Ch 8 radiographic equipment
What is a vertical?
Perpendicular to the plane of the horizon.
What is tube angulation?
Pivoting the tube at the point where it is attached to its support.
What is transverse?
Placed crosswise; situated at right angles to the long axis of a part.
What is anode?
Positive electrode of the X-ray tube
What is hard copy?
Radiographic image created on a polyester film medium.
What does sonography use?
sonar waves; cystic versus solid
what are R/F systems?
fluoro
What is autotracking?
A feature of modern X-ray systems that enables simultaneous vertical movement of an upright image receptor and overhead tube. x-ray
do fluoro images or spot images have lower patient dose exposure?
fluoro! they are usually grainier
what does CT scanning use?
radiation; many views; low-contrast resolution; tissue differentiation
what is the radiographic table?
radiolucent; 90-90 can tilt vertical in both directions; 90-45 is one side can only go to 45 degrees; floating
What is postprocessing?
Manipulation of medical images after they have been acquired through x-ray exposure in order to improve image quality and diagnostic yield.
What is digital imaging?
Acquisition of static images in an electronic fashion; conversion of images to a digital format for image manipulation, enhancement, storage, and networking.
What is a DR panel?
Common term for a flat- panel digital image receptor using either indirect or direct digital capture technology.
What is the picture archival and communication system PACS?
Computer network for the transmission, viewing, and archival storage of medical images; often integrated into a larger hospital information system (HIS) and radiology information system (RIS).
What is fluorscopy?
Examination by means of the fluoroscope, employing image intensification.
What is a cassette?
A Lightproof holder for the image receptor. In computed radiography, the cassette holds the reusable photostimulable phosphor imaging plate; in conventional film-screen radiography, the cassette contains intensifying screens and a sheet of film.
What is orthogonal?
A perpendicular relationship between the x-ray beam central ray (CR) and image receptor.
What is primary barrier?
A receptor of x-radiation that intercepts the primary beam and prevents exposure if not interlocked with the central ray of the x-ray beam. In fluoroscopy, the fluoroscopic digital panel or image intensifier tube are primary barriers
What is remnant radiation?
All radiation exiting the patient during exposure and ultimately striking the receptor.
What is a goniometer?
Angulation scale incorporated into the x-ray tube- head assembly to indicate the degree of x-ray tube angle relative to the image receptor.
what is the ALARA principle?
As Low As Reasonably Achievable
what is dual-energy subtraction radiography?
DR detector & high frequency x-ray generators allowing 2 rapid x-rays to be taken with different kVp settings; one low to look at calcifications & one higher to look at soft tissue, look at the net result of both images; looks at calcified anatomy
What is radiolucent?
Describes a material that easily transmits x-ray energy with very little absorption.
What is an x-ray tube?
Device that produces X-rays.
What is fluroscope?
Device used for dynamic radiographic examinations; usually consists of an x-ray tube situated underneath the x-ray table and an electronic image detector situated over the x-ray table.
What is a collimator?
Diaphragm or system of diaphragms made of an absorbing material; designed to define the dimensions and direction of a beam of radiation. This device consists of four rectilinear radiopaque blades that are adjustable to control the x-ray's field size and shape.
What is diode?
Electrical component that possesses polarity with a negative and positive terminal.
What is tether?
Electrical wire connection between a digital detector and the X-ray generator and computer.
What is an x-ray tube head?
Equipment consisting of the x-ray tube, collimator, and operator controls; permits manipulation of the x-ray tube in many directions for proper positioning.
What is spot film?
Equipment that permits the acquisition of static images during a dynamic fluoroscopic examination; images are recorded using film or are aquired digitally and stored electronically
What is positive beam limitation PBL?
Form of x-ray beam collimation of field size ensuring that the x-ray exposure field is no larger than the receptor size.
What is real time images?
Images in which dynamic patient motion is visualized instantly as fluoroscopic imaging is occurring.
What is latent image?
Invisible image created after x-ray exposure and before image processing.
what are some efforts manufactures have added to reduce patient dose in fluoro?
LIH, dose modulation, spatial frequency processing, pulsed fluoroscopy, & electronic shuttering
What is longitudinal?
Lengthwise, or along the long axis.
What is the overhead tube crane?
Mechanical support for suspending the x-ray tube and collimator assembly from the ceiling of the radiography room.
What is a cathode?
Negative electrode of the x-ray tube
What is pyrex glass?
Special type of glass that can withstand very high temperatures from the x-ray tube anode.
What is trendelenburg tilt?
Table tilt angle in which the patient's head and thorax are lower than his or her legs.
What is a flat panel detector?
Type of digital detector employing amorphous silicon or selenium material bonded with thin-film transistor technology for digital image creation and amplification.
What is soft copy?
Visualization of x-ray images using a video monitor (computer) for display and interpretation.
what is the control console & what are its features?
expressed in kilowatts power switch, selection of exposure factors, exposure button, initiate & terminate the exposure, audible & visual indication/display of x-ray exposure
what are the 2 tube support designs?
floor mounted & overhead tube support OTC
what interventional procedures are C-arm fluoro used for?
angiography, line placements, biopsies, myelography, arthrography
what are the advantages of tube design above patient & detector in table of fluoro set up?
detector can perform both fluoroscopic & static imaging, variable sid, fluoro controls can be operated remotely, less patient skin exposure b/c variable sid, image resolution, but scatter radiation is more intense to areas above the waist
what is the rotor-exposure-switch?
device that begins exposure; first part is rotor or prep switch, that causes the anode to rotate & prepares x-ray tube, 2nd switch is activated to begin exposure
what is diagnostic yield?
diagnostic info must outweigh the input factors; diagnosis over risks
what is tomosynthesis?
digital radiographic procedure that acquires as many as 60 low-dose projection images during a single x-ray tube-detector sweep of the patient in a single breath hold
What is Bucky mechanism?
grid that is an integral part of the x-ray table, located below the tabletop and above a cassette receptor tray. it decreases the amount of scatter radiation to the IR, so it improves quality and contrast. moves during exposure so no grid lines appear on the image
what is a milliamperage?
indicates amount of current supplied to x-ray tube; 50-1000 mA with incraments of 100... most techs only go up to 400; quanity
what does nuclear medicine use?
injectables
what is conditioning?
intense white light to "erase" the cassette based plate; receptors r smaller for CR
What can portable c-arms be used for?
interventional procedures like pain management, orthopedic surgeries, vascular line placements, & etc
what does radiography use?
ionizing rays
what does MRI use?
magnetic mimicking; patient is source of information; good for inflammatory processes; distinguishes between subtle tissue differences
what is 90/15?
one side can only tilt 15 degrees and the other 90
what is kVp?
penetration power; 30-150 kVp; quality
what happens to the x-ray system when first switch is pressed to the 2nd step?
the anode begins to spin at a high rate, and the cathode filament heats up to the selected mA & during the second step, a large potential difference kVp is applied across the x-ray tube, causing the electrons to travel from cathode to anode at high speed, hits target and produces x-radiation
what is a primary barrier?
the image receptor to the x-ray beam during fluoro, when the detector is above patient and tube in table
what is the design of the x-ray tube?
tube is made of pyrex glass, inside a lead-lined tube housing & has high-voltage electrical cables attached at each end. anode target + (end) and cathode filament - (beginning) side. overhead tube crane OTC suspends tube
what are the different wall cassettes?
wall-mounted bucky system & cassette holder
what kind of radiation is of any clinical value?
whats absorbed in the detector & able to be converted into an image
what is the cathode filament?
where electrons are produced, negative; tightly wound tungsten wire helix
what is the collimator assembly?
x-ray beam limiting device; controls size and shape of x-ray field, "coning down" means smalling the size of field; has sid & goniometer (angle) on it, "shadow shield" is the shadow cross & automatic exposure controls AEC (the squares on chest wall)
what are the x-ray machine features?
x-ray tube & tube support collimator assembly (what the tech moves) radiographic table control console/generator upright IR holding system