NBDHE Radiology Study Notes

Comprehensive vocabulary flashcards covering x-ray physics, radiation safety, radiographic quality factors, imaging types, and clinical pathology for the NBDHE.

Cathode (-)

The negative component of the x-ray machine containing a Tungsten filament that is heated to give off a cloud of electrons.

Anode (+)

The positive component of the x-ray machine centered around a focal spot made of tungsten.

Aluminum filter

A component that removes low-energy x-rays to reduce patient exposure.

Lead collimator

A device that narrows the x-ray beam to limit patient exposure and reduce scatter.

Density

The overall opacity or blackness of the radiographic image, determined by the amount of x-ray exposure and mainly affected by milliamperage (mA).

Contrast

The difference in radiographic densities between adjacent areas, influenced by the tube potential (kVp) or energy of the beam.

Inverse Square Law

States that the intensity of radiation decreases in proportion to the square of the distance from its source.

Short scale contrast

Produced by a lower kVp, resulting in more distinct black and white boxes with fewer shades of gray; helpful for detecting decay.

Long scale contrast

Produced by a higher kVp, resulting in many shades of gray; useful for evaluating bone density.

Maximum Permissible Dose (Occupational)

The limit for dental professionals or RDHs, which is $50\,milliSieverts$ ($mSv$) or $5\,rem$ per year.

Latent period

The time from exposure to radiation until the clinical signs of radiation injury appear.

Direct theory

The process where x-ray photons directly hit DNA or critical cell structures, causing immediate damage.

Indirect theory

The more common form of radiation damage where x-rays ionize water to form free radicals that subsequently damage DNA.

Xerostomia

Dry mouth resulting from damaged salivary glands, commonly seen in patients who have undergone head and neck radiation therapy.

Osteoradionecrosis

Bone death caused by radiation-induced hypovascularity.

Mitotic Activity

One of three characteristics determining radiosensitivity; cells that divide more frequently are more sensitive to radiation.

Periapical

A direct intraoral radiograph used to view the entire tooth and surrounding bone, ideal for root apices and anterior caries.

Bitewing

Direct radiographs available in vertical or horizontal forms; vertical versions are used for assessing the alveolar crest in bone loss patients.

Cone Beam Computed Tomography (CBCT)

An indirect extraoral imaging method that provides 3D images, making it ideal for implant assessment.

Cone Cut

An error resulting in a blank or clear area on the image because the sensor was not fully exposed to the x-ray beam due to misalignment.

Foreshortening

An error where teeth appear shorter than their true length due to an x-ray beam angle that is too steep.

Elongation

An error where teeth appear longer than they truly are due to an x-ray beam angle that is too shallow.

Ghost images

Blurred, distorted duplicate images appearing on the opposite side of a panoramic radiograph when a patient fails to remove external objects like earrings.

Mesiodens

A supernumerary tooth located between the upper central incisors, appearing as a small radiopaque structure.

Nasopalatine duct cyst

Also known as an incisive canal cyst; the most common non-odontogenic cyst, often appearing heart-shaped due to the anterior nasal spine.

Condensing osteitis

A localized bony reaction to low-grade, chronic pulpal inflammation, seen as a well-defined radiopaque area at the tooth apex.

Odontoma

A benign tumor made of tooth-like structures, appearing as radiopaque masses with irregular margins.

Fusion

An anomaly where two tooth buds fuse at the enamel, dentin, or cementum, resulting in one fewer tooth in the dental arch.

Gemination

An anomaly where a single tooth bud attempts to divide, resulting in a split (bifid) crown while the number of teeth remains the same.

Dens in Dente

A tooth anomaly where the enamel and dentin fold inward, creating a 'tooth within a tooth'; found commonly in maxillary lateral incisors.

Amalgam tattoo

A purplish lesion in the mucosa caused by embedded amalgam particles; appears as unidentified objects on a radiograph.