registered)

Gloves for cleaning operatory after radiographs

Utility gloves

Agency that protects workers from infection

OSHA

Radiograph to capture mandibular nerve near third molars

Panoramic radiograph

Digital imaging always requires

Computer monitor

Sensor holder classification

Semi-critical

First step when disinfecting sensor for first time

Read manufacturer instructions