Screen Film Radiography Ace 2 PDF

X-RAY FILM  X-ray Film ▪ X-ray Film – used in recording of body images, made up of flexible thin transparent base coated on both sides with a sensitive emulsion.  SIZES OF FILM 8x10 Inches (20cm x 25cm) 10x12 Inches (25cm x 30cm) 11x14 Inches (28cm x 36cm) 14x1...

X-RAY FILM  X-ray Film ▪ X-ray Film – used in recording of body images, made up of flexible thin transparent base coated on both sides with a sensitive emulsion.  SIZES OF FILM 8x10 Inches (20cm x 25cm) 10x12 Inches (25cm x 30cm) 11x14 Inches (28cm x 36cm) 14x14 Inches (36cm x 36cm) 14x17 Inches (36cm x 43cm)  X-RAY FILM COLOR FACTORS (after developing) 1. Exposed to radiation without body part and developed – X-RAY FILM COLOR FACTORS (after developing) 2. Exposed to white light but undeveloped (unexposed to radiation) –  X-RAY FILM COLOR FACTORS (after developing) 3. Exposed to white light but developed (unexposed to radiation) –  X-RAY FILM COLOR FACTORS (after developing) 4. Exposed to radiation with Body part  X-RAY FILM COLOR FACTORS (after developing) 5. Fresh Film (unexposed to any kind of rays – PARTS OF X-RAY FILM PROTECTIVE COATING EMULSION LAYER ADHESIVE LAYER FILM BASE PROTECTIVE LAYER Also called Overcoat/ Topcoat/ Abrasion Layer. A cellulose layer that serve as protection in moving the film across the Intensifying screen. EMULSION LAYER The active layer (heart) of the Film Activated by light and radiation to create image. It is sensitive to both light and radiation The site where latent image was formed The heart of X-ray film. EMULSION LAYER Consist of homogenous mixture of gelatin and silver halide crystals. ▪ Gelatin – Provide support for the silver halide crystals. - porous for easily penetration of processing chemical. - made up of calf skin a colloidf extracted from cattle hooves & hives.  EMULSION LAYER Silver Halide Crystals – active ingridient of the emulsion. Commonly tabular in shape. 98% AgBr – light sensitive 2% AgI – x-ray sensitive ADHESIVE LAYER Also called substratum/ sub coating/ Subbing layer. Provides maximum contact between base and the emulsion layer when processing.  FILM BASE Foundation or support that allows the film to maintain shape and prevents unnecessary bending, which would cause artifacts. Provide support for the emulsion. Must be transparent or clear so as not to detract from the image. Made of polyester foundation that provides flexibility and transparency and other characteristics that are needed for an excellent film base. 3 GENERAL TYPES OF X-RAY FILM Screen Film – most commonly used film for radiographic IS. Uses 2 IS because of double emulsion. Characteristics that must be consider in selecting screen film:  Screen Film Contrast – the difference between adjacent densities. - the difference of contrast depends on size and distribution of silver halide crystals. High Contrast – smaller silver halide grains with relatively uniform size Low Contrast - larger grains that has wider range of sizes. Speed – the sensitivity of the screen film combination to x- rays and light.  Screen Film Spectral Matching - films are sensitive to various colors of light or its “ Spectral Response” - Properly matched to the spectrum of light emitted by screens. Orthochromatic Film – is called green sensitive film. Has tabular grains.  Screen Film Anti Crossover/ Antihalation Dyes – addition of light absorbing dye in a crossover control layer to reduce crossover to near 0. Crossover – exposure of an emulsion caused by light from the opposite side of the radiographic intensifying screens. Parallax Effect -  3 GENERAL TYPES OF X-RAY FILM Direct Exposure Film/ Non-Screen Film ▪ Non-Screen Film ▪ Single Emulsion/Coated layer (but thicker emulsion layer) ▪ Higher concentration of Silver Halide Crystals ▪ Used in High Exposure Factor (Higher Patient Dose) ▪ Pure X-rays Forms the Image. ▪ Used for imaging Thin Body parts  PARALLAX EFFECT / CROSSOVER PARALLAX EFFECT/ CROSSOVER: is the exposure of an emulsion by light from the oppositeside radiographic intensifying screen. Resulting to slight blurring of an image.  This effect is inherent in double-emulsion film, it cannot be stopped but can be lessen by adding a BLUE DYE on the BASE of the film.  ADDING BLUE DYE TO THE FILM ALSO CAUSES LESS EYE STRAIN AND IS EASIER TO LOOK AT!  3 TYPES OF X-RAY FILM ACCORDING TO SENSITIVITY NOTE: Types of film according to sensitivity in only applicable when using intensifying screens! MONOCHROMATIC FILM > Blue light sensitive film. >With globular grains (spherical and higher in volume) > sensitive to photon wavelengths emitted by Calcium Tungstate Screens. ORTHOCROMATIC FILM > Green light sensitive film. >With Tabular grains (Table-top like structure and higher in surface) > sensitive to photon wavelengths emitted by Rare Earth Screens. PANCHROMATIC FILM > Sensitive to all visible light spectrum (To all screens) (Needs to be in total darkness (requires no Safelight) X-RAY CASSETTE ▪ Cassette – are film holders used to transport film for use without exposing the film to room light. Have a metal frame with a thermosetting plastic (Bakelite material) or magnesium front.  SCREEN ▪ Intensifying Screens – are cardboard or plastic base structures that are usually found as pairs inside the cassette. It converts x-rays into light rays that is used in Image production. It also intensify the actions of X-rays. INTENSIFYING SCREENS  LEARNING OBJECTIVES: 1. Describe the usage of Intensifying Screens. 2. Explain the types of Intensifying screen. 3. Describe the different parts of intensifying screen. 4. Explain the use of Phosphor layer. TYPES OF INTENSIFYING SCREENS CAWO4 or Calcium tungstate: a chelate natural tungstate; Low speed 300-400 speed level. Thomas Edison. Barium lead sulphate: Used mostly in high KVP factors. 300- 400 Zinc Sulfide: Used mostly in Low KVP Factors. Rare Earth screens(Gadolinium Oxysulfide, Lanthanum Oxysulfide, Yttrium Tantalate): High Speed screens ranging from 900-1000. PARTS OF INTENSIFYING SCREEN SCREEN BASE REFLECTIVE LAYER PHOSPHOR LAYER PROTECTIVE COATING SCREEN BASE Thickest part of I.S serves to support the other components especially the phosphor layer. Must be rugged and moisture resistant Must not suffer radiation damage nor discolor with age Must be chemical inert and not interact with the phosphor layer Must not contain impurities that would be imaged by x – rays. REFLECTIVE LAYER A very thin layer of a white shiny substance, usually titanium dioxide. Serves to redirect the light toward the film. Intercepts light photons headed in other direction and redirects them to film. Made up of shiny substance such as magnesium oxide and titanium dioxide. HOW REFELECTIVE LAYER WORKS? PHOSPHOR LAYER Active layer within the screen Most important layer; the phosphor are able to convert xray energy to visible light PHOSPHOR LAYER PROTECTIVE COATING Is a cellulose layer that serves to protect the phosphor layer and reduce static build up from movement of the film across the screen. SPECTRAL MATCHING In order to create specific detail in the film, proper matching of intensifying screens must be made to produce desired image. The following are the proper matching of type of film (according to sensitivity) to Type of intensifying screens. Monochromatic Film > Calcium Tungstate (CAWO4) Orthochromatic Film > Rare Earth Screens Panchromatic > Any type of Screens COLOR SPECTRUM (ROYGBIV) SPECTRAL MATCHING Monochromatic film Calcium Tungstate >(R O Y G B V ) >(R O Y G B V ) > Sensitive to Blue light. > Emits Blue Violet light (Indigo to Violet) (400nm to >Sensitive to photon 450nm) wavelength (450nm) emitted from calcium > Lower Speed; because of tungstate. Broadband emission (many > Has Globular grains colors) (Spherical shape) GLOBULAR GRAINS SPECTRAL MATCHING Orthochromatic film Rare Earth Screens >(R O Y G B V ) >(R O Y G B V ) > Sensitive to Green >Emits green and blue Light. light but mostly green > Sensitive to photon > Gadolinium, Lanthanum wavelength emitted and Yttrium Tantalate. > from rare earth screens. High Speed; because of One > Has Tabular grains line emission/color (Flat shape) singularity/ specific color. TABULAR GRAINS >Oxysulfide – agent that emits green light. >Oxybromide – agent that emits blue light > Compounds can be Gadolinium/ Lanthanum Oxysulfide, Gadolinium Lanthanum Oxybromide. Yttrium Tantalate – emits G B V Colors. SPECTRAL MATCHING Panchromatic film Any type of screen >(R O Y G B V ) >(R O Y G B V ) >Sensitive to All light spectrum. > Either Calcium Tungstate > Remember: Needs or Rare Earth Screens total darkness in the darkroom (no safelight to be used!) CASSETTES (FILM HOLDERS) PARTS OF RADIOGRAPHIC CASSETTE CASSETTE FRONT CONTACT FELT/COMPRESSION LAYER LEAD FOIL CASSETTE BACK CASSETTE FRONT Made up of radioluscent (low Atomic No. (Z) material as bakelite or carbon fiber materials (low beam absorption). CONTACT FELT/COMPRESSION LAYER Maintains proper film-screen contact. LEAD FOIL Absorbs secondary radiation (backscatter). CASSETTE BACK Made up of steal or of lightweight metal such as magnesium. THANK YOU! DARKROOM What is DARKROOM The place where radiography starts and ends. (Radiography begins in the darkroom by loading the cassette with x-ray film and ends with the removal of the film, containing the latent image from the cassette. The film is placed in the processor, where it becomes a visible and permanent image after developing and fixing the film) IMPORTANT REQUIRE MENTS FOR AN EFFICIENT DARKROOM/ PROCESSING ROOM LOCATION AND SIZE PROTECTION AGAINST RADIATION VENTILATION CLEANLINESS COLOR OF WALLS ELECTRICAL WIRING LIGHT TIGHT ENTRANCE ILLUMINATION Location and Size Location ▪ In proximity and near the exposure room ▪ Must be accessible ▪ Burns – “The location should be at a place in the department that requires the radiographer to walk as few steps as possible’’ SIZE ▪ 15X9.5 ft (4.5x2.9m) = ideal size for darkroom that process 200 films/ day 2 SECTIONS OF DARKROOM DRY SECTION: L – loading bench F – Film Bin S – Storage cabinet C – Cassette Transfer Cabinet WET SECTION: P – Processing Tank W – Wash Tank ( Single and Cascade ) T – Temperature control Unit W – Wet Film Illuminator F – Film dryer/ Film hangers PROTECTION AGAINST RADIATION CONCRETE – Minimum/ must be 6 inches thick WOOD – should be coated with lead (1.5mm Pb – oneline coat; 0.75mm Pb Sandwich coat) Hallow blocks – should have cement fillings VENTILATION Darkroom Humidity Range – 40-60% Temperature rate – 65/67-83 degree Fahrenheit or 20 degree Celsius (18-24 degrees – old) AIR Movement – Ceiling fan = 15-25ft/min ▪ Exhaust fan = 8-10 room changes of air/hr. ( Should be light proof and able to filter out dust; may be maze type exhaust fan) CLEANLINESS MUST BE CLEAN; AVOID SMOKING, EATING AND DRINKING INSIDE THE DARKROOM. (TO PREVENT ARTIFACTS!) COLOR OF WALLS Light gray or Dark Colors Burns – IVORY COLOR ELECTRICAL WIRING Must be hidden; should not be octopus wiring to prevent static artefacts. LIGHT-TIGHT ENTRANCES An entrance which provides an easy access and complete protection against white light or outside light. ▪ Single Door – Simplest type; (Rubber sealer) – all corners of door are covered with rubber; Uses pass box to allow transfer of film without using the main door. ▪ Double door – A.K.A Light lock door – has interlocking mechanism ( a door on the other side cannot be opened unless the other is fully closed) ▪ Labyrinth / Maze type – Easy access door involves no doors but space consuming. ▪ Revolving/Rotating door – fast access – has a heavily tinted rotating glass capsule. ILLUMINATION WHITE LIGHT : For QA AND QC Maintenance; overhead light 2-4units (fluorescent lamps) – 48 inches each/ 8m2 length. Must have short duration of phosphorescence. SAFELIGHT : For illumination not detrimental to image quality. Most common cause of fog is safelight fog. QC – Every 6 months. ▪ 2 types of safelight. Safelight Bulbs Tungsten Bulb Amber Bulb Sodium Vapor (For busy darkrooms/For labyrinth maze type DR) LED  D.W.F DISTANCE, WATTAGE, FILTER DISTANCE AND WATTAGE 3FT IS TO 7.5 WATTS – For single coat emulsion 4FT/5FT IS TO 15WATTS – For double/duplitized emulsion 6FT – Exclusive for sodium vapor bulbs Point to Point Distance Manual : Between safelight and the working bench. Factors that results to Safelight 1. Safelight Exposure duration 2. Wrong wattage to Distance 3. Wrong Filter to Type of film DON’T BE CONFUSED! EMIT/PERMIT: “ALLOW TO PASS THROUGH” PROHIBIT: “NOT ALLOW TO PASS THROUGH” FILTER Filter out W.I.C.E – wavelength, Intensity, Colour and Energy A. WRATTEN 6B FILTER For monochromatic film (blue sensitive) Filter outs only wavelength and intensity Emits Red, orange and yellow color (amber light) A.K.A amber filter; KODAK Morlite filter. *WRATTEN 6B FILTER must filter out/prohibit wavelength of blue which is below 550 nm! *WRATTEN 6B FILTER emits only above 550nm to 635 which has colorof Red, Orange and Yellow. Therefore it is considered a safelight to monochromatic film which is blue color sensitive!  B. GBX2 FILTER For orthochromatic film (green sensitive) – also can be used in monochromatic film. Emits red light only Filter out wavelength, intensity and color. AKA. RED FILTER, all purpose/Multipurpose filter; KODAK 2FILTER; KODAK Dual filter  *GBX2 Filter must filter out/prohibit wavelength of colour green which is below 600nm! *GBX2 filter emits only above 600nm which has colour of Red only. Therefore it is considered a safelight to orthochromatic film which is green colour sensitive!  C. NO FILTER – For panchromatic film