| Question | Answer |
| Replenishment system | Replaces chemicals that are depleted through the chemical reactions of processing, oxidation and evaporation. |
| Deficiency of screens to produce light | As screens age, their phosphors decrease in activity. |
| Characteristic interaction | an incident electron interacts with an inner-shell electron, knocking out the inner shell electron and continuing in a slightly different direction, which creates a hole in the inner-shell, making the shell unstable. |
| an increase in Kvp will ___ density | increase |
| Magnification size distortion is controlled by | positioning the body part and tube to maximized SID while minimizing OID. |
| What happens if fixer is not washed off? | can result in silver stains or a yellowing of the emulsion after a few years. |
| Volume replenishment system | is used for high volume units. |
| Why should the lid of the processor should be propped open whenever the processor is not in use? | Because when processor is shut down, excessive condensation can occur as it cools. |
| Latitude | is the range of exposures that will produce densities within the diagnostic range. |
| AEC | : the function of aec is to eliminate the need for the radiographer to set an exposure time |
| Dmax | the maximum density the film is capable of recording. |
| Sensitometric curve | radiographic relationship between amount of exposure and resultant density on the film (D log E curve, characteristic curve, Hurter and Driffield curve) |
| speed and number of sensitivity specks are____ proportional | directly |
| Pi line: | dirt or chemical stains on rollers |
| Quality of photons | kvp |
| Foreshortening occurs when | the part is improperly aligned. Changes in the tube angle cause elongation, never foreshortening. |
| Brittle appearance | improper dryer temperature or hardener in the fixer |
| Penetrometer | aka step wedge. a series of increasingly thick uniform absorbers. |
| Characteristic cascade | : the reaction of electrons dropping into holes created during a characteristic interaction until there is only a hole in the outer-shell. |
| What is the trace of passage way in the processor? | Transport (moves film through developer, fixer, wash, and dryer) |
| Contamination of developer | only 0.1 % of fixer in the developer tank will destroy the ability of the reducing agents. a film will appear extremely gray. |
| What is fluorescence? | type of luminescence, is the instantaneous emission of light. Light is emitted within the time it takes an electron to complete one orbit. |
| Temperature control system | Developer, washer and dryer required precise temperature. developer (most critical) wash water is maintain at 3C (5F) or lower. |
| What are the 2 major chemicals for development. | Phenidone and Hydroquinone |
| Decreasing SID will _____ IR exposure | increase |
| Resolution and speed are affected by? | concentration of the crystals , phosphor crystal size, layer thickness, |
| Layers of the screen | 1. Base 2. Reflective layer 3. phosphor 4.protective coating |
| Speed is controlled by what? | activity of phenidone because affects the toe of the D log E curve. |
| increasing mAs will _____ contrast | no change |
| High resolution | small crystal size and thin emulsion |
| Black metallics | When a silver ion obtains en extra electron, it is converted to a stable black metallic silver atom. |
| Base plus fog | is the density at no exposure or density that is inherent in the film. |
| Generator | : device that converts mechanical energy into electrical energy |
| What is Isotropic emission? | refers to radiation emitted with equal intensity in all directions. |
| What is the approximate time for automatic and manual developing? | Automatic: 22 seconds
Manual: 5 Minutes |
| Resolution | ability to accurately image an object. unit line pair per millimeter lp/mm. Small crystals=darken small area of film. Large crystals= darken large areas. |
| Developer temperature | 92 to 96 F (33 to 35 C) |
| How is the replenishment system activated? | when the film enters the processor, the entrance rollers activate a microswitch or an infrared sensor. |
| Spectral emission | is an indication of precise wavelength of light emitted by the phosphors. |
| U.S. public law requires | that generators automatically terminate AEC exposures at 600 mAs nor 60 kilowatt seconds above 50 kVp and 2000 mAs below 50 kvp. |
| Normal life of intensifying screen phosphors is? | 5 to 7 years |
| Thermionic cloud | is produced by the cathode. Conduction of high voltage to the gap |
| Curtain effect | improper squeezing of processing chemicals of film |
| Latitude and contrast are _____ related | inversely. as contrast increases, latitude tends to decrease. |
| Non-conducting materials are called | insulators. |
| What controls speed of transport system? | Is control by the speed of the motor and gear reduction system used. Drive system turns the rollers in the processor. controls the time each chemical is immersed in each chemical solution. |
| improper squeezing of processing chemicals of film | pressure caused by irregular or dirty rollers |
| PH of solutions | Developer-Reducing agents 10.0 to 10.5. Fixer-Activator (4.0 to 4.5)
Concentrating solution containing hydroquinone has a PH of 12.0 |
| Silver halides | have a negative exteriors (where bromide and iodine are located) and positive interiors (where silver ions are located. |
| AEC cells, when more than one cell is used | the signals from the cells are sent to a special operational amplifier which sums the voltages received from each cell. Divides by the # of cell that have been activated, and then terminates the exposure. |
| The length of a conductor has ____ proportional relationship to resistance | directly |
| Phenidone | Reducing agent, rapidly produces fine detail shades of gray. |
| an increase in mAs will _____ density | increase |
| What are the reducing agents in the developer? | Phenidone and hydroquinone. |
| Factors that affect recorded detail are | SID, OID and focal spot size, image receptor and motion. |
| Chemical Fog | The effect of a film when unexposed silver halides are reduced. |
| Umbra | : is the distinctly sharp area of a shadow or the region of complete shadow. The umbra receives essentially no photons. |
| Speed | The amount of density a film produces for a given amount of exposure in the film speed. |
| Three subsystems of Transport system | Transport racks, crossover networks, drive system. |
| increasing SID will _____ IR exposure | decrease |
| Milky appearance | : underreplenished fixer |
| Low Contrast | Many shades of gray, decreased contrast, high kvp, long scale contrast. |
| film speed and thickness layer are ______ related. | directly |
| Quantity of photons | mAs |
| Film speed and crystal size are _____ proportional | directly |
| Construction of various layers of screen | 1. Base: Polyester plastic 1mm thick. 2. Reflective layer: magnesium oxide or titanium oxide 25um thick. 3. phosphor layer: 150 to 300 um. 4. Protective coat: plastic 25 um thick. |
| Bremstrahlung interaction | an incident electron reacts with the force field of the nucleus, causing the electron to slow down, diverting the electron’s course; the electron loses energy and changes direction; the energy lost is the “braking”. |
| Flood replenishment system | is used for low volume units. |
| Low resolution | large crystal size and thick emulsion. |
| The minimum change necessary to cause a visible change in density must be? | 30 % of mAs or other influencing factor that would equal this change. |
| Types of filtration | Inherent (inside the tube), Added (outside tube), Compound (2 or more materials, placing high z# closest to the tube and lowest Z# closest to the pt), compensating (wedge and trough). |
| Yellow-brown drops on film | oxidized developer |
| Backup time | should be set at 150% of the anticipated manual exposure time |
| Density | one of the two photographic properties that comprises visibility to detail. Overall balckening from the black metallic silver deposited in the emulsion. |
| What are the critical time periods is a processor. | the most critical time period is the Developer: 20-25 sec.
(Fixer: 20 sec. Wash: 20 sec. dry: 25-30 sec.) |
| What is acetic acid, where can we find it and why we use it for? | Is used as the activator in the fixer. maintaining an acidic PH of 4.0 - 4.5 to enhance the function of the clearing agent. Also reduces agents from continuing to function when film is immerse in film. |
| Controlling factor of density | mAs |
| Penumbra | : Is the imperfect, unsharp shadow surrounding the umbra. Receives more photons at the outer edges w/ progressively fewer photons toward the umbral area. |
| Melting of the anode occurs due to | rotor-bearing failure. Also when temperatures exceed the melting point of tungsten melting will occur. (long used at high temperatures) |
| Half Value Layer | is the amount of absorbing material that will reduce the intensity of the primary beam to one-half its original value |
| Exposure switch | remote control device that permits current flow through the circuit. initiates exposure. |
| How the 90 second rapid processing (1965)became possible? | Developing of new chemistry and emulsions.
Faster drying thanks to the polyester of film base. |
| Densitometer | instrument that provides a readout of the amount of blackening (density) of the film. |
| Sharp increase or decrease in OID | dirty or warped rollers, leaves sludge deposit on film
Gray fog: improper processing chemistry |
| The movement of electrons is facilitated by | material that allow electrons to flow easily. This materials are known as conductors. |
| Rectification | : process by which alternating current is change into pulsating direct current |
| Why are rare earth screens preferred? | because they have greater absorption abilities, intensification factors, and conversion efficiency. Rare earth screens use phosphors with z# of 57-71. difficult to isolate. |
| Intensifying screen characteristics | Resolution, speed, contrast and latitude. |
| What is phosphorescence? | type of luminescence.Is delayed emission of the light. phosphorus continues to emit light after the incident x-ray photon energy has dissipated. |
| Resistance | the amount of opposition to the current in the circuit |
| High contrast | Fewer shades of gray, increased contrast, low kvp, short scale of contrast. |
| Reflective Layer | Layer of material used in an intensifying screen to reflect light towards the film. |
| an increase in kvp will ______ contrast | decrease |
| what does Wire mesh test tool checks for? | Is used to check good screen- film contact. Areas of poor screen will appear blurry and cloudy. |
| Current | the quantity or # of electrons flowing. |
| Sensitometer | equipment design to expose a reproducible uniform, optical wedge onto a film. has controlled intensity light source. |
| Hydroquinone | Reducing agent, slowly produces heavy densities. (black tone) |
| Straight line portion | between toe and shoulder.Useful range of densities. |
| How cassettes should be store? | on end. |
| screen lag or afterglow | delayed phosphorescent emission, common in older intensifying screens. |
| Atomic number for phosphors | High atomic number is desirable to increase the probability of an incident x-ray photon interactions. |
| Overhead support system | is the most flexible and costly |
| What is luminescence? | Is the ability of a material to emit light in response to excitation. |
| Greasy appearance | inadequate washing |
| Silver halides thats have fewer than ____ silver atoms on their sensitivity speck are unable to open a gate and remain undeveloped. | 3 |
| Filtration: | is the process of eliminating low energy photons by the use of aluminum. Reduces patient dose . |
| Distortion | is the 2nd of the two geometric properties affecting radiographic image quality. Is misrepresentation of size or shape. |
| Guide shoe mark | improper positioning or springing of guide shoe in turnaround assembly |
| Configuration | determining the location of the AEC chambers is important. If plastic inserts are not provide to determined the location of aec’s a tech must take an image without a body part , exposed at very low Kvp for maximum contrast. |
