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121 Imaging Unit 1
| Question | Answer |
|---|---|
| Density is a _____ Photographic property. | Quantitative |
| Density defines the ______ of the image. | Completeness |
| Density & Contrast control the _____ of details | Visibility |
| Proper _____ is required to correctly evaluate contrast, recorded detail or distortion | Density |
| Factors that Influence & Control Density are: 2 things | 1) Pt. Thickness & Opacity 2) Prime Factors |
| What are the 4 prime factors? | 1) mA 2) Time 3) kVp 4) Distance (SID) |
| Things that determine Pt. thickness & Opacity | 1) Physique (habitus) 2) Age/Sex 3) Development 4) Pathology/Trauma 5) Tissue composition/Density 6) Ratio of Soft tissue/bone or Fat/muscle 7) Hollow vs. solid organs 8) Presence or absence of contrast 9) Presence or absence of cast |
| Post reduction wet cast technique (2) | 1) 2x mAs + 10% kVp 2) +15kVp |
| Post reduction dry cast technique | 1) 2x mAs 2) 15 kVp |
| ____, ______, ______, & ______ are main factors that influence how much radiation will be absorbed by a body part | 1) Thickness 2) Atomic number 3) Atomic Density 4) kilovoltage |
| __-___cm thickness of normal tissue will absorbe ____% of a typical beam of xrays | 1) 4-5 2) 50% |
| # of Electrons moving from cathode to anode per second is the _____ _____ and is measured in ____ | 1) Tube current 2) mA |
| mA controls the _________ of the x-ray beam | Exposure Rate |
| Radiographic density is ______ proportional to mA if time is constant. | Directly |
| ______ _______ is the duration that the tbe current is allowed to flow. | Exposure Time (time) |
| ____ does not control or influence the exposure rate, but rather how long the exposure is permitted to continue | Time |
| mAs is the ______ of mA & _____. | 1) Product 2) Time |
| Radiographic density is _____ proportional to mAs | Directly |
| mA & Time are ______ proportional if all other factors are constant | Inversely |
| ______% change in mAs is needed to have a visible change | 30% |
| To correct moderate overexposure you should ______ mAs by _______ | 1) reduce 2) one half |
| To Correct moderate underexposure you should ______ mAs by ______ | 1) increase 2) Double |
| ______ or a slight enlarging of the focal spot. | Blooming |
| Blooming or slight enlargment of the focal spot occurs with ______ ______ of mA. The F.S. tends to decrease slightly when kVP is ______ | 1) large increases 2) Increased |
| Changing mAs does not influence the penetration ability of the xray beam? True or False | True |
| mAs influences the number of _____ produced | xray photons |
| _____ is the electric potential difference (electrical pressure) applied b/t the cathode & anode in the xray tube and serves to drive the electrons from the filament on the cathode to the target on the anode | kVp |
| As kV is increased the energy of the photons ______ and the beam is ___ penetrating | 1) increase 2) more |
| 1) kV increase will increase the _____ & ______ of the beam and _____ the wavelength. | 1) Energy 2) Penetration 3) Decrease |
| With all other factors the same, increasing kV will _____ exposure rate | increase |
| kV is the controlling factor of _______. | Contrast |
| Increasing kV _______ contrast | decreases |
| kVp is a secondary controlling or influencing factor for ______ | Density |
| kVp has a ______ relationship b/t it and exposure but it is not proportional. | Direct |
| There is no precise method for determining kVp-mAs density ratio. True or False | True |
| Law of Reciprocity | mA * T = mAs |
| Sharpness of Detail has 2 subcategories | 1) Recorded Detail 2) Distortion |
| Recorded Detail has 3 factors | 1) Geometric Factor 2) Motion Factor 3) Material Factors |
| Geometric Factors are (3) | 1) Focal Spot size 2) SID 3) OID |
| Material factors are (2) | 1) Film/Screen combination 2) Film/Screen contact |
| Distortion has 2 Factors | 1) Size distortion 2) Shape Distortion |
| Size distortions are (2) | 1) SID 2) OID |
| Shape Distortion is | Tube-part-film alignment |
| Visibility of detail has 2 subcategories | 1) Density 2) Contrast |
| Density factors (9) | 1) mAs 2) kVp 3) SID 4) Collimation 5) Grid Ratio 6) Filtration 7) Pathology 8) Anatomy 9) Film/Screen Combination |
| Contrast Factors (7) | 1) kVp 2) Collimation 3) Grid Ratio 4) Filtration 5) Pathology 6) Anatomy 7) Film/Screen Combination |
| Gray Scale What shows up in each 1) Black= ______ (1) 2) Dark Gray= ______(1) 3) Medium Gray= _______(1) 4) Light Gray=______(2) 5) Lighter Gray= _____(3) 6) White=_____(2) | 1) Air 2) Nothing 3) Fat 4) Fluid/Water 5) Muscle, Blood, Solid Organs 6) Bone, Contrast Media |
| Grid Factors 1) NO Grid = _____ 2) 5:1=____ 3) 6:1=____ 4) 8:1=____ 5) 10:1 & 12:1=____ 6) 15:1 & 16:1=____ | 1) 1 2) 2 3) 3 4) 4 5) 5 6) 6 |
| Black areas are called _____ and white areas are called _____ | 1) Opaque 2) Translucent |
| Black areas on the film have received less radiation exposure. True or False | False |
| White areas received less radiation exposure. True or False | True |
| What are the 4 Radiograpic Properties | 1) Density 2) Contrast 3) Recorded Detail 4) Distortion |
| _______ measures light transmitted through Film | Dencstometer |
| _______ measures the amount of Ionization in air | Dosimeter |
| _____ _____ _____ are on the film and react with xray Photons afterward they become ____ ____ ____ which shows up black on xray film | 1) Silver Halide Crystals 2) Black Metallic Silver |
| The formation of silver halide crystals to black metallic silver is called the what | Gurney-Mott Theory |
| Density is useful as a diagnostic tool when it falls within this range. | .25+b+f - 2.0+b+f |
| Smallest bundle/packet of energy that travels in wave form but is not visible | Photon |
| Exposure Rate is also known as _____ | Time |
| Ionization in Air is measured in | Roentgen |
| 2*mA = 2*#Electrons = 2*#x-rays = 2*Density True or false | True |
| ______ is the adding or removing of electrons from an atom | Ionization |
| mAs is the ______ controller of x-ray _____ & ______ | 1) Primary 2) Quantity 3) Density |
| xray quantity & radiographic density are indirectly proportional to mAs True or False | False |
| Short wavelength has ____ penetration and is caused by ____ kVp | 1) High 2) High |
| Long wavelength has ____ penetration and is caused by ___ kVp | 1) low 2) Low |
| ___ has the greatest effect on density compared to mA, Time & SID | kVp |
| Doubling the kVp will cause density to increase by a factor of 4, 5, or 6 True or False | True |
| Changes in kVp can be visible as low as ___% | 5% |
| To increase kVp by 15% is like doubling the mAs and decreasing kVp by 15% is like halving the mAs this is called the what | 15% Rule |
| kV and contrast are _____ proportional | inversely |
| to decrease contrast and maintain density you would do what | Increase kVp by 15% & 1/2 mAs |
| to increase contrast and maintain density you would do what | Decrease kVp by 15% & Double mAs |
Created by:
Ravann
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