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RAD EQUIPMENT/ IA&P
RAD EQUPIMENT and IA&P Worksheet Questions. May add more terms/definitions.
| Question | Answer |
|---|---|
| When the mAs is increased, x-ray quantity: | INCREASES proportionately. |
| When the kVp is increased, x-ray quantity: Why? | INCREASES, while quality also increases. Because an INCREASE in quantity of kVp, produces short wavelengths, which increases the penetrating power. |
| When distance is increased, x-ray quantity at that distance: | Decreases in proportion to distance squared |
| When x-ray tube filtration is increased, x-ray quantity: | DECREASES |
| In general, x-ray quantity will increase with a/an: | Increase in kVp |
| Which of the following does not affect x-ray quantity? a. Filtration b. kVp c. mAs d. Radioactivity e. Time | d. Radioactivity |
| To maintain a constant IR exposure, what percentage increase in kVp should be accompanied by a reduction of one half in mAs? | 15% |
| MATH: An extremity radiograph requires 5 mAs and results in an exposure of 180 mGy. What will be the exposure if the technique is changed to 7 mAs? | 1. First determine your olds and your news. We are working with mAs and Intensity (mGy). 2. Next, figure out if it is Direct or Indirect (mAs and Intensity are DIRECTLY PROPORTIONAL) 3. Olds on the top, News on the top. SOLVE! ANSWER: 252 mGy |
| MATH: An abdominal view is taken at 82 kVp at 200 mAs and results in a patient exposure of 1.32 mGy. To improve contrast, the kVp is reduced to 70, but IR exposure needs to be maintained. What is the new patient exposure? | 15% rule was used to decrease kVp. So, an decrease in kVp = DOUBLE the mAs (200 is now 400 mAs) mAs and Intensity = DIRECTLY proportional Olds on the top, News on the bottom. SOLVE! ANSWER: 2.64 mGy |
| MATH: A portable chest x-ray is taken at 90 cm SID, and the patient exposure is 2.8 mGy. What will the exposure be if the distance is increased to 180 cm and there is no accompanying technique change? | Distance = SQUARE IT! Dealing with Intensity and Distance SQUARED UNDIRECTLY PROPORTIONAL Old/New = New/Old ANSWER: 0.7 mGy |
| MATH: A technologist is using a technique of 100 mA, 500 ms, 60 kVp with a 12:1 grid and need to switch to a 5:1 grid. What is the new mAs that the technologist should use for the exam? | 1. 500 ms converted into secs (1/1000). 3 decimal places to the left = 0.5 seconds so 100 mA X 0.5 secs = 200 mAs 2. Don't touch KVP. Find the grid ratio numbers- 12:1 (6) & 5:1 (2) 3. mAs and Grid are DIRECTLY PROPORTIONAL ANSWER: 20 mAs |
| The inherent filtration in a general purpose radiographic x-ray tube is usually equivalent to: | 1.0 mm Al eq |
| The equivalent added filtration provided by a conventional light-localizing, variable-aperture collimator is closest to: | 1.0 mm Al eq |
| The visible differences between any two selected areas of brightness levels within a displayed radiographic image is known as: | Contrast |
| The primary purpose of adding filtration to an x-ray beam is to: | Remove low-energy x-rays |
| X-rays of higher maximum energy can be obtained by doing which of the following? | Increasing kVp |
| The light-localizing, variable-aperture collimator contributes: | To added filtration |
| Assuming all other technical factors remain the same, if 5 mm Al filtration is added to the x-ray tube: | IR exposure will decrease |
| An x-ray beam can be made harder by increasing which of the following? | Filtration |
| Added filtration: | Protects the patient from unnecessary radiation exposure |
| Wedge filters are: | Used to obtain uniform IR exposure |
| When added filtration is increased: | x-ray quality is enhanced |
| What part of the fluoroscopic image intensifier converts light into electrons? | Photocathode |
| INDIRECT digital imaging with TFT utilizes a scintillator coated with _____________ to convert x-rays into light. | Cesium iodide |
| The global information technology standard which allows modalities to communicate with PACS is: | DICOM |
| The reference histogram of luminance values derived during image acquisition is known as: | LUT |
| The recommended digital exposure index range is 1800-2200. A tech makes an exposure with the technique of 80 kVp at 120 mA and the result EI is 2400? How should the tech adjust the technique for the repeat exposure to be within the recommended EI range? | Cut mA in half. |
| The active layer in a PSP plate is usually made of phosphors from what family group? | Barium fluorohalide |
| The layer of a CR imaging plate that "traps" electrons during exposure is the: | Phosphor layer |
| What is the minification gain for a fluoroscopic image intensifier that has 1" output phosphor and 9" input phosphor? | Minification = input squared / output squared 9^2 / 1^2 = 81/1 = ANSWER: 81 |
| The digital post-processing technique that links multiple images together using specialized software is: | Stitching |
| A decrease in pixel pitch will result in: | Increased spatial resolution |
| Which of the following is not a beam-restricting device? a. A cone b. A PBL device c. A variable-aperture collimator d. Added filtration | d. Added filtration |
| In a light-localizing, variable-aperture collimator: | periodic checks of x-ray beam and light field coincidence are necessary |
| Which of the following devices is normally designated to limit off-focus radiation? | First-stage shutters of a variable-aperture collimator |
| Off-focus radiation results when... | Projectile electrons do not strike the focal spot |
| PBL stands for? | Positive Beam Limitation |
| The principle reason for using a grid is to: | Improve image contrast |
| Which of the following materials would be most radiolucent (more black than white)? | Carbon Fiber |
| Which of the following is the most important grid characteristic? | Grid Ratio |
| In a grid that has lead strips 0.5mm apart and 4 mm high, the grid ratio is: | Grid ratio = h/d. 4/0.5 = 8:1 ANSWER- 8:1 |
| If only scatter radiation reached the image receptor: | Image contrast would be very low |
| In the design of a radiographic grid, which of the following must be true? | The interspace material is radiolucent |
| Grids are principally effective in attenuating which of the following? | X-rays after Compton interaction |
| Which body habitus is the easiest to penetrate? | Asthenic |
| What is the name of the device that converts an analog electronic signal into numeric digital data (binary code)? | Analog-to-digital converter |
| Radiographic grids must be placed between what two things? | Patient and the Image Receptor |
| Which of the following is true about x-ray photons? | They are electrically neutral and have no mass |
| Which of the following techniques will result in the highest patient dose if mAs is changed to maintain IR exposure? | 12:1 parallel grid; 70 kVp |
| Grid cutoff is more pronounced with high-ratio OR low-ratio grids? | High-Ratio grids |
| Air-gap technique results in | Image Magnification |
| Bedside examinations require a wide range of SIDs. Which of the following linear focused grids should a technologist use to reduce the likelihood of grid cutoff to occur? | 5:1 |
| In general, which of the following has the greatest contrast improvement factor? | Crossed grids |
| Which of the following is an undesirable characteristic of linear grids compared with focused grids? | More grid cutoff |
| What is the result of replacing an 8:1 grid with a 12:1 grid? | Higher patient dose |
| The minimum source-to-skin distance of a stationary fluoroscopic x-ray unit is: | 15" (38 cm) |
| Incorrect erasure leaving a previous residual exposure after PSP IP processing is termed: | Ghosting |
| Which of the following are causes of a PSP digital artifacts? | All of the above |
| What is represented on the Y-axis of a histogram? | Number of pixels in each tone |
| MATH: What is the total brightness gain of an image intensifier if the minification gain is 25 and the flux gain is 20? | Total Brightness Gain = Minification Gain X Flux Gain Total Brightness Gain = 25 X 20 ANSWER = 500 |
| Exposure linearity is a quality control test that evaluates: | mA stations |
| Flat field correction is a software to correct the seams of combining CCD's into a larger detector, which is also known as: | Tiling |
| The focusing cup in diagnostic radiography is usually made of: | Nickel |
| The process of thermionic emission occurs in the: | Cathode |
| Which of the following will result in the greatest attenuation of the x-ray beam? | Barium sulfate contrast media |
| The number of pixels per millimeter is referred to as: | Pixel density |
| The average amount of mA used for fluoroscopy is: | 3-5 |
| Electrons traveling from the cathode to the anode travel at what speed? | 1/2 the speed of light |
| The interaction of radiation with matter that results in an increased dose to the patient during general radiography is: | Photoelectric |
| Magnification mode in fluoroscopy will ______________ patient dose. | INCREASE |
| Which of the following is used to convert an analog film into a digital image? | Digitizer |
| The two interactions that occur within the x-ray tube are: | Brems and Characteristic |
| A small bowel obstruction will require __________ to technical factors. | DECREASE Destructive Condition |
| In digital imaging an over exposure will result in __________________. | A loss of contrast |
| The x-ray circuitry device responsible for selecting the kVp is the: | Autotransformer |
| The Nyquist Theorem states that a signal must be sampled at least _______ times the frequency of the input signal. | Two |
| Computers take data from the user and processes it using a machine language of 1s and 0s is known as: | Binary code |
| A CR imaging plate is erased with: | White light |
| To reduce magnification, one should do which of the following? | Reduce OID |
| MATH: If the SID is 100 cm and an object is placed 20 cm from the image receptor, what is the magnification factor (MF)? | MF = SID/SOD; SOD = SID-OID 1. SOD= 100-20 SOD = 80 2. MF = 100/80 MF ANSWER = 1.25 |
| MATH: A 20 cm object is radiographed at 40 cm from the focal spot, and the SID is 60 cm. The size of the image will be: | 1. 60cm SID X 20cm Object / 40 cm ANSWER = 30cm |
| To obtain minimum magnification, one should do which of the following? | Position the anatomy close to the image receptor |
| Which of the following conditions will contribute the least to image distortion? | A thin object at a long SID |
| Which of the following is a photographic property of image quality? a. Contrast b. Distortion c. Elongation d. Spatial Resolution | a. Contrast |
| A foreshortened image results in... | An inclined object |
| Spatial resolution can be increased with the use of what three things? | Longer SID, Small Focal Spot, Shorter OID |
| Magnification factor is not dependent on: | Focal Spot Size |
| What occurs at the step-down transformer in an x-ray circuitry system? | Voltage DECREASES and Amperage INCREASES |
| What occurs at the step-up transformer in an x-ray circuitry system? | Voltage INCREASES and Amperage DECREASES |
| A set of instructions in a computer program that performs a specific function is known as: | algorithms |
| A radiograph that exhibits a long grayscale of contrast includes... | Many shades of gray that have minimal differences |
| In an indirect digital imaging system, the device that converts light into an electronic signal is: | Photodiode |
| What would increase contrast resolution for a cervical spine? | Increase grid ratio |
| A group of networked computers, servers and archives to store digital images is referred to as: | PACS Picture Archiving and Communications System |
| When an examination is changed from an 8:1 grid technique to a non-grid technique, and compensating changes are made in other technique factors: | There will be NO change in IR exposure |
| If a technique of 100 mA, 1000 ms is changed to 200 mA, 500 ms: | There will be NO change in IR exposure |
| Light field to radiation field alignment congruency must be within: | + or - 2 % of the SID |
| The process of assigning a numeric value to each pixel intensity when digitizing an analog image is known as: | Quantization |
| Exposure latitude refers to: | The range of exposures that may be captured by a detector. |
| Saturation of a CCD will cause: | Blackness on an image where gross over exposure has occured. |
Created by:
dominic.zappitelli
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