Xray film types and construction [Autosaved].pptx

presentation on xray film types and construction

1. X-ray film types and construction PRESENTED BY SARITA GAIRE BSC.MIT 1 ST YEAR ROLL NO: 160 MAHARAJGUNG MEDICAL CAMPUS

2. Table of contents. Introduction to x-ray film. History of x-ray film. Feature of x-ray film. Construction of x-ray film. Types of x-ray film. References.

3. WHAT DO YOU MEAN BY X-RAY FLIM? X-ray film is a radiographic receptors or materials used to make images. Helps to record the information regarding the object(tissue) through which the x-ray passes & hence they greatly help in diagnosis, treatment of the patient problem.

4. History of x-ray film. First x-rays were recorded on glass plates. 1917: cellulose nitrate film base is widely adopted but it was flammable. 1923: cellulose triacetate is used as safe film base. 1932: blue tint is added x-ray film to reduce eye strain. 1960: polyester film base – “ Dupont ” as cellular triacetate built it is more resistant to wrapping room edge and stronger than cellulose triacetate.

5. Features of x-ray film. it must be strong and flexible. It must be uniform in thickness. It must be dimensional stability throughout the processing. It must be uniform in color. It must be transparent.

6. Construction of x-ray film. Basically , X-ray film consist of four layers: Film base. Subbing layer. Emulsion layer. Super coat.

7. 1.Film base . Is the central layer of the film. Previously made from cellulose nitrate but discarded because of many faults. In 1924 Eastman kodak company used cellulose acetate which was more flammable. In 1960s, polyester base was introduced and presently all x ray film have polyester as base material( dimethyl terephthalate +ethylene glycol) Thickest part of the film and thickness is about 0.18 mm. Provides support for the emulsion. Base is single .

8. Characteristics of film base. Dimensional stability Non-flammable Flexible ,strong , and of uniform thickness and color Low light absorption. Optical clarity(Transparent).

9. Functions of film base. To provide support for emulsion layer. To transmit light so that the image can be viewed.

10. 2.Subbing /adhesive/substratum layer Subbing layer lies between the base and emulsion and called adhesive layer or substratum layer. Made of mixture of gelatin solution and solvent of film base The subbing or adhesive layer is required between the base and emulsion for two reason: 1. To ensure that the emulsion layer adheres to the smooth and shiny base material during coating stage in manufacture. 2. To prevent any separation of the emulsion layer from the base during processing. It might occur when the emulsion swells and contract during processing..

11. 3.Emulsion layer. Most important layer in X-ray film. In this layer x ray/light photon interact and transfers information. thickness = 3 to 5µm. Consists of silver halide crystal suspended in gelatin, silver halide used in x ray film are AgBr (92- 98%) , AgI ( 2-8%) and AgCl is also used.

12. Silver halide crystals In emulsion it is in form of small crystals. Which may be tabular, globular, polyhedral , or irregular in shape AgX crystal is cubic lattice. Crystal are about 6.3*10^10grain per cc of emulsion and different shape of grain were used such as globular ,cubic, hexagonal and square but nowadays, Tabular shaped (T-shaped) is used

13. Older irregular crystals Newer flat crystals

14. Advantages of T-shaped grain. It has large surface area which increases the film speed. Reduction in silver coating weight . Increased resolution due to reduction in cross over.

15. Construction of emulsion Mixture of silver nitrate and alkali halides are added at controlled rates. Mixing On mixing reaction occurs and forms potassium nitrate and insoluble precipitate of silver bromide crystals. The speed of mixing determines grain size distribution(GSD) that determines the contrast sensitivity . Shredding and washing Unwanted potassium nitrate is set ,shred and washed in water & the silver halide remains.

16. Ripening and digestion The gel undergoes repeated heating and cooling this process is called ripening and digestion. This increases the size of halide crystals which form sensitivity centers. The average grain size affects the sensitivity (speed) of the emulsion Add-ons Agents likes sensitizers are added to increase response of emulsion to radiation and control spectral sensitivity, Anti frothing agents are added to prevent the formation of air bubbles during coating Hardeners, plasticizers, bactericides and fungicides help emulsion to survive the rigours of photographic processing.

17. Gelatin. It is a transparent material mainly obtained from cattle bone and skin.

18. 4.supercoat Also called abrasion layer. It is the outermost layer and a thin layer of clear gelatin which is applied to emulsion. Its thickness varies from 5 to 10µm.

19. Function of super coat. Protect sensitive emulsion layer from effect of light pressure or abrasion. Provide shiny and smooth surface. Provide suitable surface characteristics and also to protect from mechanical damage. To reduce static spark.

20. Anti-curl layer. This layer is present only in single sided emulsion sheet films. In order to prevent the curling tendency with single sided emulsion film, the emulsion layer is balanced by coating the base on the opposite side to the emulsion firstly with the subbing layer and then with a layer of gelatin.

21. Anti-halation layer . It is a phenomenon characterized by the formation of a diffuse image or halo around the proper image. This occurs mainly in single sided emulsion film. When the image is formed by light, some of the incident light photon reached on base and return to the emulsion causing diffuse shadow around the image which is called halation.

22. Method to prevent halation. Adding a colored dye to non curling layer. Adding light absorbing dye to a base.

23. Adding colored dye to non-curling layer It is preferred for single sided emulsion film. These dyes are removed during development . Dye color selected is always the opposite or ‘complementary’ color to the exposing light, consequently the incident light will be absorbed by baking and not reflected e.g., a yellow dye will absorb blue light ,a red dye will absorb green light and so on.

24. Adding light absorbing dye to base These dyes cannot be removed during development. Dyes introduced in the base is carefully controlled because it increases the density and may interrupt the transparency of the film.

25. Crossover effect. It is a type of halation which occurs when film is used with intensifying screen. When the light emitted by a radiographic intensifying screen , it not only exposes the adjacent emulsion it can also expose the opposite side emulsion ,the light crosses over the base and blur the image called as crossover effect. It occurs only with double emulsion screen films . It causes blurring of an image therefore reduce details on the film.

26. Irradiation It is the sideway and scattering of light within the emulsion itself as a result of light striking the grains of AgX comprising the emulsion. It decreases the image sharpness. Least likely to occur in thinly coated emulsion.

27. Classification of radiographic film Radiographic film Double emulsion film Single emulsion film Screen type-general radiographic film Non screen type(direct exposure film ) Dental film(in OPD) Kidney surgery film Radiation monitoring film Not in use Screen type Mammographic film Non screen type CRT film Duplication film Photofluorographic film Laser imaging film(ER,X-ray) Thermal imaging film(X-ray, mammo,IR, CT & MRI) Not in use

28. Based on coating : A. Single emulsion film. B. Double emulsion film. Double emulsion film Single emulsion film

29. A . Single emulsion film Having emulsion layer in one side of the film. It is of two types i.e. 1. Screen type film. 2. Non-screen type film.

30. 1.Screen type film : This type of film is used in conjunction with a cassette fitted with a single intensifying screen. One application is mammography. The films are medium to high contrast. It can demonstrate microcalcification in soft tissue.

31. 2.Non-screen type film Also called direct exposure film. It is of following types : Photofluorographic film Cathode ray tube or TV monitor Polaroid film Duplication / Copying film Substraction film Laser film(dry pro film) Thermal film(dry star film).

32. Photofluorographic film : They are used to record the image produced at output phosphor of image intensifier tube. This type of film is single sided non-screen film. Orthochromatic or panchromatic fine grain emulsion are used.

33. Cathode ray tube or TV monitor : Its application in the following imaging modalities : Ultrasound Computerized tomography Magnetic resonance imaging Nuclear medicine Digital substraction imaging The emulsion are orthochromatic of medium to high contrast .

34. Polaroid film : A polaroid film pack comprises positive and negative film sheets plus a pod of jellified processing chemistry. Particularly used for recording USG scan image

35. Duplication / Copying film : It is used to duplicate the pre-existing film. It is a single emulsion film that is exposed to uv light or blue light through existing radiograph to produce a copy. It has an average gradient of -1.

36. Substraction film : It is a technique employed to remove unwanted images from a radiographic and thereby have important diagnostic information more readily visible. It is used in angiography. It is single emulsion film.

37. Laser film(dry pro film) : It is a silver halide film sensitized red light or laser light. A laser printer uses digital electron signal from an imaging device. It is light sensitive therefore laser film must be handled in total darkness. It is high-contrast single emulsion film with extremely fine grain.

38. The dry pro film High quality silver based material coated. The heat /laser light sensitive layer contains silver halide crystal. DRYPRO Film also a type of laser film having high-resolution. It is infrared sensitive film that needs no wet film processor.

39. Thermal imaging film(dry star film) Direct thermal printing dry star dry imaging films are designed to produce the highest diagnostic gray scale hard copies. Blue base. Daylight film loading(film are in sensitive to light). 100 sheets per box. Shelf life to be used minimum 18 months from packaging date. Relative humidity 30-60% Storage temperature 5-24 degree Celsius.

40. Advantages & disadvantages of single emulsion film. Good image quality/details Less expensive Curling problem More exposure required More radiation dose to the patient Decrease the image contrast

41. B.Double emulsion film Having emulsion layer in both side of the film. It is of two types i.e. Screen type film Non-screen type film

42. 1.Screen type film : This type of film has emulsion on both side of the base layer. This film is used for general radiography in between two intensifying screen. For examples : Extremities, chest, abdomen, skull radiography etc .

43. 2.Non-screen type film(direct exposure film) : Also called enveloped wrapped or non-screen film because of its exposure to x-rays alone. It is much slower than a screen film combination. It is used due to their superior resolution compared to the screen type film. Used for extremity radiography where fine bony detail is required. It is of following types : a. Intra-oral dental film b. Kidney surgery film c. Radiation monitoring film

44. a.Intra -oral dental film : Intra-oral dental film are the most common type of dental x-rays films. It provide a lot of detail and allow dentist to find cavities, check the health of the tooth root and bone surrounding the tooth. It is of following types : 1. Periapical 2. Occlusal 3. Bitewing

45. 1.Periapical x-rays film : This type of film shows the whole tooth from crown to beyond the end of the root. Periapical x-rays are used to detect any abnormalities of the root structure and surrounding bone structure.

46. 2.Occlusal x-rays film : This type of film are larger and shows full tooth development and placement. Each x-rays reveals the entire arch of teeth in either the upper or lower jaw.

47. 3.Bitewing x-rays film : This type of film shows details of the upper and the lower teeth in one area of the mouth. Each bitewing shows a tooth from its crown to about the level of the supporting bone. It is useful in determining the proper fit of a crown and the soundness of fillings.

48. b.Kidney surgery film : This is a duplitized non-screen film designed to enable to radiographic exposure of kidney during removal of stone during surgery. Each packet contains two films, one with fast emulsion and the other slow. Thus, the two film features allows a wide range of renal stone densities to be demonstrated for any given exposure.

49. c.Radiation monitoring film : Like dental film in appearance but has one very important difference i.e. On one side of the base is a high-speed emulsion, while on the other side is a slower emulsion. Permits a wide range of exposure level to be recorded.

50. Advantages & disadvantages of double emulsion film Radiation dose to the patient and staffs are reduced. Wear and tear of the x-ray tube are reduced. Increase image contrast. Increase sensitivity: Adequate image density can be achieved from small exposure. Loss of image quality Expensive-due to economical reason double film use a higher coating weight of silver than single coated film and is an expensive and diminishing world sources.

51. Difference between single and double coated emulsion film characteristics Single coated Double coated Emulsion layer One sided Both side Patient radiation dose more less Radiographic detail more less Average gradient(G) Vey less more contrast Less more Non curl back layer present absent

52. Difference between non screen and screen Non screen screen Exposed with Only x rays Mainly by visible light used Without screen With screen Emulsion layer thick thin Image formation In deep superficially Processing time more less resolution more less Characteristics curve No apparent shoulder region in useful density range. Shoulder region within useful density range. Screen artifact no less Exposure dose more less Used in Dental, orbit, extremities also in industrial radiography. General radiography

53. Spectral sensitivity Spectral sensitivity is the range of wavelength of the electromagnetic radiation that the film will response. On the basis of spectral sensitivity, there are 3 types of film. They are : Monochromatic film Orthochromatic film Panchromatic film.

54. Monochromatic film : Radiographic film sensitive to single color commonly [blue color] of light spectrum is called monochromatic film

55. Orthochromatic film : Radiographic film sensitive to blue and green color of light spectrum is called orthochromatic film.

56. Panchromatic film : Radiographic film sensitive to all color of light spectrum is called panchromatic film.

57. Storage of film Storage Areas:- The hospital or x-ray department store The dark room The imaging room

58. Film storage Film must be placed in vertical position (date wise) and not horizontally to prevent static marks caused by discharge energy of static electricity due to pressure.

59. Care and protection of film Film should be protected from Physical change Light High temperature High relative humidity Harmful gases and fumes X-rays and radioactive source Fire and theft

60. X-ray films used in TUTH X-ray film used in Radiography : Both Laser and Thermal imaging X-rays films used in digital mammography : Thermal imaging film X-ray films used in CT Scan : Thermal imaging film X-ray film used in MRI : Thermal imaging film X-ray film used in DSA and Fluro: Thermal imaging film

61. references Chesney's radiographic imaging , John Ball & Tony price, 6 th edition Internet Slideshare.com

62. Thank you