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Radiographic Density
Ch 28
| Question | Answer |
|---|---|
| _______ is the degree of overall blackening of the film. (photographic property that comprise visibility of detail) | Density |
| ______ is the concept of density as it is displayed on a soft-copy monitor for digital images. | brightness |
| ________ describes the digital processing that produces changes in density/brightness. | Window level |
| What range of OD is visible to the human eye? | OD 0.25-2.50 |
| What is the major consideration in assessing density verification? | That proper densities are visible throughout the anatomical area of interest on the image. |
| The ____ image has received too many photons and has recorded too much information. | overexposed |
| If any image is overexposed, the ________can be adjusted to fix the density of the image. | window level |
| Whenever a choice must be made between excess and insufficient density, the best decision is always the choice that will produce the ________ image. | overexposed |
| If exposure conditions push into the toe or shoulder regions of the curve, dramatic _____________ changes can be seen. | film density |
| _______ is the controlling factor of density. | mAs |
| ______ is the influencing factor of density | kVp |
| mAs should be used as a principle method for adjusting for _______ or _______ density. | insufficient/excessive |
| _______is determined by the characteristics of the IR. | density |
| _______ is the ability of the film to stop light. | Opacity |
| If a region of a radiograph has an OD of 1.0 only _______ of the incident light is transmitted through the radiograph in that region. | 10% or 1/10 |
| The straight line portion of the D lo E curve, film density is _________ to the log relative exposure. | approximately proportional |
| Will doubling the exposure result in a doubling the film density? | NO |
| Image density/brightness on the display monitor is controlled by ___________. | window leveling |
| Setting the correct ____ is still critical in determining the proper digital image receptor exposure. | mAs |
| Digital image histograms are ____________ of the exposure to the IR. | graphic representations |
| As mAs increases, ________ increases proportionally and ________ also increases. | exposure/film density |
| The reciprocity law fails for __________ or _________ exposure times. | extremely short or long |
| If the mAs used to create one image is the same as the mAs used to create a second image of the same structure, then both images should have the same __________. | film density |
| The minimum change necessary to cause a visible shift in film density is ______ of mAs or any other influencing factors that would equal this change. | 30% |
| _______ is mainly controlled by the radiographer, but can also be preset with a computerized exposure system. | mAs |
| A _______ or _________ can eliminate the excess information and reveal details within the range of human visual ability. | bright light/scanner |
| The general rule of thumb for mAs changes is to make adjustments in increments of ______ or ______. | doubles/halves |
| Kilovoltage has a __________ effect on density. | profound |
| Kilovoltage contols the average ____ of the x-ray photon produced at the anode target. | energy |
| The 15% rule is used as a guide to maintain the same image receptor exposure film density when _______ changes. | kilovoltage |
| The 15% rule will always change the ______ of the image. | contrast |
| A radiograph of the elbow is produced using 4 mAs at 60 kVp. What kVp would be required to halve the exposure to the IR. | 51 kVp |
| The 15% rule may vary from a 15% rule to a _____% rule. | 25 |
| Motion has what impact on density? | none |
| What is grid ratio? | 16:1 and 8:1; amount of lead strips in a grid |
| An increase in pt size will ______ density and a decrease in pt size will _____ density. | decrease; increase |
| Increase in field size will ____ density. | increase |
| An increase lead in the grid will ____ density. | decrease |
| An increase in screen speed will ____ density.(more efficient) | increase |
| What kind of relationship is distance to density? | an inverse relationship (inverse square law) |
| A decrease in OID will result in an increase in density: this is an example of a _______. | inverse relationship |
| Increased generator will result in an ______ density. (high field, more efficient) | increase |
| A radiograph of the chest with pneumothorax will result in a a radiograph with more ______. | density |
| Pulmonary edema would show on a radiograph with ______ density. | Less |
| The two photographic factors that allow detail to be seen are ______ and ______. | density/contrast |
| As developer solution temperature increases, film density will _______. | increase |
| If a satisfactory exposure is obtained with 20 mAs at 72", what mAs will be required to maintain the same exposure at 40"? | 6.2 mAs |
| If a satisfactory PA chest radiograph is made at 72" with 4 mAs, what mAs, will be required at 56"? | 2.5 mAs |
| A radiograph of the elbow is produced using a 4 mAs at 60 kVp. What kVp would be required to halve the exposure to the IR? | 51 kVp |
| ___________ affects kVp's affect on density. | generator efficiency |
| Thicker anatomical parts should be placed on the _____ side and smaller anatomical parts should be placed on the _____ side. | cathode/anode |
| ______ charged electrons cause a blooming effect. | negatively |
| If a radiograph using 40 mAs (400mA at 0.10 sec.) produced a radiograph with satisfactory density, what new time should be used at 200 mA? | 40 mAs/200mA = .20 sec |
| A radiograph of the forearm is produced using 4 mAs at 55kVp. What kVp would be required to double the exposure? | 63 kVp (55 kVp + 8.25 kVp =63 kVp (63.25 kVp.) |
| An x-ray exposure of 240 mR is recorded at a distance of 20 inches. If the same technical factors are used, what will the exposure be if the distance is increased to 40 inches? | mAs2=60 |
| If a satisfactory density is obtained with 40 mAs at 72 in., what mAs is required to maintain the same density at 40 in.? | mAs2=12 |
| What is the proper mAs for use with an 80 RS system when technical factors of 55 kVp and 5 mAs produce an acceptable image with a 200 RS system? | 12.5 mAs |
| An increase in patient size will ___________ density. A decrease in patient size will _______ density. | decrease; increase |
| An increase in beam restriction will ________ density. | decrease |
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