click below
click below
Normal Size Small Size show me how
Limited Rad Cht 8
Question | Answer |
---|---|
What should a radiograph image have? | Density, Constrast, Good recorded detail |
What are the properties of an Image? | Density, Contrast |
What are the photographic properties of an Image? | Recorded Detail, Distortion, Magnification |
What techniques are responsible for a radiographic Image? | mAs, Time, KVP, SID |
What can influence the production of an image? | Tube Aligment, OFD, Thickness of tissue, Collimation, Beam Filters, Fog |
What are major for a radiographic Image? | Density & Constrast |
What is Density? | The Blackness of an image |
What controls Density? | mAs |
What can be proportional to Density? | Amt of mA used for exposure |
As more production in tube + More radiation? | More Bk density in the film |
Density is directly proportional to? | mA & Time |
If mA 2x? | Qty 2x |
What can affect film darkening? | mA & mAs |
What is mAs? | mA x Time = mAs |
What are the 4 rules of mAs? | mAs = Qty of radiationmAs = Qty of dosage2X Time + 2X mAs = Same effect (has)mA x Time is constant (same) |
What is the Reciprocity Law? | Used to determine Density Any combination of mA x Time that = same amount of Density |
What is best for Reciprocity Law? | Always go for fast time & avoid motion |
What can control mAs? | Focal Size Spot Time |
What controls a recorded detail? | Focal Spot |
What size of Focal is best for a good image? | SFS: Sharp Image, Good Anatomy |
A disadvantage for a SFS? | Can't tolerate heat w/long time |
What can change a direct effect on Density? | KVP, SID, Heel Effect, Film Processing, Fog |
What does KVP control? | Contrast & Density |
2 ways that KVP affect Density | ^ KVP = ^ penetration^ KVP = ++ radiation energy |
KVP ^ + ^ radiation energy = ? | more scatter, ^ Density |
What is The Inverse2 Law? | The Intensity of radiation has a relationship w/ the sq2 of the distance |
What is the Inverse2 Law used for? | Density, Radiation Intensity, Rad Dosage |
Summary of the Inverse2 Law | SID ^ 4X greaterA relationship w/ SIDA new mAs |
What is required for a change in SID? | New mAs to get some amt of Density on r. graph |
What is Heel Effect? | The tube's target (anode) |
What is film fog? | unwanted density |
What is the cause of film fog? | Old Film, light, scatter |
What are artifacts? | Foreign marks in film |
Artifacts can effect the ^ v of? | Density |
3 Types of contrast? | Radiographic, subject, film |
What is radiographic contrast? | Bk-silver in film (controlled by KVP) |
Contrast can? | Enhance info |
A blacker image has? | Less radiation |
A whitere image has? | More radiation |
Which image will have more Density? | An image that is whiter |
Radiation of a ^ energy? | Has short waves, produces a long scale |
What is short scale? | Image w/ gray scales |
What is long scale? | Image w/ bk-wht scales |
What influences a rad image? | Subject contrast & film contrast |
What is subject contrast? | Diff between skin @ bones of anatomical part |
Aerial Image? | Radiation enters- exits the body |
Film Contrast? | Type of Film |
What can screens do? | Converts rad energy to visible light, ^ contrast |
15% rule? | #KVP x +0.15% #KVP x - 0.15% |
What is the purpose of 15% rule? | 2X KVP penetration v contrast |
By v 15% rule in KVP | v mAs by 1/2 |
Image underexposed? | Lacks density, Add mAs |
Underexposed, can you add more KVP? | No, will add more scatter |
What 2 factors are used for film contrast? | mAs(density) + KVP (contrast) to be complimentary |
mAs & contrast? | Controls radiation, KVP controls constant |
Too much mAs? | ^ Density |
A change in distance? | Change in scatter |
Will distance affect constrast? | No change |
What influences Density & Constrast? | Beam restriction, Beam filtration, Skin compression |
Beam restriction? | v scatter |
Beam filtration? | Gets rid of v energy |
Skin compression? | v contrast (due to KVP), ^ density |
What helps the shape of an image? | FSS, SID, OFD |
What is Penumbra? | Geometric blur |
Focal Size Spot | Produces a better recorded detail |
An ^ in SID | v magnification size & distortion |
What doesnt effect SID? | KVP & Constrast |
The greater the SID | The v the geometric blur |
Best advice for OID? | place part as close to the cassette |
v OID | v Magnification & size distortion |
What is distortion? | Change in size & shape |
What is magnification? | Foreshortening & Elongation |