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171
films
| Question | Answer |
|---|---|
| A curve representing the relation between the energy absorbed by a film during exposure and the resultant density is the | characteristic curve |
| The base of x-ray film is typically | polyester |
| The compound used in an intensifying screen as a phosphor is | calcium tungstate |
| The emulsion of the x-ray film contains | silver bromide |
| As the thickness of the active layer of crystals in an intensifying screen is increased, the sharpness of the image is | decreased |
| A film emulsion with a steep characteristic curve (sloop of the straight line portion is steep) usually indicates | higher contrast |
| A characteristic curve located further to the right on the y-axis indicates a | slow IR |
| A radiograph is made at 85 kVp, 25 mAs without a grid (GCF of 1). If an 8:1 grid (GCF of 4) is added, what change in technique would occur | 85 kVp @ 100 mAs |
| The efficiency of a grid depends greatly on the | grid ratio |
| The ratio of the height of the lead strips to the distance between lead strips is the | grid ratio |
| Film latitude increases as | screen speed decreases |
| The purpose of the reflective layer in the intensifying screen is | reflect the light from the screen back onto the film |
| The proper way for stacking film during storage is | on edge |
| Which of the following does NOT affect the intensification factor or speed of an intensifying screen? | size of radiation field |
| In the development of exposed x-ray film, the action of the developer reduces silver salts to | black metallic silver |
| Three of the following are advantages of automatic processing of radiographic film and one is not. Select the one that is NOT an advantage. | It allows for better quality control. |
| The order of automatic processing is: 1. Fixation 2. Drying 3. Washing 4. Development | 4, 1, 3, 2 |
| What is the purpose of washing during automatic processing? | Remove the unexposed silver bromide crystals |
| The average energy of the primary x-ray beam depends upon 1. part film distance 2. the set kVp 3. focal film distance 4. the amount of total filtration of the beam | 2 and 4 |
| Which of the following is decreased with larger field size? contrast fog density | contrast |
| Shape distortion is controlled by | alignment |
| Of the following, the best recorded detail will be provided by a screen with a speed of 800 400 200 100 | 100 |
| If during a radiographic examination, the x-ray tube is switched from the large to small focal spot size, then | the penumbra will be reduced |
| Which of the following may cause poor film screen contact? foreign bodies under the screen a warped cassette front a wrinkled screen caused by moisture | all of the above |
| A criteria for obtaining satisfactory radiographic quality is | maximum sharpness and true shape of the image |
| The main advantage of a moving grid compared to a stationary grid of the same ratio and frequency is greater tube angulations are permitted grid cutoff is reduced grid lines are blurred | grid lines are blurred |
| Which type of grid pattern will result in a radiograph with the least amount of primary beam cutoff? | focused |
| When the greatest reduction of scattered radiation hitting the IR is required, a/an _______ ratio grid should be used. | 16:1 |
| In order to avoid the appearance of grid lines when using a moving grid, the Bucky tray motion must commence | before the exposure begins |
| When grids are utilized, the technical factors must be adjusted because | scatter absorption increases |
| A given grid has grid strip thickness of 10 mm, a grid interspace of 20 mm and height of 160 mm. What is the grid ratio? | 8:1 |
| If a 12:1 ratio grid is substituted for an 8:1 ratio grid, and the same technical factors are employed, the film will process a higher | contrast |
| Tube angulations techniques are often required during many normal radiographic procedures. For this reason, the least commonly employed grid for a general purpose room would be a | crossed grid |
| The appearance of grid cutoff when focus grids are employed is likely when the tube is 1. angled along the grid strips 2. off centered to the grid 3. used at the wrong distance | 2 and 3 only |
| The advantage(s) involved with the use of a radiographic grid is/are 1. improved contrast 2. lower patient exposure (radiation dose) 3. reduced scatter production | 1 only |
| The contrast improvement that can be obtained with a particular grid is dependent upon the 1. kVp used 2. patient thickness 3. size of field | 1, 2 and 3 |
| In general, about _______ of x-ray film's exposure is due to the light emitted by the screen's phosphors. | 95 - 98% |
| The emission of light from a phosphor after the incident radiation exposure is terminated is called | phosphorescence |
| Rare earth phosphors are a significant improvement over calcium tungstate screens. This is due in a large part to their high | conversion efficiency |
| As crystal size in an intensifying screen increases, recorded detail will tend to | decrease |
| The light emitted by an intensifying screen should correspond with the film's light sensitivity. This is called | spectral matching |
| The principle action of the crystals found in intensifying screens is the conversion of | x-rays into visible light |
| The ratio of exposures required to produce the same film density with and without screens is termed the | intensification factor |
| The front of any type of film holder must be covered in a light tight substance that is ________________ to x-radiation. | radiolucent |
| In a cassette, the thin layer of foam rubber (felt) behind each screen serves to | improve film-screen contact |
| A screen is to be manufactured with a thicker crystal layer. This will increase the | screen speed |
| The majority of screen type radiographic film consist of a film base and | dual film emulsion |
| The major factors that will cause a variation in film speed is/are 1. crystal size 2. emulsion thickness 3. base material 4. base tint | 1 and 2 |
| The latent image is formed by the action of x-rays and the | crystals in the film emulsion |
| A H&D curve is used to compare the film factors of 1. speed 2. contrast 3. latitude 4. sensitivity | 1, 2, 3 and 4 |
| A characteristic curve is made by plotting _____ and the resulting _____. | log relative exposure density |
| Small amounts of impurities are found in the silver halogen crystals of film. These are called | sensitivity specks |
| The sloop or steepness of the characteristic curve of a radiographic film is used in the determination of its | film contrast |
| A protective coating placed on film helps to increase durability prevent scratching reduce static | all of the above |
| The stage of development in which the latent image is converted into the manifest image is called | development |
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wolfe9ah