LMRT State Review Questions and Answers 100% Pass

LMRT State Review Questions and Answers 100% Pass indicator number how much radiation was absorbed into the phosphors image stitching stitching together multiple images - useful for scoliosis studies of the spine, long bone studies or angiographic imaging of peripheral vasculature. - to view as a single image. image annotation allow the technologist to inset preset text or manual text on the image contrast resolution (digital) Ability to distinguish anatomic structures having similar subject contrast spatial resolution Refers to the amount of detail present in any image.Phosphor layer thickness and pixel size determines resolution in CR. pixel A single square within a matrix matrix a series of very small boxes that form a digital image direct conversion one step process in DR where flat panel detectors convert the x-ray energy directly to an electric signal using an amorphous selenium detector for immediate viewing charged coupled device component which light enters and is converted into video or electronic signal thin film transistor used to read charges collected during an exposure photodiode A silicon solid state device sensitive to light. Converts light into an electrical signal. scintillator Amorphous silicon requires a _____ such as cesium iodide or a rare earth intensifying screen composed of gadolinum and lanthanum with oxysulfides. This also converts x-rays to visible light. flat panel detector a type of digital detector employing amorphous silicon or selenium detector material, bonded with thin-film transistor technology for digital image creation and amplification density It is the degree of blackening of a radiograph resulting from radiation exposure and processing and one of the two photographic properties that comprise visibility of detail. automatic exposure controll a device that measures the quantity of radiation that reaches the image receptor and automatically terminates the exposure when the image receptor has received the required radiation intensity high frequency generator , What uses AC and DC power converters to change the incoming line from 60Hz to 6000Hz? three phase generator ... single phase generator produce a pulsating current that alternates from positive to negative and are power by a single source of ac diode A device that permits current to flow through it in only one direction rectification The process of converting AC to DC. filament circuit low-voltage circuit; uses 3-5 volts, regulates the flow of electrical current to the filament of the x-ray tube; controlled by mA settings high voltage circuit Purpose is to provide high electrical potential needed to accelerate electrons from cathode to the anode. Controlled by kVp. autotransformer Provides a variable yet predetermined voltage to the high-voltage step-up transformer. It acts as the kilovoltage selector. exposure switch closes the circuit and allows current to flow though primary side of step up transformer recorded detail Sharpness of the structural edges of the radiographic image. Describes the degree of geometric sharpness or accuracy of the structural lines recorded in the image. exposure time ... sid ... OID ... quantom mottle refers to the random nature by which x-rays interact with IR, under the control of radiographer and is principal contributor to radiographic noise (the use of high mAs, low kVp settings and slower IR's reduces ____) control consol The unit inside the control booth, where the operator sets all of the exposure techniques, such as: kilovolts peak, milliampheres, and exposure time. contrast shades of gray on an image x ray generator ... heat units The formula, mA x kVp x time, is used to determine what the maximum heat capacity of the anode of the x-ray is rated in terms of: heat units back up timer what is set in case of failure in AEC phototimer ... umbra actual anatomical area on a film penumbra The blurred/ indistinct area that surrounds an image prime factors What is the term for the three principal factors that affect xray emission that are under direct control of radiographer? prime factors kvp ma time SID anode heel effect It alters the intensity of radiation and therefore the density between the anode and cathode ends of the x-ray tube. Due to the geometry of an angled anode target, the radiation intensity is greater on the cathode side. thermionic emission The process of "boiling off" of electrons from the filament coils focusing cup small oval depression in the cathode assembly, the negative charge of the focusing cup helps direct electrons toward the anode in a straighter less divergent path. bremsstrahlung X-rays that are produced when a projectile electron is slowed by the electric field of a target atom nucleus 15% rule used to maintain exposure to the image receptor and maintain radiographic film density. Increasing kvp 15% requires mas to decrease by 50%, decreasing kvp requires mas to increase x2. inverse square law Intensity of the x-ray beam is inversely proportional to the square of the distance between the source of x-rays and the image receptor. characteristic radiation Produced when a high-speed electron dislodges an inner-shell electron from a tungsten atom and causes ionization of that atom. Occurs only at 70 kVp and above. focal track The tungsten focal area all around the beveled edge of the rotating anode actual focal spot An area on the target surface that is struck by the electron stream effective focal spot The area of the focal spot that is projected out of the tube toward the object being radiographed is the: target angle The slant of the anode surface; between 7 and 17 degrees, with 12 degrees the most common; it affects the tube's heat capacity, the sharpness of the radiographic image, and the maximum size of the x-ray beam. potential difference In order to get electrons to flow, this is required. frequency How many waves can pass a given point per second, measured in Hertz (Hz) circuit ... electromagnetic conduction when the direction of current flow is reversed,creating alternating current primary radiation X-ray beam that leaves the tube and is attenuated, except by air. It's direction and location are predictable and controllable. tube port X-rays exit the tube housing through an opening called the velocity wavelength times frequency atomic number A unique number identifying the number of protons in the nucleus of an atom. This number identifyies the atom. atom Basic unit of matter; made of three sub-atomic particles (neutrons, protons, and electrons) matter Anything that has mass and takes up space molecule A particle made of two or more atoms bonded together. crest Highest point of a wave amplitude ... coolidge tube hot cathode x-ray tube; vacuum tube that allowed x-ray intensity and energy to be selected separately and with great accuracy crooks tube What type of tube was used when x-rays were first discovered? electric energy Energy of electric charges. thermal energy Energy from heat potential energy "stored energy" kinetic energy Energy of motion direct current Current that flows through a conductor in one direction only. alternating current Current that flows through a conductor in two directions that are periodically altered. resistor A material or device of a circuit that henders or opposes the flow of electricity asrt The curriculum being taught in your radiography program is based on the national radiography curriculum written by which professional organization? asrt American Society of Radiologic Technologists arrt American Registry of Radiologic Technologists arrt Give the registry exam and your credentials upon passing the exam are: ? jrcert Joint Review Committee on Education in Radiologic Technology - educational standards and accreditation ionization process in which an atom gains or loses an electron rectification The process by which alternating current is changed to pulsating direct current central ray line that is perpendicular to the long axis of the x-ray tube and is in the center of the x-ray beam. X-Ray beam an imaginary line in center of x-ray beam and peerpendicular to long axis of the x-ray tube. Image receptor ______ _______ - medium used to capture the image for recording, such as x-ray film or a digital imaging plate. An interpretation device that intercepts the x-ray photons that are able to exit the patient. remnant radiation All radiation exiting the patient during exposure and ultimately striking the receptor. scatter radiation A form of secondary radiation that occurs when an x-ray beam has been deflected from its path by interaction with matter wilhem conrad roentgen Discovered x-rays on nov 8, 1895. cathode a negatively charged electrode that is the source of electrons in an electrical device anode a positively charged electrode by which electrons leave an electrical device neclear energy ... chemical energy Energy available in molecules for release in a chemical reaction; a form of potential energy bucky ... step up transformer ... step down transformer ...