rads
Terms
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copy deck
- who is credited for the discovery of radioisotopes?
- Marie Curie
- Who is credited for the discovery of x rays?
- WC Roentgen
- Define radioactivity
- the process by which atomic nuclei shift from a less stable to a more stable nuclear configuration, emitting ionizinfg radiation in the process
- What is the primary difference between x rays and gamma rays?
- Source: X rays from electron interactions. gamma rays from the atomic nucleus
- What strikes the target in an x-ray tube to cause x-ray production?
- electrons
- What results in the diagnostic x-ray beam containing a wide range of energy levels?
- Bremmstrahlung
- From which components of the x-ray tube do x-rays originate?
-
anode
focal spot - What does increasing the kVp do to the x-ray beam?
- It increases the number and energy of the x-ray beam
- What is the primary advantage of keeping x-ray exposure time short?
- Decreased motion
- What is the purpose of using a grid in radigraphy?
- Decrease scatter radiation which can cause fog and loss of detail
- What is the purpose of using intensifying screens?
- It allows the user to reduce the amount of radiation required to make a diagnostic image by converting x-rays to visible light which is better for exposing films
- name 3 types of intensifying screens
-
phosphor
calcium tungstate
rare earth - silver halide is a form of what?
- radiographic film
- Define opacity interface
- the visible line on a radiograph between two objects of different radiographic densities that are adjacent
- What is ultrasound?
- an imaging technique that uses unaudible, high frequency, low intensity sound waves.
- Define radiation
- energy moving through space or matter
- define silhouette sign
- lack of visualization of margins due to structures of the same opacity lying adjacent to one another
- Name 3 radiographic abnormalties that may occur in pressure areas of the joint resulting from DJD
-
Thinning of joint space
subchondral bone erosion
subchondral bone sclerosis - define osteophyte
- mineralization formed at the margin of the articular cartilage within thickened, vascularized cartilage that has developed as part of a degenerative process
- define enthesophyte
- mineralization at the attatchment of joint capsules, ligaments, tendonsand muscles, typically due to chronic abnormal tension or trauma.
- define fog
- film density that is unrelated to the subject
- what is density?
- darkness on a radiograph
- define detail
- refers to the sharpness of an image
- What is distortion?
- Deviation of the readiographic image from the true size and shape of the subject
- What is contrast?
- the difference between the shades of black, white and grays in a radiograph
- What is opacity?
- the property of a substance to absorb radiation
- What is opacity interface?
- difference in opacity between 2 adjacent structures
- What is a penumbra?
- The shadow caused by geometrical divergence of x-rays which causes gradual changes between shades of gray at the edges
- With a given exposure how is high speed film different from low speed?
- high speed has thicker silver halide layers and larger crystals resulting in more density but less detail/definition. Low speed is opposite
- What is phosphor?
- A phosphorescent material used in intensifying screens to convert x-rays to visible light in order to reduce the amount of radiation required to make a diagnostic radiograph
- What is scatter?
- radiographic density formed from extraneous radiation from the patient, other objects, etc
- What is FFD?
- the distance from the focal spot to the film
- What is a grid?
- a thin sheet or plate constructed of alternate strips of lead and radiolucent material interposed between the subject and the film. they prevent scatter radiation from reaching the film
- When the focal film distance increases there is less intensity in the beam producing less exposure to the film. This can be calculated using what?
- Inverse square law
- What is OFD?
- the distance from the object to the film
- describe the anode of an x-ray tube.
- The anode is the positive pole of the x-ray tube that attracts the electrons from the filament
- What is the velocity of sound in soft tissues?
- 1540 m/sec
- regarding ultrasound, what is acoustic shadowing?
- an artifact that is commonly seen when the ultrasound beam encounters a mineral structure
- What is the best view to use to see compartmentalization of the stomach in GDV?
- right lateral
- Pseudo ulcers in the dog are actual what?
- outpouchiings of the doudenum
- When can ossification of fetal structures be identified radiographically?
- 42 days
-
true or false
A splenic mass will cause a mid abdominal mass - true
- Can a normal non gravid uterus be identified on a radiograph?
- no
- How long after surgery can free peritoneal gas remain?
- 2-3 weeks
- What are 4 causes for generalized increased opacity in the abdomen
-
peritonitis
emaciation
immature-brown fat
ascites - give 2 differentials for a mass effect originating from the caudal ventral abdomen of a male dog
-
prostatic carcinoma
benign prostatic hyperplasia - Name 2 duodenal abnormalties that may be seen on an upper GI study that would make you consider paancreatitis
-
Doudenum displaced to the right of the abdomen
Less detail of the duodenum due to swelling and damage from pancreatic enzymes - What are 2 diseases that could result in retention of contrast medium in a discrete area of the prostate gland?
-
prostatitis
prostatic carcinoma - What are 4 reasons for the diaphragm to not be visible?
-
alveolar pattern in the caudal lung field
pleural effusion
mass in the caudal thorax
diaphragmatic hernia - Which radiopharmaceutical is used in a nuc scan of the muscluloskeletal system---up to phase three?
- Tc-99m MDP
- What radiopharmaceutical is used in a nuc scan of the lungs?
- Tc-99m MAA
- what radiopharmaceutical is used in a nuc scan of the kidneys?
- Tc-99m DTPA
- Which rays or particles come from the atomic nucleus?
-
gamma rays
beta
alpha - What is the HVL (half value layer)s
- thickness of a substance that will stop half the x-rays or gamma rays in a beam
- name 4 ultrasound artifacts
-
distant enhancement
acoustic shadowing
reverberation
slice thickness - Mineralization of the prostate is highly suggestive of what?
- neoplasia
- what is the equation for acoustic impedence?
- velocity x tissue density
- What is attenuation?
- It occurs when sound waves lose strength as they travel through tissues
- What is mAS?
- milliamps per second. This controls the current flowing through the filament which either reduces or increases the number of electrons available in the electron cloud
- What are the advantages of using a water soluble media for contrast studies?
-
safer if aspirated
safer if leaked into body cavities
more palatable - What are some advantages of using a barium suspension in contrast studies?
-
Easier to see on radiographs
binds well to damaged tissue
barium can be used for many different studies so availability is high - Given a whole body radiation exposure of 250 rads, what would serial cbc's demonstrate, from earliest to latest?
-
lymphopenia
neutropenia
thrombocytopenia
anemia - What is a rem?
- unit of radiation exposure
- what are 2 units of quantity of radioactivity
-
curie
becquerel - What is an electron volt?
- unit of energy of ionizing radiation
- X-rays, gamma rays, and visible light have 3 things in common. What are they?
-
Have velocity same as light
energy is related to wavelength
photons