Radiology Midterm Review: Key Concepts and Techniques

What are common X-ray errors that can occur?

Overexposed receptors, underexposed receptors, absence of apical structure, angulation problems, foreshortening, elongation, cone-cut, and phalangioma.

How can dental images assist clinicians?

They allow detection of conditions not visible clinically, such as diseases, caries lesions, and bone loss.

What should be done to avoid overlapped contacts on a periapical image?

Direct the X-ray beam through the interproximal region.

What happens when the kilovoltage is increased in X-ray imaging?

Electrons move from the cathode to the anode with more speed.

What is the primary advantage of digital imaging?

Superior gray-scale resolution, utilizing up to 32 shades of gray.

What causes a cone-cut in X-ray imaging?

Improper alignment of the PID with the periapical receptor holder.

What is direct digital imaging?

A sensor linked to a computer is placed in the patient's mouth and exposed to X-radiation.

What does CMS stand for in dental imaging?

A series of intraoral dental images that cover all dentulous or edentulous tooth-bearing areas of the upper and lower jaws.

Why is digital imaging preferred over film?

Images appear almost instantaneously for viewing.

What is the purpose of the anode in X-ray imaging?

To convert electrons into X-ray photons.

How many exposures are typically taken of the posterior teeth using the paralleling technique?

Eight exposures.

What technique is used for X-rays when a patient has a palatal torus?

Place the receptor on the far side of the torus.

What does asepsis refer to in dental radiography?

The absence of pathogens or disease-causing microorganisms.

What are receptor holders with aiming rings commonly used in dental radiography?

Rinn XCP.

How should anterior periapicals be positioned?

With the long portion of the receptor in a vertical direction.

What is the function of a lead apron in X-ray procedures?

To protect the patient during intraoral exposure.

What happens if the milliamperage is increased?

The receptor density increases, resulting in a darker image.

What does parallel mean in the context of X-ray imaging?

Moving or lying in the same plane, always separated by the same distance and not intersecting.

When are bite-wings and periapical images prescribed?

As needed based on the patient's individual needs.

What is used with sensors that cannot be sterilized?

Complete coverage with disposable plastic sleeves for each patient.

How does digital imaging produce an image?

Using an electric sensor and computerized imaging system.

What occurs at the tungsten filament in the cathode?

Thermionic emission of electrons.

What is the purpose of dental images in patient education?

To help educate patients about dental caries and periodontal disease, and to visualize conditions not seen clinically.

What is the basic rule of paralleling technique regarding the central ray?

The central ray should be directed perpendicular to the receptor and the long axis of the tooth.

How can the issue of distal surfaces of canines not being visible on a premolar bite-wing image be corrected?

Position the anterior edge of the receptor at the middle of the mandibular canine.

What does phalangioma refer to in dental imaging?

The appearance of a patient's finger in the image.

What are vertical bite-wings used for?

Often used with patients who have bone loss.

What does radiolucent mean in the context of dental X-rays?

Refers to the portion of the dental X-ray that appears black.

What is the most radiopaque portion of the tooth?

The enamel.

What do periapical X-rays evaluate?

The crown, roots, and supporting bone of a tooth.

What is required when using the intraoral paralleling technique?

A receptor holder.

Under what conditions should masks and safety glasses be worn?

Whenever spatter and aerosolized sprays of blood and saliva are likely.

What does milliamperage regulate in X-ray imaging?

The quality of electrons produced at the cathode filament.

What is vertical angulation in X-ray imaging?

When the PID is positioned above the occlusal plane and the central ray is directed downward, it is termed positive.

What causes a blurred image on a dental X-ray?

Patient movement during the exposure.

How can foreshortened mandibular incisors be corrected?

By decreasing vertical angulation.

What causes underexposed receptors?

Insufficient exposure time.

What is the definition of radiation and radioactivity?

Radiation is the emission and propagation of energy through space or a substance in the form of waves or particles; radioactivity is the process by which unstable atoms undergo spontaneous disintegration.

What is the result of a high contrast image in dental radiography?

Teeth appear very radiopaque while the periodontium and tissue appear very radiolucent.

What is necessary for digital X-rays compared to conventional radiography?

Digital images require 50% less exposure time and 90% less than conventional radiography.

What is a major placement error in a molar radiograph?

The receptor is placed too far distal.

What can a beam alignment device help with in dental radiography?

It helps the dental radiographer position the PID in relation to the tooth and the receptor.

What does the nucleus of an atom contain?

Protons and neutrons.

What are the basic principles of the paralleling technique?

The receptor is placed parallel to the long axis of the tooth, and the central X-ray beam is directed perpendicular to both the receptor and the tooth.

How can dimensional distortion be minimized in X-ray imaging?

By ensuring the object and the receptor are parallel to one another.

What does added filtration in the dental X-ray tube head result in?

A more penetrating useful beam.

What happens when the tungsten filament in the cathode is activated?

Thermionic emission of electrons occurs.

How can a dental image be corrected if apices do not appear?

Ensure the teeth being imaged are firmly in contact with the bite-block.

How can elongated maxillary premolars be corrected?

By increasing vertical angulation.

What are critical instruments in dental radiography?

Instruments used to penetrate soft tissue or bone.

What should be done when the exposure button is pressed?

It should be firmly depressed until the preset exposure time is completed.

What are the parts of the X-ray tube?

Includes the cathode, anode, glass envelope, and lead housing.