The tube head limits the size of the primary beam by regulating the:
a. Size of the tube
b. Number of electrons
c. Length of the cylinder
d. Diameter of the collimator
e. Thickness of the filter
The collimator restricts the size of the beam.
Increasing the film-to-source distance results in:
a. Less distortion
b. More distortion
Film-to-source or source-to-film distance is determined by the length of the cone. The longer the cone, the less distortion.
The purpose of the lead diaphragm in the tube head is to:
a. Filter out low level x-ray
b. Diffuse the x-ray beam
c. Limit size of x-ray beam
d. Prevent scattered radiation
The collimator which restricts the size of the beam is made of lead in the shape of a diaphragm (disk with a hole in it).
Dental film speed is determined by the amount of exposure needed to:
a. Penetrate the lead foil in the film packet
b. Block the path of the central beam
c. Reduce contrast on the radiography
d. Produce a diagnostic radiograph
The spread of the film determines how much x-ray is needed to expose the film
When placing the dental film packet, the white side of the film:
a. Is placed facing the tooth
b. Is placed towards the tongue
c. Has no bearing on placement
d. Is placed away from x-rays
The white side is also called the tube side because it faces the source of x-rays
The speed film requiring the least amount of x-ray exposure is:
E speed fil requires about 1/2 the exposer as D speed.
Vertical angulation in radiographic projections regulates the:
a. Contrast of the image
b. Width of image
c. Definition of the image
d. Length of image
e. Overlapping of image
The less vertical angle, the longer the image more vertical angle results in a SHORTER image.
Horizontal angulation in radiographic projections regulates the:
a. Length of image
b. Contrast of the image
c. Overlapping of image
d. Definition of image
Incorrect horizontal angle results in overlapping.
The maximum permissible dose (MDP) for the operator is:
a. 4 R per year
b. 5 R per year
c. 6 R per year
d. 7 R per year
Maximum permissible is 5 R or 5 rems per year (.05 Sv)
3 R or 3 rems per Quarter (.03 Sv)
.1 rem per week (.001 Sv)
Public / Pregnant radiation workers are 1/10 of the above:
.005 / year
.003 / quarter
.0001 / week
The most radio-sensitive facial tissue is:
Lens of the eye to be specific.
X-radiation that has passed through an object is termed:
b. Primary radiation
c. Secondary radiation
Secondary or scatter radiation. It has a longer wavelength and has less penetrating power.
Activating the electronic timer causes the x-ray tube to:
a. Emit electrons
b. Deactivate the electron cloud
c. Emit secondary radiation
d. Emit primary radiation
Activating the timer causes x-ray production (primary beam)
The body tissue most sensitive to x-ray damage is:
The effect of x-radiation on human tissue is:
Cumulative - meaning damage is never completely healed. It continues with each x-ray exposure.
Adjusting milliamperage of the x-ray tube:
a. Quantity of x-rays
b. Quality of x-rays
c. Contrast of the radiograph
d. Wavelength of the x-rays
mA controls the amount of x-radiation
The type of x-rays best able to penetrate body tissues are:
a. Soft rays of long wavelength
b. Soft rays of short wavelength
c. Hard rays of long wavelength
d. Hard rays of short wavelength
Hard or penetrating x-rays are those of SHORT WAVELENGTH.
The negatively charged part of the x-ray tube is the:
d. Focal spot
Cathode contains the filament for the source of electrons and is negative.
To provide a single radiograph of the patient's complete dentition, the exposure of choice is the:
Panoramic radiograph gives the a view of the full dentition.
Which film size is considered for children only:
0 size film is so small, the only application that it has is children.
The optimal time for rinsing films between developing and fixing during manual processing is:
a. 10 min
b. 30 sec
c. 20 min
d. 10 sec
Developing is timed according to the temperature, fixing is always 10 minutes, by rinsing between the two is 30 seconds. The final wash is 20 minutes in running water.
The function of the x-ray fixing batch is to:
a. Stop the developing action
b. Darken exposed silver salts
c. Give contrast to the film
d. Remove traces of chemicals
Stopping development is one function. The other functions are to remove undeveloped silver halides and shrink/harden the emulsion.
The chief source of radiation exposure to the operator is:
a. Primary radiation
b. Scattered radiation
c. Hard radiation
d. Image forming radiation
Scattered or secondary radiation.
Light and x-radiation travel at what speed?
a. 86,000 miles per second
b. 186,000 miles per second
c. 1,186,000 miles per second
d. 2,186,000 miles per second
When a film holder device is not being used, what is the recommended position for the sagittal plane of the patient?
a. 135 degrees to the floor
b. Parallel to the floor
c. Perpendicular to the floor
d. 45 degrees to the floor
The sagittal plane divides the patient into right and left. To keep the patient's head upright, it must be perpendicular to the floor.