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Imaging 2 Final
Intro to Digital Radiography Final Review with Math
| Term | Definition |
|---|---|
| Flux Gain Formula | the number of light photons at the output screen/the number of light photons at the input screen |
| Minification Gain | (Diameter of the input screen/diameter of the output screen)^2 |
| Brightness Gain | Minification Gain * Flux Gain |
| Calculating Object size | Image size=Object size*Magnification Factor |
| Calculating Size Distortion | SID=Magnification Factor * SOD |
| Pixel Size formula | Pixel size=Field of View/matrix |
| SID Formula | SID=SOD+OID |
| Inverse Square Law | I1/I2=D2^2/D1^2 |
| Exposure Maintenance Formula | mAs1/mAs2=D1^2/D2^2 |
| Grid conversion formula | mAs1/mAs2=GCF1/GCF2 |
| 5:1 | 2 |
| 6:1 | 3 |
| 8:1 | 4 |
| 10:1,12:1 | 5 |
| 16:1 | 6 |
| Without a grid | 1 |
| Detective Quantum Efficiency | measures the efficiency of the detector to send useful signal to the image signal/noise ratio, by percentage |
| Modulation Transfer Function | Mathematical function that measures the ability of a detector to transfer its spatial resolution characteristics to the image. |
| Window Level | The center of the range of numbers in a digital image BRIGHTNESS |
| Window Width | The range of numbers in a digital image CONTRAST |
| Bit | Discrete units used by computers for processing information |
| Bit depth | number of bits per pixel |
| Intensifier Flouro Step 1 | INPUT SCREEN -coverts x-ray photons to light photons -coated with cesium iodide -Diameter range 13-30 cm |
| Intensifier Flouro Step 2 | PHOTOCATHODE -the light from the input screen strikes the photocathode -made of antimony cesium -emits photoelectrons |
| Intensifier Flouro Step 3 | ELECTROSTATIC LENSES -series of electrodes -accelerate and focus photoelectrons |
| Intensifier Flouro Step 4 | ANODE -small ring of metal with a charge -attracts photolectrons |
| Intensifier Flouro Step 5 | OUTPUT SCREEN -coated with ZnCdS -converts photoelectrons into light -diameter of the output screen is 1/10 the diameter of the input screen |