Help
Options
Question
What are the factors that affect recorded detail (Resolution)?
click to flip
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't know
Question
Term referring to misrepresentation of the actual size or shape of the structures imaged
Remaining cards (89)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
RADT456 Img Acq & Ev
ARRT registry review covering Image Acquisition and Evaluation
| Question | Answer |
|---|---|
| What are the factors that affect recorded detail (Resolution)? | OID, SID, Focal Spot Size, Patient factors, intensifying screens, and motion (pg. 298) |
| Term referring to misrepresentation of the actual size or shape of the structures imaged | Distortion (pg. 299) |
| Term that describes how closely fine details may be associated and still be recognized as separate details. | Resolution (pg. 299) |
| Term that refers to how well recorded detail can be seen | Visibility (pg. 299) |
| Two types of shape distortion | Foreshortening and Elongation (pg. 299) |
| Best method of minimizing voluntary motion | Good communication and suspended respiration (pg. 309) |
| Best method of minimizing involuntary motion | Short exposure time (pg. 309) |
| Intensifying screen speed increases as... | phosphor size increases, active/phosphor layer thickness increases, phosphor sensitivity increases, screen reflectance increases, recorded detail decreases (pg. 312) |
| Phosphors with a _____ atomic number react to x-ray photons more efficiently and possess greater speed. | High (pg. 312) |
| Defined as the overall amount of blackening on a radiographic image | Density (pg. 314) |
| Law that states "any combination of mA and exposure time that will produce a particular mAs, will produce identical image density." | Reciprocity Law (pg. 317) |
| The single most important factor associated with image density | mAs (pg. 317) |
| Minimum change in mAs to notice a recognizable change in density | 30% (pg. 317) |
| Equation for inverse square law | I1/I2 = D2^2/D1^2 (pg. 319) |
| Density maintenance formula | mAs1/mAs2 = D1^2/D2^2 (pg. 319) |
| Screen speed and image density are ________ proportional. | Directly (pg. 321) |
| Device used to absorb unwanted scatter radiation before it reaches the IR | Grid (pg. 323) |
| Grids are recommended for body parts ________ | 10 cm and greater (pg. 323) |
| Contributing factors to scatter radiation production | Larger x-ray field size (reduce by collimating), higher kV (correct by using optimum kVp), and thicker/denser body tissues (correct by using compression) (pg. 324) |
| Unwanted absorption of the useful x-ray beam with resulting loss of density across the image | Grid cutoff (pg. 324) |
| Types of grid use errors that contribute to grid cutoff. | Angling against grid lines, off level errors, off-focus errors, off center errors, and upside-down grid. (pg. 325) |
| Height of the lead strips in a grid compared with the distance between them | Grid ratio (pg. 326) |
| Number of lead strips per inch in a grid is termed as | Grid frequency (pg. 326) |
| Material for interspaces within a grid | Plastic, fiber, or aluminum (pg. 327) |
| Grid conversion factors | No grid - 1 5:1 grid - 2 6:1 grid - 3 8:1 grid - 4 10:1 or 12:1 - 5 16:1 - 6 (pg. 327) |
| Air gap technique of 6 inches provides similar results to a _______ grid, while a 10 inch air gap produces an effect that is equivalent to a _______ grid.. | 8:1, 16:1 (pg. 329) |
| How much filtration is required for radiographic tubes operated above 70 kVp? | 2.5 mm Al equivalent (pg. 330) |
| Purpose of filtration | To remove diagnostically useless x-ray photons that contribute only to patient dose (increases overall average energy of x-ray beam) (pg. 330) |
| Formula for total filtration | Inherent x added = total filtration (pg. 330) |
| Compensating filters are used for... | anatomic parts with very different thickness/absorption properties, and to balance the differences in these densities. (pg. 330) |
| Pathologic conditions that would require an increase in technique to produce a diagnostic image. | Ascites, rheumatoid arthritis, Paget disease, pneumonia, atelectasis, congestive heart failure, and edematous tissue (pg. 333) |
| Pathologic conditions that would require a decrease in technique to produce a diagnostic image. | Osteoporosis, osteomalacia, pneumoperitoneum, emphysema, degenerative arthritis, atrophic and necrotic conditions (pg. 333) |
| True or False: Beam restriction (collimation) reduces production of scattered radiation and, consequently, decreases image density. | True (pg. 336) |
| To use the anode-heel effect properly, the larger/thicker body part needs to be positioned on the ________ side. | Cathode (pg. 336) |
| True or False: In traditional (chemical) film processing, even small temperature changes of 2-3 degrees can cause a significant change in image density. | True (pg. 336) |
| When an image only contains a few number of densities, the image is considered to be of what scale? | Short scale or high contrast (pg. 339) |
| When there are many shades of densities with only slight differences between them on an image, this image is said to be... | Long scale or low contrast (pg. 339) |
| Subject contrast is a result of ________ ________. | Differential absorption (pg. 339) |
| What type of image contrast does low kVp create? | High contrast/short scale contrast (pg. 340) |
| What type of image contrast does high kVp create? | Low or long scale contrast (pg. 340) |
| Function of the contrast scale | Make image details visible (pg. 340) |
| Factors used to control the production of scattered radiation and improve contrast | Collimation, Optimum kVp, and thickness/density of tissues (compression). (pg. 344) |
| Without the use of a grid, scattered radiation can contribute to ___________ of the total image exposure. | 50-90% (pg. 347) |
| As grid ratio increases..... | Scattered radiation cleanup increases and contrast improves, contrast scale decreases (higher contrast results), exposure factors must increase, patient dose increases, and positioning latitude decreases. (pg. 347) |
| Two types of AECs | Ionization chamber and phototimer. (pg. 350) |
| Proper functioning of AEC is dependent upon... | Accurate positioning of body part of interest over selected photocell(s). (pg. 352) |
| True or false: Digital imaging has better spatial resolution than traditional film based imaging. | False. Film based imaging has an approximate spatial resolution of 10 lp/mm, while CR/DR ranges between 2.5 and 5 lp/mm. (pg. 354) |
| Related to the number of shades of gray within an image and is measured in bits | Dynamic range (pg. 355) |
| As matrix size increases (for a fixed field of view), pixel size is _______ and image resolution _______. | Smaller, increases (pg. 355) |
| Described as how much of the patient is included in the image matrix. | Field Of View (FOV). (pg. 356) |
| Type of signal to noise ratio that is desired for a diagnostic image. | High SNR (pg. 356) |
| Ability of an image receptor material to perceive and interact with x-ray photons. | Detective Quantum Efficiency (DQE). (pg. 356) |
| Materials used for CR/DR PSP receptor screens | cesium iodide, barium fluorohalide, and amorphous selenium. (pg. 356) |
| List the layers of a PSP in order | Protective layer, needle-shaped phosphor layer, reflective backing, polyester base support, antistatic layer, and lead foil backing (pg. 358) |
| The latent image can remain on a PSP for up to ______ hours before image fading is noticeable. | Eight (pg. 359) |
| If an IP and its storage plate has been unused for _________ hours, the PSP plate should be erased before use. | 48. (pg. 359) |
| Which step does a direct capture DR system eliminate in image production? | Scintillator step (pg. 364) |
| Smaller detector element size within a thin film transistor, the ________ the spatial resolution. | Better (pg. 364) |
| A computer system that serves to track patient information (Admission/discharge, diagnostic treatment services, pharmaceutical and equipment information/ billing information, and employee information. | Hospital Information System (HIS). (pg. 366) |
| Computer system that allows procedure ordering/scheduling, patient database maintenance, reporting and transcription, and billing within the radiology department. | Radiology Information System (RIS). (pg. 366) |
| The most common result of improper film storage. | Fog (pg. 381) |
| Unexposed film should be stored below what temperature? | Below 70 degrees F. (pg. 381) |
| Atmospheric humidity for film storage should be ... | between 40 and 60%. (pg. 381) |
| Tool/test used to test screen-film contact. | Wire mesh test (pg. 383) |
| Three classifications for image artifacts. | Handling, Processing, and Exposure. (pg. 383) |
| Information required on each x-ray image in order to be considered as legitimate legal evidence. | Patient name/identification number, side marker (right or left), examination date, and institution's name. (pg. 384) |
| Type of grain or crystal suspended within gelatin of film emulsion. | Silver bromide (halide) crystals. (pg. 385) |
| Purpose of developer solution in chemical film processing. | Converts latent image into the manifest silver image by reducing the exposed silver bromide grains to black metallic silver. (pg. 385) |
| Purpose of activator solution in chemical film processing. | Swells gelatin emulsion, enabling the reducing agents to penetrate the emulsion and reach the exposed silver bromide grains. (pg. 385) |
| Purpose of preservative solution in chemical film processing. | Prevents rapid oxidation to developer. (pg. 385) |
| Purpose of restrainer solution in chemical film processing. | Restricts developer activity to only react with exposed silver grains (controls fog). (pg. 386) |
| Purpose of fixer solution in chemical film processing. | Clears the film of unexposed, undeveloped silver bromide grains. (pg. 386) |
| Purpose of the "wash" process within chemical film processing. | Clears film of residual chemicals and is important for archival quality. (pg. 386) |
| Purpose of the hardener solution in chemical film processing. | Re-hardens gelatin emulsion to protect film from abrasions. (pg. 386) |
| Racks within a processor that are out of solution and bridge the gaps between the sections of the transport system. | Crossover racks. (pg. 387) |
| Located at the bottom of deep racks and serve to change the film direction as it changes from downward to upward motion. | Turnaround Racks. (pg. 387) |
| Temperature range that is maintained within a chemical processor. | 92-95 degrees farenheit (pg. 387) |
| Two methods of silver recovery. | Metallic displacement cartridges and electrolytic silver recovery. (pg. 388 & 389) |
| Three cycles a PSP undergoes | X-ray exposure, reading, and erasure. (Pg. 393) |
| A graphic representation of pixel value distribution | Histogram (Pg. 394) |
| Factors that affect a historgram analysis | Positioning accuracy, correct collimation, correct algorithm, delay in processing, changes in scatter radiation, SID, and OID. (Pg. 395) |
| A change in window width changes... | the number of gray shades (Pg. 396) |
| A change in the window level changes... | image brightness (Pg. 396) |
| The acronym PACS stands for... | Picture Archiving and Communications System (Pg. 396) |
| Factors that can create distortion | Patient motion, excessive OID, insufficient SID, inappropriate screen/film combination, too large of focal spot. (Pg. 405) |
| Shape distortion is a result of ... | improper alignment of x-ray tube, body part, and image receptor (Pg. 405) |
| Uses for slower screen speeds (i.e. 100) | Small parts such as extremities (Pg. 407) |
| PSPs are sensitive to... | electromagnetic radiations such as ultra-violet and gamma, as well as particulate radiations such as alpha and beta particles. (Pg. 408) |
| Greatest enemy to image detail. | Patient motion (Pg. 413) |
| Solution that is recommended for cleaning PSPs. | Anhydrous ethanol (other materials can cause breakdown of the protective coat and create artifacts). (Pg. 423) |
Created by:
jksmith1
Popular Radiology sets