Radiology

Question 1

What is the best way to produce a radiographic image with low contrast, hence longer gray scales?

Answer 1

Increasing the kilovoltage peak (kVp)

Question 2

What is measured by the half value layer?

Answer 2

Filtration

Question 3

What is the half-value layer?

Answer 3

The thickness of a material (usually aluminum) that decreases the intensity of the x-ray beam by 1/2

the higher the half-value layer, the thicker the piece of aluminum needed to block the x-ray beam

A quarter-value layer is the amount of a material that reduces the beam intensity to 1/4 of the value obtained without any test filters

Question 4

A dose of 4 grays of X-radiation administered locally to a patient’s hand would most likely result in ___

Answer 4

Erythema

The exposure to x-radiation beyond the allowable limit causes the top layer of the skin to experience tissue damage that is almost comparable with the damage of a sunburn

Question 5

Energy generated from carrying electrons from the cathode to the anode in a Crookes tube is converted into ___ at the target.

Answer 5

Heat

As the electrons travel in a rapid motion to hit the target, the heat is created an photons are also formed

Approximately 99% of these electrons are converted to heat as it hits the target.

Only <1% of the electrons that hit the target are converted to photons

Question 6

gamma rays are not part of the electromagnetic spectrum. they are used in the filed of medicine to…

Answer 6

Used in positron emission tomography (PET) scans and cancer therapy

Question 7

When making a radiograph, the number of electrons produced determines the ___

Answer 7

Quantity of the X-rays produced

Crookes tubes are able to create free electrons through the ionization of the air present within the tube with the use of a high voltage direct current. The high voltage current excites and accelerates the electrons that originated from the cathode. The excitation of the electrons causes them to move rapidly, hit the anode, and produce X-rays.

Question 8

The control over the X rays produced (quality) is based on the ____ and ___ of the X-ray machine

Answer 8

Peak kilovoltage (kVp)

Milliamperage (mA)

Question 9

Excessive exposure to X-radiation may cause ___ that may ___, ___, and ___.

Answer 9

The creation of free radicals

Damage DNA

Causing genetic mutations

And cancer growth

Question 10

True or false.. ionizing radiation directly affects DNA

Answer 10

False… it affects it through free radical formation

Question 11

What is affected by the change in peak kilovoltage (kVp)?

Answer 11

Quantity and quality of X-ray photons

Question 12

How does increasing kVp alter the quality of X-rays

Answer 12

Increases the intensity and energy thus degree of penetration

Question 13

What does an increase in milliamperage do?

Answer 13

Increases the quantity of x-ray photons produced. (Quantity only)

Question 14

What does increasing filtration do?

Answer 14

Increases quality while decreasing quantity

Question 15

The amount of penetration by x-ray beams is most likely associated with ____

Answer 15

Peak kilovoltage (kVp)

Question 16

How does Fixing solution interact with silver?

Answer 16

It removes underdeveloped silver salts

Question 17

What does fixing solution do?

Answer 17

Ensures that the image on the film is fixed permanently by removing the silver halide crystals which were unexposed or undeveloped and by preserving the emulsion.

Question 18

What does fixer solution contain? (5 things) what do they do?

Answer 18

Clearing agent - removes undeveloped silver halide crystals (ammonium thiosulfate)
Tanning agent - hardens and preserves the emulsion (aluminum salts)
Activator - maintains the fixer’s level of acidity and also neutralizes the developer (acetic acid)
Preservative - prolongs the shelf life of the solution (sodium sulfite)
Solvent - dissolves the other substance and ingredients (water)

Question 19

The mean energy (wavelength) of an x-ray beam is affected by what factors?

Answer 19

Filtration

Peak kilovoltage (kVp)

Voltage

Question 20

True or false… mA has NO affect on the mean energy of the beam

Answer 20

True

Question 21

What type of radiation poses the greatest danger to clinicians during radiography procedures?

Answer 21

Secondary radiation and scatter

Question 22

___ cells are most likely to be damaged first by radiation

Answer 22

Hematopoietic

Because they are actively dividing and undergoing several cellular processes to form many different cell types like red and white blood cells.

Question 23

Overexposure to radiation may result in what 3 negative outcomes?

Answer 23

Xerostomia

Mucositis

Osteoreadionecrosis

Question 24

True or false… X-rays are considered low energy waves

Answer 24

False.. they are high energy waves (higher than visible light)

Question 25

Alpha particles, beta particles, and neutrons are considered ___ radiation.

Answer 25

Particulate

Question 26

What material is responsible for making gutta-percha radiopaque?

Answer 26

Barium salts

Question 27

What type of radiograph provides the best visualization of the maxillary sinus for detection of pathology? Why?

Answer 27

Water’s (occipitomental view) - because it provides a larger image, better angle, and exposure of both the frontal and maxillary sinus

Panos provide a wide view of teeth and other structures of the head but CANNOT be used to completely evaluate the location and position of lesions within the maxillary sinus because of the image overlap

Question 28

Towne’s view is best in evaluating the…

Answer 28

Condyles, mastoid air cells, orbital floor, and the structures of the middle ear

Question 29

A reduction in the size of the focal spot of the X-ray tube leads to an increase in ___

Answer 29

Definition

Question 30

The definition and detail of the radiographic image are influenced by the focal spot through what three things?

Answer 30

The smaller the size of the focal spot, the better the detail, definition, or sharpness of the radiographic image created

The larger the size of the focal spot, the wider the coverage of the dam and more penumbra is created in the radiograph. This results in an unclear demarcation of the image outline and an increase in the blurriness of the image

The proper angulation of the beam and the size of the cone of an x-ray machine affects the size of the focal spot.

Question 31

The mucosa of the soft palate is innervated by what three nerves?

Answer 31

Lesser palatine nerve

Pharyngeal branch of vagus nerve

Medial pterygoid nerve

Question 32

True or false… the PSA nerve innervates the maxillary sinus mucosa

Answer 32

True

Question 33

The classification of third-molar impaction is based on what two things?

Answer 33

Spatial positioning relative to the long axis of the adjacent second molar

Amount of tooth structure covered by bone or soft tissue

Question 34

____ classification of tooth impaction is based on the position of the long axis of the third molar in relation to the long axis of the second molar

Answer 34

Winter’s

Question 35

____ classification of tooth impaction deals with the position of the lower third molar impaction within the ramus in relation to the second molar

Answer 35

Pell and Gregory’s

Question 36

What is indicated for a patient presenting with a persistent fascial plane infection following incision and drainage with adjunctive antibiotic therapy?

Answer 36

Repeat the culture and sensitivity assays

Question 37

Elliptical incisions should be made ___ to the dermatological skin tension lines to reduce scar visibility after wound healing

Answer 37

Parallel

Question 38

Which of the following interactions is responsible for the creating of Bremsstrahlung/Braking radiation?

Answer 38

Bremsstrahlung radiation is created when high-speed electrons interact with the Tungsten nuclei at the target.

The fast-moving electron loses kinetic energy when it interacts with the nuclei, converting the lost kinetic energy into a photon.

Question 39

A dentist’s radiograph of a patient’s 3rd molar at 0° vertical angulation looks like the superior border of the mandibular canal contacts the apices of the tooth. The dentist then makes another radiograph at a -2° vertical angulation that suggests that the mandibular canal is separated from the apices of the 3rd molar by several millimeters. Using the information provided by these two radiographs, which of the following is true about the relation of the mandibular canal to the root apices of the 3rd molar? The mandibular canal is…

Answer 39

Inferior and lingual