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technical factors
| Question | Answer |
|---|---|
| 15% rule | A principle used in radiography to maintain image density by adjusting kilovoltage peak (kVp) by 15% to achieve a similar exposure. |
| body habitus | The physical build or body type of a patient, which can affect imaging techniques and radiation exposure. |
| direct square law | A formula used to calculate the necessary adjustments in exposure factors when the distance from the x-ray source to the image receptor changes. |
| exposure maintenance formula | A formula used to maintain consistent exposure to the image receptor despite changes in distance or other factors. |
| inverse-square law | A principle stating that the intensity of radiation is inversely proportional to the square of the distance from the source. |
| magnification factor (MF) | A ratio that describes the enlargement of an image compared to the actual size of the object being imaged. |
| object-to-image-receptor distance (OID) | The distance between the object being imaged and the image receptor, which affects image magnification and resolution. |
| source-to-image-receptor distance (SID) | The distance from the x-ray source to the image receptor, which influences the intensity of radiation and image quality. |
| source-to-object distance (SOD) | The distance from the x-ray source to the object being imaged, which is a factor in determining image magnification. |
| milliamperage (mA) | A measure of the quantity of x-ray photons produced; higher mA results in more radiation and increased image density. |
| exposure time | The duration for which the x-ray beam is active during imaging, affecting the amount of radiation reaching the image receptor. |
| kilovoltage peak (kVp) | The maximum voltage applied across the x-ray tube, influencing both the quality and quantity of the x-ray beam. |
| radiographic image quality | The overall clarity and detail of an image, determined by factors such as brightness, contrast, spatial resolution, distortion, and noise. |
| spatial resolution | The ability of an imaging system to distinguish between small structures and detail within an image. |
| distortion | The misrepresentation of the size or shape of an object in an image, often caused by improper alignment or distance. |
| noise | Unwanted variations in the image that can obscure details and reduce overall image quality. |
| grids | Devices used in radiography to reduce scatter radiation and improve image contrast. |
| beam restriction | The process of limiting the size of the x-ray beam to reduce patient exposure and improve image quality. |
| tube filtration | The use of materials to filter out low-energy x-rays from the beam, enhancing image quality and reducing patient dose. |
| compensating filters | Filters used to even out the exposure across an image by compensating for varying tissue thickness. |
| patient factors | Characteristics of the patient, such as body habitus and thickness, that can influence imaging techniques and radiation exposure. |
| exposure factors | Variables such as mA, exposure time, and kVp that can be adjusted to optimize image quality and minimize patient dose. |
| body habitus considerations | Adjustments made in imaging techniques based on the patient's physical build to ensure optimal image quality. |
| patient thickness considerations | Adjustments in exposure techniques based on the thickness of the patient to maintain image quality and minimize radiation exposure. |
| mAs | Milliamperage-seconds, a product of milliamperage (mA) and exposure time that determines the amount of radiation exposure to the image receptor (IR). |
| Exposure to the IR | The amount of radiation that reaches the image receptor, which increases with higher quantities of x-rays. |
| Quantity of x-rays | The total number of x-rays produced, which can be adjusted by changing the mAs. |
| Inverse proportional relationship | A relationship where an increase in one variable results in a decrease in another, such as mA and exposure time when maintaining the same mAs. |
| Single-phase generators | X-ray generators that produce less radiation compared to high-frequency generators for the same mAs. |
| High-frequency generators | X-ray generators that produce more consistent and higher radiation output compared to single-phase generators. |
| Dynamic range | The range of radiation intensities that a digital image receptor can detect. |
| Quantum noise | Random variations in the image that can occur due to low mAs, resulting in decreased image quality. |
| Histogram automatic rescaling | A computer processing technique that adjusts image brightness when the mAs is too low. |
| Exposure latitude | The range of mAs values that can be used while still producing an acceptable image quality. |
| Radiographic image | An image produced by x-rays that can be affected by the mAs level used during exposure. |
| Brightness in digital images | The level of lightness or darkness in a digital image, which can be adjusted independently of mAs. |
| Radiation exposure | The amount of radiation a patient receives during an x-ray procedure, which should be minimized. |
| Mathematical application of mAs | The calculation of mAs using the formula: mAs = mA x exposure time. |
| Adjusting mA or exposure time | Changing either the milliamperage or the time of exposure to achieve the desired mAs. |
| 200 mA x 0.100 s | An example calculation resulting in 20 mAs. |
| 400 mA x 0.100 s | An example calculation resulting in 40 mAs. |
| 200 mA x 0.200 s | Another example calculation resulting in 40 mAs. |
| High mAs | A condition where the mAs is too high, leading to unnecessary radiation exposure to the patient. |
| Low mAs | A condition where the mAs is too low, potentially resulting in increased quantum noise in the image. |
| Image receptor (IR) | The device that captures the x-ray image, which can vary in sensitivity and response to radiation. |
| Patient factors affecting mAs | Variables such as age, general condition, and thickness of the anatomic part that influence the required mAs for imaging. |
| Brightness alteration | The brightness of a digital image can be altered during image processing. |
| Exposure indicator (EI) | An exposure indicator (EI) is displayed on the processed image to indicate the level of x-ray exposure received on the digital IR. |
| Exposure errors | Exposure errors affect the quality of the digital image and the radiation dose to the patient. |
| kVp | The kVp affects the exposure to the IR because it alters the amount and penetrating ability of the x-ray beam. |
| Subject contrast | The kVp affects subject contrast displayed in the image. |
| Radiographic procedure | Most manufacturers of digital IRS suggest a range for the exposure indicator on the basis of the radiographic procedure. |
| Minimum change in mAs | For repeat images necessitated by exposure errors, the mAs is adjusted by a factor of 2. |
| Diagnostic quality | A radiographic image repeated because of insufficient or excessive exposure requires a change in mAs by a factor of at least 2 to produce an image of diagnostic quality. |
| Monitoring exposure indicator values | The radiographer should be diligent in monitoring exposure indicator values to ensure that quality images are obtained with the lowest reasonable radiation dose to the patient. |
| Low-energy kVp beam | Most x-ray photons are absorbed in a low-energy kVp beam. |
| Image processing | During computer processing, image brightness is maintained when the mAs is too low or too high. |
| Adequate penetration | The area of interest must be adequately penetrated before the mAs can be adjusted to produce a quality radiographic image. |
| Radiation reaching the IR | Increasing the kVp further results in more radiation reaching the IR. |
| Exposure to the digital IR | If the exposure indicator value falls outside the manufacturer's suggested range, exposure to the digital IR could be affected. |
| Image quality | Exposure to the digital IR, image quality, and patient exposure could be affected if the exposure indicator value falls outside the suggested range. |
| Radiographic image repetition | If a radiographic image must be repeated because of another error, the radiographer may use the opportunity to adjust the exposure to the IR. |
| Excessive mAs | An excessive amount of mAs adversely affects image quality and patient radiation exposure. |
| Insufficient mAs | An insufficient amount of mAs adversely affects image quality and patient radiation exposure. |
| X-ray exposure range | Manufacturers specify the expected range of x-ray exposure sufficient to produce a quality image. |
| Low-energy (kVp) beam | A beam where most x-ray photons are absorbed, resulting in few photons emerging to strike the image receptor. |
| High-energy (kVp) beam | A beam where many photons have sufficient energy to penetrate the part being imaged. |
| Exposure to the image receptor (IR) | The amount of radiation that reaches the digital image receptor, influencing image brightness and quality. |
| Diagnostic-quality image | An image produced with appropriate kVp and mAs settings that meets the standards for medical imaging. |
| Exposure indicator value | A numerical representation of the amount of radiation exposure received by the digital image receptor. |
| Radiation protection alert | A warning regarding the risks of excessive radiation exposure to patients during imaging procedures. |
| Computer adjustment | The process by which digital imaging systems modify image brightness to compensate for exposure errors. |
| Overexposure | A condition where excessive radiation is used, leading to increased patient exposure and potential ethical concerns. |
| Underexposure | A condition where insufficient radiation is used, resulting in poor image quality due to increased quantum noise. |
| Mobile x-ray equipment | Portable imaging devices that may limit the choice of mAs settings, requiring adjustments to kVp. |
| Brightness adjustment | The modification of image brightness during processing to achieve a desired visual quality. |
| Increased scatter radiation | Additional radiation that may reach the image receptor, potentially degrading image quality. |
| Ethical practice in radiography | The principle of minimizing patient exposure to radiation while ensuring adequate image quality. |
| Radiographic imaging | The process of creating visual representations of the interior of a body for clinical analysis. |
| Brightness maintenance | The ability of digital systems to keep image brightness consistent despite variations in exposure. |
| Radiation dose | The amount of radiation energy absorbed by the patient during imaging procedures. |
| Increasing exposure to the IR | To increase exposure to the IR, multiply the kVp by 1.15 (original kVp +15%). |
| Decreasing exposure to the IR | To decrease exposure to the IR, multiply the kVp by 0.85 (original kVp - 15%). |
| Maintaining exposure to the IR | When increasing the kVp by 15%, divide the original mAs by 2. |
| Doubling mAs | When decreasing the kVp by 15%, multiply the mAs by 2. |
| Higher kVp effects | Higher kVp increases the beam penetration, requiring less radiation to achieve a desired exposure to the IR. |
| Lower kVp effects | Lower kVp decreases the x-ray beam penetration, resulting in more absorption and less transmission. |
| Penetrating power of x-ray beam | Higher kVp increases the penetrating power of the x-ray beam, resulting in less absorption and more transmission. |
| Compton scattering | An interaction where x-rays scatter off electrons, increasing with higher kVp. |
| Photoelectric absorption | An interaction where x-rays are absorbed by tissues, decreasing with higher kVp. |
| Focal spot size | The physical dimensions of the focal spot on the anode target in x-ray tubes, usually ranging from 0.5 to 1.2 mm. |
| Scatter | Refers to the x-rays that are deflected from their original path, increasing with higher kVp. |
| Radiographic contrast | The difference in density between the light and dark areas of an image, affected by kVp and mAs. |
| Anatomic tissues | The various types of tissues in the body that x-rays interact with, affecting absorption and transmission. |
| X-ray intensities | The amount of x-ray radiation that exits the patient, which varies based on kVp settings. |
| Small focal spot size | Usually 0.5 or 0.6 mm. |
| Large focal spot size | Usually 1 or 1.2 mm. |
| Lower mA settings | Associated with the small filament. |
| Higher mA settings | Energize the large filament. |
| Kilovoltage (kVp) | At higher kVp, more x-rays are transmitted with fewer overall interactions. |
| mAs adjustment | Must be adjusted by a factor of 2 when kVp is changed by 15%. |
| Exposure techniques | Using higher kVp with lower mAs settings is recommended in digital imaging. |
| Computer processing | Controls display contrast primarily during digital imaging. |
| Focal spot size and spatial resolution | As focal spot size increases, unsharpness increases and spatial resolution decreases. |
| Small focal spot usage | Generally, the smallest available focal spot size should be used for every exposure. |
| Heat concentration | When a small focal spot is used, heat is concentrated into a smaller area, which could cause tube damage. |
| Radiation intensity | Varies at different distances due to the divergence of the x-ray beam. |
| Safety circuits in x-ray generators | Prevent exposure if it exceeds the tube-loading capacity for the selected focal spot size. |
| Repeated exposures | Made just under the x-ray tube limit can jeopardize the life of the x-ray tube. |
| Unsharpness | Increases with larger focal spot sizes. |
| Source-to-image receptor distance (SID) | The distance between the x-ray source and the image receptor, which affects the intensity of radiation reaching the IR. |
| Intensity of radiation | The amount of radiation reaching the image receptor, which varies with distance according to the inverse-square law. |
| Direct square law or exposure maintenance formula | A mathematical formula used to adjust the mAs when changing the SID, expressed as mAs₁/mAs₂ = (SID₁)²/(SID₂)². |
| Optimal exposure | The ideal amount of radiation exposure to the image receptor, which can be maintained by adjusting mAs according to SID changes. |
| Size distortion | The magnification or reduction of the size of the object being radiographed, which is affected by the SID. |
| Radiographic quality | The overall clarity and detail of an x-ray image, influenced by factors such as SID and mAs. |
| Mathematical application of inverse-square law | If the intensity of radiation at an SID of 100 cm (40 inches) is equal to 4 mGy (400 mR), the intensity at 180 cm (72 inches) can be calculated using the inverse-square law. |
| Adjustment of mAs for increased SID | When SID is increased, the mAs must be increased to maintain proper exposure to the IR. |
| Adjustment of mAs for decreased SID | When SID is decreased, the mAs must be decreased to maintain proper exposure to the IR. |
| Standard distances in radiography | Commonly used SID values in diagnostic radiography are 100, 120, or 180 cm (40, 48, or 72 inches). |
| Effect of SID on beam intensity | As SID increases, the x-ray beam intensity becomes spread over a larger area, decreasing the overall intensity reaching the IR. |
| Effect of SID on size distortion | As SID increases, size distortion (magnification) decreases. |
| Effect of SID on spatial resolution | As SID increases, spatial resolution increases. |
| Quick method for calculating mAs changes | When adjusting SID, specific rules can be applied, such as using half the mAs when decreasing to 140 cm from 180 cm. |
| Example calculation for mAs adjustment | Optimal exposure at 40 inches (100 cm) using 25 mAs requires an adjustment to 81 mAs at 72 inches (180 cm). |
| Diverging x-rays | X-rays that spread out from the source, affecting the intensity and quality of the image based on SID. |
| Impact of trauma on SID usage | In trauma situations, standard SID may not be used, requiring adjustments in mAs to obtain quality radiographs. |
| Radiographer's role in SID adjustments | The radiographer must determine the necessary changes in mAs when standard SID cannot be used. |
| Standard distances for SID | Used in radiography to accommodate equipment limitations, typically 100 cm (40 inch) or 120 cm (48 inch) SID. |
| 180 cm (72 inch) SID | Used for chest imaging to decrease the magnification of the heart and record its size more accurately. |
| Increasing the SID | Recommended for positions with increased OID, such as lateral and oblique positions, to improve spatial resolution. |
| Effect of OID on beam intensity | A decrease in beam intensity may result as the exit radiation diverges, reducing the overall intensity reaching the IR. |
| mAs compensation | Decreasing exposure to the IR due to increased OID may require an increase in milliampere-seconds (mAs) to compensate. |
| Air gap | Created when sufficient distance exists between the object and IR, reducing scatter radiation from striking the IR. |
| Image contrast | Increased when the amount of scatter radiation reaching the IR is reduced. |
| Percentage of scatter radiation | Determines the amount of OID required to increase image contrast, with more OID needed for areas producing high scatter. |
| Optimal spatial resolution | Achieved when the OID is zero, although this cannot realistically be achieved in radiographic imaging. |
| OID and size distortion relationship | Increasing OID increases magnification and decreases spatial resolution, while decreasing OID has the opposite effect. |
| Radiographer's positioning | The area of interest should be positioned as close to the IR as possible to minimize size distortion. |
| Standardization of OID | The OID necessary to adversely affect image quality has not been standardized. |
| Minimizing OID | Should be done whenever possible, although certain conditions may make this difficult. |
| Increasing SID | Can still reduce size distortion in situations where OID cannot be minimized. |
| True object size | The actual size of the object being radiographed, which cannot be perfectly achieved on an image due to inherent magnification. |
| Percentage of magnification | An expression of how much larger the image size is compared to the true object size, calculated from MF values greater than 1. |
| Example of MF calculation | For an SID of 100 cm and an OID of 7.5 cm, SOD is 92.5 cm, resulting in an MF of 1.081, indicating an image size 8.1% larger than the true object size. |
| Central ray (CR) alignment | The proper direction and positioning of the x-ray beam to minimize distortion and ensure accurate imaging. |
| Shape distortion | Alteration of the shape of the part recorded on the image due to misalignment of the CR, x-ray tube, or image receptor. |
| Right-angle (orthogonal) relationship | An alignment where the IR, part, and CR are at 90 degrees to each other, preferred to minimize shape distortion. |
| Effect of CR angulation | Angling the CR can increase the distance between the source of radiation and the IR, potentially affecting exposure. |
| Anatomy anterior to the posterior surface | Structures that are located in front of the posterior surface of the knee, which may be magnified more due to OID. |
| Proper alignment | Achieving correct positioning among the x-ray tube, part, and IR to produce a quality image with minimal distortion. |
| Improper alignment | Misalignment among the x-ray tube, part, and IR that results in distorted images. |
| Elongation of the olecranon process | A specific type of shape distortion that occurs when the central ray is not perpendicular to the part. |
| Mathematical Application for MF | A calculation method used to determine the magnification factor based on SOD, SID, and OID. |
| Inherent magnification | The unavoidable increase in size of the image compared to the true object size in radiographic imaging. |
| Quality image | An image that has minimal distortion and accurately represents the anatomical structures being examined. |
| Distorted shape | The result of misalignment between the part and the IR, leading to an inaccurate representation of the anatomy. |
| X-ray tube | The device that generates x-rays for imaging by converting electrical energy into radiation. |
| Radiographic grid | A device that is placed between the part of interest and the IR to absorb scatter radiation exiting the patient. |
| Scatter radiation | Radiation that exits the patient and is absorbed by a grid, improving the quality of the displayed image. |
| Displayed image contrast | The quality of the image that is improved by limiting the amount of scatter radiation that reaches the IR. |
| Grid usage criteria | Grids are typically used only when the anatomic part is 10 cm (4 inches) or greater in thickness, and more than 60 kVp is needed for the exam. |
| Grid efficiency | The more efficient a grid is in absorbing scatter, the greater its effect on radiographic contrast. |
| mAs adjustment with grids | Adding, removing, or changing a grid requires an adjustment in mAs to maintain radiation exposure to the IR. |
| Grid conversion formula | A mathematical formula for adjusting the mAs for changes in the type of grid. |
| Grid conversion factor (GCF) | A factor used to multiply or divide the mAs when a grid is added or removed. |
| Grid ratios | The ratios of grids, such as 5:1, 6:1, 8:1, 12:1, and 16:1, which correspond to different grid conversion factors. |
| Grid conversion chart | A table that lists grid ratios and their corresponding grid conversion factors. |
| New mAs calculation | If a quality radiographic image is obtained using 5 mAs at 70 kVp without using a grid, adding a 12:1 grid requires 25 mAs to maintain the same exposure. |
| Exposure conversions | Situations where the radiographer changes several exposure factors simultaneously, such as during mobile imaging or in the operating room. |
| Image quality without grid | A quality image created without a grid. |
| Image quality with grid | An image created with a grid but no adjustment in mAs has higher contrast but increased quantum noise. |
| Proper mAs adjustment | An image created with a grid and appropriate mAs adjustment has higher contrast and less quantum noise. |
| Grid construction and efficiency | Discussed in greater detail in Chapter 8. |
| Adjustment in mAs | The ability to make an adjustment in mAs correctly when changing multiple factors, such as SID, grid, and kVp. |
| Initial Exposure Technique | The original settings used for exposure, including mAs and kVp. |
| New Exposure Technique | The adjusted settings used for exposure after changes have been made. |
| Decrease from 80 to 68 kVp | A 15% decrease calculated as (80 × 0.85). |
| Increase mAs | Doubling the mAs value, calculated as 25 x 2 = 50 mAs. |
| New mAs for similar exposure | The new mAs needed to maintain a similar exposure to the IR as the initial technique. |
| SID | Source-to-Image Distance, the distance from the x-ray tube to the image receptor. |
| Effect of larger field size | Increases the amount of tissue irradiated and scatter radiation produced, resulting in less radiographic contrast. |
| Effect of smaller field size | Reduces the amount of tissue irradiated and scatter radiation produced, resulting in higher radiographic contrast. |
| Collimation | The process of limiting the x-ray field size to just beyond the area of interest. |
| Generator output | The efficiency of radiation output depending on the type of generator used. |
| Single-phase generator | A type of generator that requires more mAs compared to three-phase generators for similar imaging. |
| Three-phase generator | A more efficient type of generator that requires lower exposure technique settings. |
| High-frequency generator | A generator that provides increased quantity and quality of x-ray production. |
| Calibration of x-ray generators | The periodic process to ensure consistent radiation output from x-ray equipment. |
| X-ray energy (keV) | The energy level of x-rays, which is affected by the type of generator used. |
| Tissue irradiated | The amount of biological tissue exposed to radiation during an x-ray procedure. |
| Excessive filtration | X-ray tubes with excessive filtration may affect image quality. |
| Insufficient filtration | Insufficient tube filtration increases the quantity of radiation and decreases the ratio of higher-penetrating x-rays to lower-penetrating x-rays. |
| Average energy of the x-ray beam | Increasing the amount of tube filtration increases the average energy of the x-ray beam. |
| Digital IRS preference | With digital IRS, an x-ray beam with a higher average energy is preferred. |
| Copper as filter material | Copper (Z# 29) is being employed as a filter material in combination with aluminum. |
| Entrance skin exposure (ESE) | The addition of copper reduces entrance skin exposure (ESE) with no visible loss in contrast resolution. |
| mAs increase with compensating filters | The use of compensating filters requires an increase in the mAs to maintain the overall exposure to the IR. |
| Types of body habitus | There are generally four types of body habitus: sthenic, hyposthenic, hypersthenic, and asthenic. |
| Sthenic body habitus | The sthenic body habitus is commonly called a normal or average build. |
| Hyposthenic body habitus | The hyposthenic type refers to a more slender and taller build. |
| Hypersthenic body habitus | The hypersthenic body habitus refers to a large, stocky build. |
| Asthenic body habitus | Asthenic body habitus is characterized by a slender and tall build. |
| Radiation quantity | Increasing tube filtration decreases radiation quantity. |
| Radiation quality | Increasing tube filtration increases the average energy of the x-ray beam. |
| Asthenic | Refers to a very slender body habitus, with exposure factors at the low end of technique charts. |
| Sthenic | Individuals with average body habitus, having moderate exposure factors for radiographic examinations. |
| Hyposthenic | Individuals with a body habitus that is between sthenic and asthenic, with moderate exposure factors. |
| Part thickness | The thickness of the anatomic part being imaged, affecting x-ray beam attenuation. |
| X-ray beam attenuation | The reduction in the intensity of the x-ray beam as it passes through matter. |
| Exponential attenuation | The principle that x-rays are reduced by approximately 50% for each 4 to 5 cm (1.6-2 inches) of tissue thickness. |
| Effective atomic number | A measure of how much radiation a tissue can absorb, affecting radiographic image quality. |
| Tissue density | The compactness of tissue, influencing its absorption characteristics in radiography. |
| Scattered radiation | Radiation that is deflected from its original path, increasing with tissue thickness. |
| Brightness levels | The varying degrees of lightness or darkness in a radiographic image, determined by tissue absorption. |
| High subject contrast | Results from great differences in radiation absorption between tissues that vary greatly in composition. |
| Low subject contrast | Occurs when anatomic structures consist of a similar type of tissue, resulting in minimal differences in absorption. |
| Tissue composition | The makeup of anatomic structures, affecting their absorption characteristics and the resulting image contrast. |
| Diagnostic image | An image obtained for the purpose of diagnosing a medical condition. |
| Image adjustment | Modifications made to exposure settings to achieve optimal image quality. |
| Radiographer | A professional trained to perform radiographic examinations and produce diagnostic images. |
| Lower subject contrast | Resulting from fewer differences in radiation absorption between tissues that are more similarly composed. |
| Contrast resolution | The ability of a radiologist to inspect the contrast between fat and water-based connective tissues such as muscle and fascia. |
| Fat stripes and pads | Anatomical collections of fat that are important for interpretation as they indicate underlying pathologies. |
| Tissue effusion | Fluid collection indicating underlying pathologies. |
| Soft tissue injury | Injury to the soft tissues that may be indicated by fat/water contrast. |
| Fractures | Breaks in bone that may be indicated by the visualization of fat and connective tissues. |
| Effective atomic numbers | Low values for fat and connective tissues that result in subtle contrast between them. |
| Photoelectric interactions | Interactions that occur to create tissue contrast, particularly important at lower kVp values. |
| Anatomic details visibility | Can be compromised if the kVp is too low to penetrate the anatomic area. |
| Best practice for imaging | Routine use of a higher kVp and lower mAs within the recommended exposure latitude. |
| Patient thickness | Every 4- to 5-cm change in thickness changes mAs by a factor of 2. |
| OID | Object-to-image-receptor distance. |
| SOD | Source-to-object distance. |
| High kVp for chest imaging | Required (>100 when using a grid) to best visualize the range of tissue opacities in the chest cavity. |
| High kVp | Produces an image with a wider range of gray shades and lower subject contrast, best for visualizing both radiopaque and radiolucent tissues. |
| Lower-contrast image | Produces more shades of gray and fewer differences among them, providing better visualization of anatomic tissues that vary greatly in differential absorption. |
| Quality of a radiographic image | Depends on a multitude of variables, and knowledge of these variables assists the radiographer in producing quality radiographs. |
| kVp: 15% rule | Increasing kVp by 15% requires halving the mAs to maintain exposure to the image receptor. |
| CR Angle | Increasing CR Angle decreases quantity, while decreasing CR Angle increases quantity. |
| Grid | Increasing grid ratio has no effect, while decreasing grid ratio increases quantity and scatter. |
| Compensating Filter | Adding a compensating filter decreases quantity, while increasing part thickness decreases quantity. |
| Excessive Tube Filtration | Decreases quantity and has no effect on quality. |
| Insufficient Tube Filtration | Increases quantity and has no effect on quality. |
| Central Ray Angle | Increasing central ray angle decreases quantity and can cause shape distortion. |
| Grid Use | Adding a grid increases quantity and average energy. |
| IR Exposure | The quantity of x-rays produced and exposure to the image receptor (IR) is directly proportional to the product of mA and exposure time (mAs). |
| Exposure Indicator | A numerical value displayed on the processed digital image indicating the level of x-ray exposure received on the IR. |
| Inverse Relationship | The mA and exposure time have an inverse relationship to maintain exposure to the IR. |
| Exposure Factor Change | Recommended to maintain radiation exposure to the IR when increasing patient thickness by 5 cm is to double the mAs. |
| Contrast Adjustment | Brightness and contrast can be adjusted by the computer; increase is higher contrast, and decrease is lower contrast. |
| Direct Proportional | Refers to the relationship between mA and exposure time to maintain exposure to the IR. |
| Inverse Proportional | Refers to the relationship between SID and radiation intensity reaching the patient and IR. |
| Magnification | Increasing OID increases magnification. |
| Exposure Technique Compensation | Necessary to maintain image quality when factors like OID or SID are altered. |
| Quality Control | Maintaining consistent exposure techniques is essential for producing quality diagnostic images. |
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