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BMO Review- Core
the form | Answer |
---|---|
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 |