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Radiology 1030 Film
| Question | Answer |
|---|---|
| Describe the super coat layer and it's function | Hard protective gelatin, protects emulsion from scratches |
| construction of the film | base, adhesive, emulsion, supercoat |
| Explain the purpose of the gelatin | Acts as a neutral lucent supspension for halisde crystals, suspends and separates crystals, elar to permit light to travel through |
| What are the qualities of good film base | flexible, tough, rigid, uniformly lucent |
| What is adhesive used for | Glue to emulsion to the base, prevents distortion |
| describe what emulsion is composed of | gelatin adn silver halide crystals |
| what are the photosensitive agents suspended in the gelatin | silver halide crystals |
| Types of single emulsion film | mammo, fine detail, extremity, adn duplication film |
| Crystals are a maxtix of ehat atoms | silver, bromide and iodine |
| Crystal lattice is bound together by which type of bond? | ionic |
| what is the purpose of the sensitivity seck? | electrodes o attract free silver ions during latent image |
| What type of film is sensitive to all types of colors? | panchromatic |
| Know the latent image formation | 1-bromide ion absorbs an incident photon and ejects an e-. the ejected e- is trapped in teh sensitivity speck and gives a neg charge. The - e- attacts a free silver ion. The silver ion neutralizes sensitivity speck and repeat. |
| Know which type of fim had the fastest speed. | Faster film= larger crystal size and thicker emulsion |
| How should film be stored? | On end, away form cleaning solutions, fromaldehyde, chemicals and chemical fumes. |
| Describe artifact | any irregularity on an image that is not caused by the primary beam |
| What are the 3 areas where artifacts can occur | exposure, processing, and handling |
| Give 3 examples of exposure artifacts | pt motion, warped cassettes, double exposure |
| 3 examples of processing artifacts | pressure (darker/black), guide shoes marks, scrape(lighter/white) |
| How are processing artifacts eliminated | proper film storage |
| Whar causes guide shoe marks? | Guide shoes in turn around are sprung. |
| What are Pi lines | occur at 3.14 intervals- caused by dirt or chemical stain |
| What kind of artifacts can dirty rollers cause? | emulsion pick off, gelatin build up- sludge |
| What will chemical fog look like on the film | rafioation fog, usually dull gray |
| what is a diachroic stain? | yellow |
| Why are processing artifacts with Cr different than those with film? | Cr is electrical rather than chemical |
| Describe the cause of wet-pressure sensation marks | produced in teh developer tank, irregualr or diry rollers |
| What causes light or radiation fog | temp or humidity is too high, white light leaks |
| What causes kink marks adn what does the film look like | light before processing, dark after processing |
| what is the casue of static artifact on teh processed radiograph | lightening bolt, crown, tree, smudge |
| List 5 types of handling and storage artifacts that occur with DR | debris, discoloring, fogging, "ghost" image, bead |
| Whar causes hyporetention artifact and what does it look like | too old of film- yellow/brown |
| True of false- The film is more sensitive to radiation, light, anc chemicals before exposure than after | false, after exposure |
| True or false- when you take a radiolgraph trying to locate an object, it is not considered an artifact | true |
| Why are intensifying screens used | amplify incoming x-ray beams |
| What % of latent image is formed from light photons | 99% |
| What percentage of the latent image is formed by x-ray photons | 1% |
| Which type of film is uesed with intensifying screen | double emulsion |
| Name the layers of intensifying screen | base, reflecive, phosphor, protective |
| What is an important characteristic of the abse of an intensifying screen> | tough and flexible |
| Whar does a phosphor in teh intensifying screen do when struck by an x-ray | absorbs energy x-ray and emits light |
| what is the active layer in an intensifying screen | phosphor layer |
| How can teh prtective layer be damaged | nails and stains |
| what is the type of interactions between the x-ray photon and the phosphor | compton and photoelectric |
| what is screen speed | conversion efficemcy |
| What is spectral emmision | match sensitivity of film, ensure max. latent image formation |
| Differances between phosphorescence and fluorescence | Phospor- emit light after photon is disipated, Fluor- instantaneous |
| What is the delay in phosphorecent mission called | Screen lag or after glow |
| How long if the life of the intensifying screen | 5-7 yr |
| What is the atomic # range for rare earth phosphors | 57-71 |
| What is resolution adn what controls intensifying screen resolution | 1-size of phosphor crystals, and thickness of layer. 2- concentration of crystals |
| How are crystals adn layer thickness related to both resoltion and screen speed | 1-inversely related to resolution 2- directly related to screen speed |
| What is quantum mottle? | graying, insufficient quantity of protons striking the screen |
| How is quantum mottle eliminated | Increasing mAs |
| How is speed of an intensifying screen increased | increase kvp |
| How should the cassette be stored | on end, upright |
| What does poor screen/film contact produce | decreased image density |
| Name the 4 steps of automatic processing | developer, fixer, waher, dryer |
| Name all of the agents in the developer solution | Reducing agent, activator, restrainer, preservative, hardener, solvent |
| What 3 things control the action of the developer | immersion time, solution temp, and chemical activity |
| Describe what reducing agents do | provides electron to silver ionattached to sensivity speck, converts black to metatlic silver |
| What is the function of the retrainer | restrict the reducing agent |
| What is the funtion of the hardener | conrols teh swelling of the gelatin |
| What is the funtion of the preservative | decreases teh oxidation of reducing agent |
| What is the solvent? | water |
| true or false- the developer is the only solution that is framitically affected bt contamination | true |
| what will films that are in contaminated developer look like | appear gray |
| what is the most common cause of developer contamination | leaving the processor lid down- the fixer can drip into the developer |
| What is the promary agent in fixing | clearing agent |
| what other agents are used in fixer | activator, perservative, hardener adn solvent |
| Whar is the name of the clearing agent | ammonium thiosulfate, removes undeveloped silver halide crysals |
| What is the function of the activator | enahnces the clearing agent |
| What is the funtion of the preservative | desolves silver for continual removal of emuldion |
| What is the function of the hardener | prevents scratches and maintains a uniform thickness |
| What is the solvent | water |
| Over time what can happen to the fixer and what can be done to correct if | it is unable to accept additional silver, clear tank |
| What are the 2 steps of archiving? | washing and drying |
| How long should films be stored | 5-7 years |
| name the subsystems of the automatic processor | transport, replenishment, temp regualtion, recirculation, dryer |
| What does the transport system do | moves through all sections of the processor. Controls the length of time film is immersed in solutions |
| What does the transprt rack do | moves film up and down out of solutions |
| What does the cross over rack do | turns films into the next tank |
| What does the drive system do | turns the rollers |
| What does the replinishing system do | replaces depleated chemicals in developer and fixer |
| what deos the circulation system do | stabilizes the solution temp, agitates the solutions, mixes replinishinment chemicals into tans |
| What does the temp control do | maintains solution temp |
| 90 sec processor temp is | 92-96 |
| List several silver recovery systems | metallic, replacement, electorlytic, chemical precipitation, resin |
| What is senitomotry | measurement of resposes of film to exposure and processing |
| What is a penetrometer | Series of increased thickness absorbers- produces a step wedge. Made out of aluminium |
| What is a sensitometer | expose a reproducable, uniform, optical wedge onto a film |
| What is a densitometer | provides a reading of teh amount of blackening on a film |
| What is optical distense (OD) formula | incident light/transmitted light |
| What does the horizontal axis represent | log exposure |
| what does the veritcal axis represent | density |
| What are the 5 parts of teh D log E curve | base fog, toes, straight protion, shoulder, d max |
| Define base + fog | desity with no exposure |
| Define the toe | region of the curve. Controlled by phenidone *controls the subtle grays* |
| What is the staight portion | Between the tow and shoulder, Film reacts in a linear fashion to exposure |
| What OD # fit in the straight line portion | 0.5-1.25 |
| What is the shoulder | Heavy black tone- controlled by hyfroquinone |
| What is Dmax | Film capible of recording the highest point of the D log E curve. All silver haides have a full complement of silver atoms and can't accept more |
| What 4 thins can be expressed by the D log E curve | resolution, speed, contrast, latitude |
| What determines resolution on the curve | ability to accurately image an object detail, sharpness, definition, adn resolving power |
| What is the relationship between resolution adn crystal size | small crystal darkens small areas, Large crystals darken large areas. Inverse relationship exists between film resolution and crystal size |
| What is speed | amount of density, blackening, a film produces for a given amount of exposure |
| What controls the speed of the curve | the sctivity of phenidone becuase it affects the toe of the curve |
| What is the relationship of film speed to crystal size | large crystal means a faster speed |
| What is contrast | slope of the straigh line portion of the curve |
| A steep slope of the straight line will have ______ conrast | increased |
| What is latitude | range of exposured that will produce densities within the diagnostic range |
| How latitude and contrast are related | inverely related, as contrast increases, latitude decreases |
| low contrast films will have _______ latitude | increased |
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