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Intro to Rad Chp 8
Radiographic and Fluoroscopic Equipment
Question | Answer |
---|---|
What is the primary role for a radiographer? | The manipulation of expensive, high-technology x-ray equipment |
Generic components of radiographic systems include: | X-ray tube, collimator, x-ray table, control console, Tube stand |
What part of the radiographic system produces the x-rays and radiation? | X-ray tube |
What is the x-ray tube made of? | Glass or aluminum and encased inside a sturdy metal housing. |
the two primary components of the x-ray tube | Anode & Cathode |
Positive electrode or terminal; where the x-rays are emitted | Anode |
negative-electrode or terminal; where the electrons are liberated | cathode |
How are x-rays created? | The tube will convert electrical energy (electricity) to x-rays |
- controls the quantity or number of x-rays | mAs |
-controls the strength or penetrating power of the x-rays | kVp |
x-ray beam-limiting device attached directly below the x-ray tube | collimator |
-controls the size and shape of the x-ray field coming out of the tube | collimator |
diaphragm or system of diaphragms made of an absorbing material | collimator |
designed to define the dimensions and direction of a beam of radiation device consisting of four rectilinear radiopaque blades that are adjustable to control xray field size and shape | collimator |
-act of adjusting the collimator to increase or decrease the field size is referred to as | collimating or coning |
increase collimation | making a smaller field size |
The __________ decreases or limits the field size and reduces unwanted scatter radiation from reaching the IR or cassette. | Collimator |
- automatic collimation systems | Positive Beam Limitation ( PBL) |
allows the x-ray unit to detect the size of the IR and automatically limit the x-ray field size to that size to minimize patient dose | PBL - Positive beam limitation |
6 types of x-ray tables: | tilting, nontitling, free-floating, stationary top, adjustable, nonadjustable |
- move in two directions -may be buttons for table movement or foot switches | Free-Floating or moveable table tops |
2 types of titling tables are: | 90-90 (tilt from horizontal to vertical in either direction.) 90-30 (tilt vertical one way and 30 deg another) |
-located below the table top and above the cassette tray | bucky mechanism |
-works as an oscillating grid device to decrease the amt of scatter radiation reaching the IR by moving or vibrating during the exposure | bucky mechanism |
using the bucky system will do what to contrast? | increase it |
another name for bucky tray | cassette tray |
-holds IR in place under the x-ray table & keeps it center under the table | bucky tray |
the device that gives the operator command of the x-ray machine | control console |
5 generic controls on the control console: | main power, kVp, mA, time, rotor-exposure switch |
what is technique selection? | manipulation of mA, kVp, and time |
What two components can be formed to create mAs? | mA and time |
Main power switch is usually located? | on the wall above the control console |
Machine power is usually located? | on the control console |
1kVp = _____ V | 1000 |
kVp will range from ___ to ___ on most machines | 30, 150 |
major kVp will change in steps of? | 10 |
minor kVp will change in steps of? | 2 |
1000 mA = ____ A | 1 |
control consoles will range from ___ mA to ___ mA | 10, 1200 |
mA is usually in increments of... | 100 ( 100, 200, 300, etc) |
most routine diagnostic radiography is done: | btwn 100 and 400 mA |
the device that begins the exposure | Rotor-exposure switch |
-contains two differnt exposure switches that are mechanically interlocked so one must be activated before the other | roto-exposure switch |
-causes the anode rotor to rotate and prepares the anode for the exposure factors/ takes 1-2 sec | rotor switch |
begins the exposure | exposure switch |
-automatically terminates the exposure -termination of the exposure must be indicated both audibly and visually | timer |
How do you avoid ending the exposure too soon? | Get in the habit of not releasing the exposure switch until the audible tone or light message indicates |
4 types of tube movements: | longitudinal, transverse, vertical, tube angulation |
-travel is moving the x-ray tube lengthwise to the technologist's left or right or toward the patients head or feet | longitudinal |
-travel is moving the tube at right angels across the table/towards or away from the technologist | transverse |
-travel is moving the tube up toward the ceiling or down toward the floor | vertical |
-pivoting the tube at a point where it is attached to its support | tube angulation |
two types of tube locks: | electrical or Mechanical ( sometimes both) |
The student must make sure the central ray (tube) is _____ to the center of the bucky tray when the tray is being used. | centered |
-the presentation of continuous or dynamic radiographic image | fluoroscopy |
What is added during an fluoroscopy exam? | additl fluoroscopy x-ray tube, placed under the table; an image intensifier |
-allows the radiologist to obtain static radiographs during dynamic fluoroscopic exams | spot film device |