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