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Fluoro
| Question | Answer |
|---|---|
| Formula for magnification | input diameter/output diameter input # is always larger |
| How do you get brightness gain? | minification x flux. it accelerates and focuses the electron beam on the II |
| Never use fluoro for? | positioning |
| Visually acuity is controlled by? | cones, phontonic |
| What lies between the input screen and the photocathode? | thin protective coating |
| Describe the function of the photocathode | absorbs light and emit e |
| what foes the output screen do? | Absorbs e and emit green light |
| Why is the input screen concave? | maintain same distance (input/output) and decrease vinetting? |
| What happens when greater voltage is applies to the electrostatic lens? | focal point moves closer to the input |
| What angles have the highest energy scatter? | greater than 90 |
| What does photoemmissive material do? | absorb light and emit e |
| Name the most common viewing system? | video |
| what did rads become martyrs? | wore the beam on their head, lack rad protection |
| what causes fluoroscopic resolution to vary? | minification gain |
| Fluoro contrast is affected by what | scatter, penumbra light, light scatter in the II tube |
| define vinetting? | decrease in resolution and contrast at image periphery |
| Why is fluoro the domain of the rad? | because it's dynamic |
| What invention enabled brightness to be enhanced? | II |
| What does flux gain do to image quality? | decrease image |
| What is a CCD | charged coupling device, stores image |
| what is the min source to skin distance for mobile fluoro? | 12 inch |
| What is the min source to skin distance of stationary fluoro | 15 |
| what is the dose to pt for cassettes | 30mR |
| what is the does for 105 mm film? | 10 mR |
| What is done to the output screen to produce high resolutions | thin screen and small phosphors |
| what is the diff from fluoro tube and dx tube? | SOD less than 15 |
| After x-ray photons leave the pt, what does it strike next? | input screen |
| what is the purpose of electrostatic lens? | to accelerate and focus e |
| what is abc and how does it function | maintain brightness, change the flow of e between input and output |
| ?what is in the input screen | CsI sodium activated cesium iodide |
| 1 incident photon = how many light photons? | 1500 |
| what is the Pb/eg for gloves and aprons in fluoro? | 0.25 mm |
| Name advantages a rad tech has over rad during fluoro? | not in the primary beam, and use rad as a shield |
| what reduced quantum mottle? | increase mA |
| define total brightness gain | minification x flux, measure the brightness intensity |
| Every year brightness gain deteriorates by? | 10% |
| Name the geometrical factor that alters recorded detail in fluoro? | mini gain, focal point, input screen, resolution, OID, size and phosphor thickness |
| what is the most common viewing system? | video/real time |
| Identify the rad tech responsibility during fluoro | assist rad, run post films (static) |
| Identify the steps in the process of an II tube | x-ray to light, light to e, e to green light |
| what does the math formula for minification gain | input diameter2/output diameter 2 |
| Describe how the video raster scanning pattern affects video viewing? | decrease resolution |
| what are the advantages for CCD? | eliminate lag |
| identify the minimum over the table exposure rates and what is the advantage range | 10R/min |
| how do you reduce pt dose when using mag? | collimate the shutters |