Wk 3 Image Receptors PDF

Types of image receptors 1. Intraoral conventional films 2. Digital intraoral sensors 3. Photostimulable phosphor (PSP) plates 1. Intraoral conventional films 2. Digital intraoral sensors 3. PSP Intraoral X ray film (conventional) –Is a double emulsion film (emulsion coated on both sides)...

Types of image receptors 1. Intraoral conventional films 2. Digital intraoral sensors 3. Photostimulable phosphor (PSP) plates 1. Intraoral conventional films 2. Digital intraoral sensors 3. PSP Intraoral X ray film (conventional) –Is a double emulsion film (emulsion coated on both sides) –May contain one film or two films (one film or two film packet) –Two film packet to make duplicate record –Available in different standard sizes –Have occlusal dot on tube side  Significance of dot – To determine orientation of film – After processing it helps to distinguish between left and right sides of the patient – Useful in mounting of the film ▪ Conventional Intraoral film packet Contains ▪ X-Ray film ▪ Black paper wrap/ paper film wrapper ▪ Lead foil sheet ▪ Outer wrapping(soft packet) a-Tube side(white surface) b-Label side(color coded)  Tube side- – white color – has raised dot – Must face the tooth surface Label side – Color coded side should face the tongue – Mentioned speed and name of manufacturer – Number of films inside  Paper film wrap – protective sheet to shield film from light Lead foil sheet – A single piece of lead sheet – Located behind the film and paper – Protect shield from back scatter – Have embossed pattern if the film is placed backward and exposed  Film Base Made up of polyester plastic to support the emulsion Has Thickness of 0.2 mm and is flexible Should be uniformly translucent with blue tinge Adhesive layer Thin layer of adhesive material placed on both sides Added before applying the emulsion Serves to attach emulsion to the base Film Emulsion Coating applied to both sides of the base Has sensitivity to x rays Homogeneous mixture of Silver halide and gelatin Gelatin used as carrier vehicle to evenly disperse silver halide crystals During processing – gelatin absorb the chemicals to react with silver halide Sizes of the film Three sizes 0, 1, and 2 0 – 22 x 35 (small children) 1 - 24 x 40 (anterior teeth) 2 - 31 x 41 (adult film) Intraoral sensors Small detector placed intraorally to capture radiographic image - Wired sensors (direct) or wireless sensors (indirect) Sensors with fibreoptic cable are linked to computer – called as solid-state detectors  Direct digital imaging Charge-coupled device (CCD) Complimentary metal oxide semiconductor (CMOS) Indirect digital imaging Photostimulable phosphor Digital intraoral sensor  Charge-coupled device (CCD) – first digital image receptor used for intraoral imaging (1987). – Uses a thin wafer of silicon as the basis for image recording. – The silicon crystals form the pixel matrix – When exposed to x rays, A charge pattern is formed from the individual represents the latent image – The charge pattern is transmitted as voltage to Analog-to-digital converter – Voltages from each pixel are sampled and assigned a numeric value representing a gray level that forms an image on the screen  Complimentary metal oxide semiconductor (CMOS) – Same as the CCD – silicon semiconductors – The charge pattern is directly connected to a transistor as a small voltage – The voltage is read by a frame grabber and displayed as a digital gray value. – Less costly than CCD  Photostimulable phosphor Wireless system Absorb and store energy from x rays and then release the energy as light (phosphorescence) when stimulated by another light of an appropriate wavelength. The PSP material used for radiographic imaging is “europium-doped” barium fluoro-halide. Combined with polymer and coated on plastic base as conventional film Phosphor plates and scanner Y  X ray Film holders Rinn's film holders, also called XCP (X-tension C-one P-paralleling), are devices used for intraoral radiographs applying the paralleling technique. They ensure that film will be perpendicular to X-rays. Their colors can be: Yellow for posterior teeth (molars and premolars)  Blue for anterior teeth (incisors and canines) Red for bite-wing radiographs Green for radiographs with the rubber dam is still on. v Film holders for conventional films  Other film holders v Snap-A-Ray Phosphor plate holder