Creating the Image Unit III 2013 Delmar Cengage

Creating the Image Unit III © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Radiographic Film Chapter 19 © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Objectives • Describe components of radiographic film • Explain production of silver halide crystals • State purpose of various additives to radiographic film • Describe latent image formation © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Objectives • Discuss differences between direct exposure film, screen film, and films for various special applications, such as duplication • Explain the fundamentals of proper film storage and handling © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Objectives • Identify common radiographic film artifacts • Discuss automated and daylight loading film systems • Explain responsibilities involved in proper radiograph identification © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Photosensitive Film • First image receptor chosen by Röntgen • No longer most common image receptor because of predominance of digital imaging in 21 st century • Knowledge of film/screen technology still required of radiographers © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Radiographic Film Construction • Base • Adhesive layer • Emulsion • Supercoat (overcoat) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Radiographic Film Base • Foundation of radiographic film – Flexible, yet durable – Uniformly radiolucent – Film must retain its size and shape throughout use and processing – Thickness ranges from 150 -200 micrometers – Modern base is thin sheet of polyester © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Base History • Original base: – Glass • Plates coated with emulsion – Difficult maintenance • Exposure factors with plates very high • Origin of term “flat plate” of abdomen © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Cellulose Nitrate • Replaced glass plates during World War I glass shortage • Highly flammable • Led to several devastating hospital fires in 1920 s and 1930 s © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Cellulose Triacetate • Safety base introduced in 1920 s – Less flammable than Cellulose Nitrate • Disadvantages: – Films would warp with age – Not as resilient as today’s polyester films © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Polyester • Base of today’s modern film • Introduced in 1960 s © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Specializations of Film Base • Blue tint – Reduces eyestrain – Increases diagnostic accuracy • Crossover – Light from one screen exposed opposite emulsion • Halation © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Cassette Loading • Single emulsion film – Emulsion side toward intensifying screen • Emulsion side dull • Non-emulsion side shiny – LL – notch in film in lower-left corner © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Adhesive Layer • Binds emulsion to film base – Allows for proper emulsion distribution over base throughout use and processing © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Emulsion • “Heart” of film • Composed of silver halide crystals suspended in gelatin – Active ingredient photosensitive • Silver halide crystals • Typically 5 -10 micrometers in thickness © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Gelatin • Allows even distribution – Separate suspension of silver halide crystals • • Radiolucent Non-reactive Processing chemistry able to penetrate Low Z# © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Types of Silver Halide Crystals • Silver bromide • Silver iodide • Silver chloride © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Duplitized Film • Double emulsion or double coated film © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Supercoat/Overcoat • Protective layer of gelatin – Provides sturdiness to unexposed radiographic film – Antistatic – Reduces damage from scratches, pressure, or contamination during storage, handling, and processing © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Manufacturing Radiographic Film • All must take place in total darkness: – Crystal production – Ripening – Mixing – Coating © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Silver Halide Crystal Formation • First step: – Pure metallic silver dissolved into nitric acid • Forms silver nitrate • Second step: – Silver nitrate combined with potassium bromide © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Silver Halide Crystal Formation • Combination yields silver bromide and potassium nitrate • Potassium nitrate is water soluble – Dissolves in water and washes away during production of emulsion © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Silver Halide Crystal Structure • Resultant shape can be many varying forms – However, inner structure takes on cubic form or cubic lattice © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Sensitivity Speck • Silver-gold-sulfide creates imperfections in crystals – Gives crystals good imaging properties – Result: • Sensitivity center or sensitivity speck within crystal lattice © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Sensitivity Speck • Allows for collection of many silver atoms in one area after being exposed to x-ray or light photons © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Ripening • Length of time crystals need to grow – Size and emulsion influence film factors • After ripening complete: – Emulsion cooled – Shredded and washed • Removes potassium nitrate © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Mixing • Shredded emulsion heated and melted – Specific temperature – Sensitizes crystals © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Mixing • Several extra ingredients may be added – Dyes • Adjust spectral sensitivity – Fungicide/bactericide – Antifogging agents © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Spectral Sensitivity • Panchromatic – Sensitive to all wavelengths • Orthochromatic – Not sensitive to red • Controlled by dyes added during mixing © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Coating • Requires precise and expensive equipment • Generates 40” rolls of film • Layers on adhesive, then emulsion, then supercoat • Film cut to size © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Latent Image Formation • Gurney-Mott Theory (1938) • X-ray and light photons deposit energy into silver halide crystals © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Latent Image Formation • Energy disrupts bonds between atoms of crystal – Electron freed – Halide migrates into gelatin – Silver ion remains © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Latent Image Formation • Sensitivity speck “traps” electron • Silver ion attracted to sensitivity speck to neutralize it • Process repeats itself © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Types of Film • Direct exposure (nonscreen) • Intensifying screen • Duplication © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Film Storage and Handling • Prior to exposure: – Storage • On end – Age • Expiration dates – Rotate stock – Heat • Below 68ºF (20ºC) © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Film Storage and Handling • Prior to exposure: – Humidity • 30 -60% – Light – Radiation © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Film Identification • Each exposure must include medical record information – Date of exposure – Full name of patient – Name of institution – Name of ordering physician – Patient identification number – Type of exam © 2013 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.