History Flashcards
Who discovered X-rays and when?
Wilhelmina Conrad Roentgen
November 8, 1895
First X-ray exposure?
On wife Berthas hand. It was a 15min exposure
X-ray pictures aka
Radiographs
What does ASRT stand for?
American Society of Radiologic Technologists
When was the ASRT found
Chicago 1920
What is JRCERT?
Joint Review Committee on Education in Radiologic Technology
Formed in 1969
Conducts accreditation of RT schools
Computed Tomography CT
Computerized X-ray system that provides axial images (transverse slices) of the body
The source of X-rays
X-ray tube
X-rays that travel in a useful direction exit the housing through
An opening called the tube port
An imaginary line in the center of the X-ray beam and perpendicular to the long acid of the X-ray tube
Central Ray
A portion of energy of the X-ray beam is absorbed with matter. Absorption of the X-ray beam is called?
Attenuation
What causes unwanted exposure to the film and to anyone who is in the room
Scatter radiation
The unwanted image exposure by scatter radiation is called
Scatter radiation fog
The image receptor (IR) consists of?
X-ray film and film holder aka cassette
What is CR?
Computed radiography aka filmless systems
With CR how is the image obtained?
In a phosphor material on a plate inside a closed cassette
What is Primary Radiation
The X-ray beam that leaves the tube and is unattenuated, except by air
It’s direction and location are predictable and controllable
What is Remnant Radiation?
What remains of the primary beam after it has been attenuated by matter
The pattern of remnant radiation created the image
Definition of scatter radiation
Radiation that is scattered or created as a result of attenuation of the primary X-ray beam by matter.
Has less energy then the primary beam.
Film size for Fluoroscopic spots
24x24 cm
What is a detent?
A special mechanism that tends to stop a moving part in a specific location
What is a collimater
A boxlike device that is attached under the tube housing
What is a Bucky?
A grid device that protects the IR from scatter radiation and fog.
When are grids used
Body parts that are generally 10-12 cm or more in thickness
Pre-exposure safety check
1) X-ray room door is closed
2) No nonessential persons are in the X-ray room
3) All persons in the control booth are completely behind the lead barrier
4) No image receptors are in the room except the one in use
All matter is composed of building blocks called?
Atoms
Matter can be neither created nor destroyed but it can…
Change form
Energy can be neither created nor destroyed, but it can…
Change form
Proton-
Location, mass #, charge
Nucleus, 1, +1
Neutron-
Location, mass #, charge
Nucleus, 1, 0
Electron-
Location, charge
Orbital shells, -1
Two or more atoms may combine chemically to form
Molecules
A substance that consists of only one type of molecule is called
A chemical compound
Produces an atom with an electric charge
Ionization
Definition of energy
The ability to do work
What does electromagnetic energy consist of?
Light, X-rays, radio waves, microwaves, and other forms of energy
What is the frequency of the wave?
The # of times per second that a crest passes a given point
X-rays with greater energy have
Shorter wavelengths and are more penetrating
The smallest possible unit of electromagnetic energy is
A photon
Resistance depends on what 4 factors?
The material of the conductor, it’s length, it’s diameter, and it’s temperature
What kind of tube was used when Roentgen discovered X-rays
Crooks tube
What tube was the prototype for modern X-ray tubes?
Coolidge tube aka
Hot cathode tube
The NCRP recommended annual effective dose limit for occupational exposure
5.0 rem (0.05 Sv)
The NCRP recommended monthly effective dose limit to the fetus for a pregnant worker
O.05 rem (0.0005 Sv)
The conventional (British system) radiation unit to express radiation intensity in the air
Roentgen
The conventional (British System) unit commonly used to report occupational dose to radiation workers in the US is the
rem
What is the conventional (British System) radiation unit of absorbed dose
Rad
According to the Bergonie-Tribondeau law, the following types of cells are most radio sensitive
Embryonic tissue cells
Type of X-ray photon interaction with the body is primarily responsible for the radiation dose absorbed by the patient
Photoelectric
The NCRP recommendation for lead equivalency if aprons used for personnel protection
.5mm
Erythema as it related to radiation exposure
Reddening of the skin caused by a high radiation dose
The guiding philosophy of radiation protection
ALARA– as low as reasonably achievable
The following statements reflects current scientific opinion regarding the effects of duo gnostic levels of ionizing radiation
There is an increased risk of cancer, leukemia, birth defects, and cataracts
The following changes would decrease patient dose
Using a faster-speed class imaging system
Increasing the grid ratio to a 16:1 ratio
At what kVp levels do Compton interactions occur?
They occur throughout the duo diagnostic radiology kVp range
The principle source of scatter radiation in radiography
The IR
The 4 essential elements required for X-ray production
A target, a vacuum, an electron source, and a high potential difference
The greatest portion of the X-ray beam is made up of?
Bremsstrahlung radiation
The following functions involve the auto transformer
KVp selection
What is the IR that is used for CR?
Photostimuable phosphor (PSP) plate
The target of the X-ray tube is made of
Tungsten
How often should lead aprons and gloves be checked for cracks or holes
Every 6 months
The following will result in increased radio graphic density
Increased mA
Increased exposure time
Increased lVp
If the radiographic image is overexposed, which of the following changes in exposure factors should be used to correct the problem
Decrease the mAs
The relationship between the SID and beam intensity is expressed in the
Inverse square law
What are the 4 primary factors of radiographic quality
Density
Contrast
Distortion
Record detail
Contrast is primarily controlled by altering the
KVp
Motion of the patient, the tube, or the IR during the exposure will result in decreased
Recorded detail
A grid should be employed when the part thickness is greater than
12 cm
The following pathological conditions would require a decrease in exposure
Multiple myeloma
Emphysema
Osteoporosis
The screen or film image artifact looks like lightning
Static artifact
What is the name of the upper portion of the lung?
Apex
The inferior lateral corners of the lungs, visible on a PA chest radiograph, are called the
Costophrenic angles
Where does the CR enter the pt for the upright, PA projection of the chest?
Midsagittal plane at the T7
Lateral projections of the chest are taken with the left side against the IR because
Magnification of the cardiac silhouette is reduced with the left side neared the IR
How much should the CR be angled cephalad for an AP axial projection of the chest if the pt cannot assume the lordotic position?
15 degrees
Which chest projection and position are needed to demonstrate free pleural fluid along the dependent chest wall?
AP, lateral decubitus
Which of the following projections is best for demonstrating of the spices of the lungs without bony superimposition?
AP axial lordotic position
Why is a grid routine for a chest XR
To reduce scatter fog caused by use of high kVp
Which bones are tarsal bones?
Cuneiform and cuboid
When taking an AP axial projection of the foot, the CR is directed
10 degrees toward the heel
How much is the planter surface of the foot elevated from the IT for the AP oblique projection of the foot
30 degrees
Which foot projection/position will demonstrate the medial and intermediate cuneiforms without superimposition
AP oblique projection in 30 degree lateral rotation
Foot position will demonstrate the cuboid, navicular, and lateral cuneiforms without superimposition
AP oblique projection in 30 degree medial rotation
What bones articulate to form the ankle mortise
Talus, tibia, fibula
How many vertebrae are in the cervical region?
7
What anatomical structures of the cervical spine are best demonstrated by the lateral projection?
Zygapophyseal joints
How many vertebrae are in the thoracic spine?
12
What structures should be seen on a lateral projection of the T-spine?
T3-T12
How many vertebrae are in the lumbar spine?
5
Where does the CR enter for an AP projection of the L-spine?
At the level of the iliac creation the midline if the pt
What is the CR angel and direction for the AP axial projection of the sacrum?
15 degrees cephalad
What’s true regarding spine radiography to evaluate scoliosis
The IR should extend from the top of the patients ear to the level of the greater trochanter
What structure serves as the passageway for the spinal cord to exit the skull and pass into the spinal canal of the vertebral column
Foramen magnum
The Caldwell method of the skull (PA axial) of the skull the CR is directed
15 degrees caused
Which cranial projection best demonstrates the occipital bone?
AP axial (Towne Method)
Which of the following bones contain the paranasal sinuses?
Frontal ethmoid
Which of the following projections will demonstrate the sphenoid sinus?
Lateral
Which projection best demonstrates the maxillary sinuses?
Parietocanthial (waters method)
Which projection of the facial bones requires the central Ray to exit the acanthion
Parietoacabthial (waters method)
What change in technical factors is required when an ankle in a dry plaster cast must be radiographed?
Increase mAs by two times
How do you adjust mAs
Increase by 30% for every 2 cm
Calculate exposure time
mAs/mA= seconds
