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BMO Review- Core

the formAnswer
The radiation that leaves the tube is called Primary Radiation
Absorption of the x-ray beam is called Attenuation
The primary source of scatter is The patient
Scatter radiation has more or less radiation than the primary x-ray beam Less
Unwanted image exposure caused by scatter radiation is called Fog
When a neutral atom gains or loses an electron this is called Ionization
The smallest possible unit of electromagnetic energy Photon
The measure of voltage across an x-ray tube is Kilovolt Peak (kVp)
The measure of x-ray tube current is Milliampere (mA)
When a conductor is placed in a magnetic field and there is movement between the lines of magnetic force and the conductor, current will flow in the conductor. This is called Electromagnetic Induction
The source of electrons in the s-ray tube is the Filament
The 4 essential requirements for the production of x-rays Vacuum, Source of electrons, Target, High potential difference
Electrons in the outermost orbital shells move so far from the nucleus that they are no longer held in orbit but are "flung" out of the atom, forming an electron cloud around the filament. This process is called Thermionic Emissions
Below 70 kVp, 100% of the photons in the x-ray beam are from which interaction? Bremsstrahlung
Above 70 kVp 15% of the x-ray beam is made of Characteristic radiation
The filament sits inside a focusing cup. What is the charge of the focusing cup? Slightly negative
What type of radiation is produced in the anode by the sudden slowing and directional change of an incoming electron? Bremstrahlung
What type of radiation is produced when an incoming electron interacts with a K-shell electron in the tungsten atom? Characteristic
What is found on a dual focus x-ray tube? 2 filaments and 2 focal spots
When taking into consideration the anode heel effect when radiographing a femur, how should the patient be placed on the table? with the head at the cathode side of the tube
Body parts in which you should take the anode heel effect into consideration? Femur, T-Spine, L-Spine
Considering the anode heel effect, the radiation intensity is stronger at the ___________ Cathode
The penetrating power of the x-ray beam is controlled by kVp
The auto-transformer is primarily used for Variable kVp selection
Contrast is controlled by which variable? kVp
Density is controlled by which variable? mA
the measure of the rate of current flow across the tube is mA
which variable controls the volume, or quantity of x-ray exposure, or the rate of exposure? mA
To determine the total quantity of radiation involved in an exposure, what 2 variables must be considered? mA and time
The unit used to indicate the quantity of an exposure is mAs
The length of time that the x-ray are "turned on" is called the Exposure time
what is the primary purpose of x-ray beam filtration? reduce the patient dose
the process of removing long-wavelength photons in the x-ray beam is called filtration
x-ray equipment capable of producing 70 kVp or more is required to have a total filtration of at least 2.5 mm Al equivalent
Inherent filtration in the x-ray tube is 0.5 mm Al equiv
Added filtration in the xray tube is 1.0 mm Al equiv
How much filtration does the mirror provide in the xray tube 1.0 mm Al equiv
the primary purpose of the filament circiut is to supply a low current to heat the x-ray tube filament for thermionic emission of electrons
the primary purpose of the high voltage circuit is to supply the x-ray tube with voltage high enough to create xrays
General range for kVp control on most machines is 45-125 kVp
general range for mA control on most machines is 25-500
when do we use the bucky grid system when the body part is more than 10 cm in thickness
what is the purpose of the bucky? reduce scatter
terminating the exposure when a certain amount of radiation has been detected at the film is called AEC; automatic exposure control
how to calculate heat units kVp x mA x s
the overall blackness on a film is called density
the difference between adjacent portion of an image is called contrast
geometric property that refers to differences between the actual subject and it's radiographic image is called distortion
the "unsharp edges" are called penumbra
the principal means of controlling involuntary motion is short exposure time
the principal means of controlling voluntary motion is clear communication with the patient
A CR cassette contain what type of plate inside? photostimulable phosphor or PSP
DR systems are considered "cassetteless" because they do not use an Ip inside, instead there is a detector unit built into the table or upright wall unit
indirect conversion is a 2 step process, what are the steps x-ray energy is converted to light and then to electric signal
direct conversion is a 1 step process, what is the step direct conversion to electrical signal
a seris of thousands of very small boxes or squares on the monitor is called the matrix
the individual matriz squares are called pixels
the amount of detail or sharpness as seen on the monitor is called spatial resolution
the ability o the digital system to convert the xray input electrical signal to useful radiographic image is called SNR: signal-to -noise-ratio
window leveling an image on the monitor controls density; this is also called brightness
noise refers to the amount of information that is not useful in the radiographic image. this noise is referred to as quantum mottle
a processing technique in which images cam be made sharper and have greatly increased contrast is called edge enhancement
ALARA as low as reasonably achieveable
DICOM digital imaging and communications in medicine
Health Level-7 is a communication standard for all hospital or clinics information systems.
Any unwanted item on an image is called an artifact; example necklace on CXR, ring on hand Xray, zipper on pelvis xray
PACS picture archival and communication system
2 xrays taken on the same film is called; as in forgetting to change the film double-exposure
the collimation field should be placed so that all 4 margins are seen on the film, or at least 2 sides of collimation should appear on the image
the principle method of reducing scatter is the use of a grid
the production of scatter radiation during an exposure results in fog
regarding grids, the number of strips per inch is called grid frequency
decreased radiographic density on one side of the image is called grid cut-off
grid cutoff is prevented by ensuring that the xray beam is always properly aligned with the center of the grid and at the appropriate distance
the standard control limit for the collimator is that the xray light field and the radiation field must be within +/- 2% of the SID
when imaging an obese patient, the single most imporaant adjustment that should be made is an increase in the kVp
when an image is too light, the best solution is usually to increase the mAs. the minimum change necessary to cause a visible change in am image density is 30% of the mAs
the 15% rules is based on the fact that a 15% change in kVp will produce approximately the same change iin radiographic density as doing what tot he mAs? double or half
to increase contrast, using the 15% rule what do we do to the kVp and and the mAs decrease kVp by 15% and double the mAs
to decrease contrast, using the 15% rule what do we do to the kVp and and the mAs in crease the kVp by 15% and take half ot he mAs
Unit of Absorbed Dose Air Kerma or Roentgen
Unit to measure exposure Gray or Rad
the amount of energy absorbed by the irradiated tissue is the Absorbed dose
the term used to describe the absorbed dose in the body based on the type of energy of radiation that the person was exposed to equivalent dose
short term effects are those observed within 3 months
long-term effects; also known as "latent effects" are observed several years after exposure, up to 30 years
somatic effects are those that affect the body and tissues of the person irradiated
genetic effects occur as a result of damage to the reproductive cells of the irradiated person and are observed as defects in their children and grandchildren
erythema reddening of the skin
cataractogenesis the formation of cataracts
carcinogenesis increased risk of malignant disease particularly cancer
RBE relative biologic effectiveness
the greatest cause of unnecessary radiation to the patient that can be controlled by the BMO is repeat exposures
gonad shields are used primarily to reduce the likelihood of genetic radiation effects
the 3 principle methods used to protect the limited operators from unnecessary radiation exposure is time, distance, sheilding
annual occupation dose limit for occupationally exposed workers is 5 rem or 50 mSv
personal dosimeters should be worn in the region of the collar on the anterior surface of the body and should be outside the lead apron
the NCRP recommended dose to embryo/fetus for a pregnant worker is 0.05 rem or 0.5 mSv
the exposure limit for the pregnant worker is 0.5 rem or 5 mSv
An explanation of the procedure and potential risks is called Informed Consent
Malicious spreading of information that results in defamation of character or loss of reputation is called Libel
threat of touching in a way that might injure someone is called Assault
unlawful touching of a person without consent battery
unjustifiable detention of a person against their will false imprisonment
when confidentiality of information has not been maintained or when the patient's body has been improperly exposed or touched Invasion of Privacy
information that reflects negatively on a patient's reputation defamation of character
good body mechanics lift with your legs, not your back
temporary state of low BP when a patient stands or sits up quickly orthostatic hypotension
for an infection to be transmitted there must be the following in the chain of infection infectious organism, reservoir of infection, susceptible host, means of transport of the pathogen
how is TB spread? airborne contamination
how is influenza spread? droplet contamination
how is meningitis spread? droplet contamination
an arthropod in whose body an infectious organism develops or multiplies before becoming infective to a new host (mosquito, tick) vector
the complete removal of all organisms and their spores from equipment surgical asepsis
the process if reducing the probability of infectious organisms being transmitted to a susceptible individual medical asepsis
the most effective way to prevent to spread of infection is good hand hygiene; hand washing
an electric steam chamber that seals tightly to achieve high temperatures under pressure to provide a means of sterilization for items that can withstand heat autoclave
what is MI myocardial infarction; heart attack