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Radiology Chapter 38 Foundations of Radiology, Radiographic Equipment, and Radiologic Safety.

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Presentation on theme: "Radiology Chapter 38 Foundations of Radiology, Radiographic Equipment, and Radiologic Safety."— Presentation transcript:

1 Radiology Chapter 38 Foundations of Radiology, Radiographic Equipment, and Radiologic Safety

2 Uses of Dental Radiographs
Detect dental caries in the early stages Identify bone loss in the early stages Locate abnormalities in the surrounding hard and soft tissues Evaluate growth and development Provide information during dental procedures (ie root canal) Document a patient’s condition at a specific time

3 Properties of Radiographs
X-rays are a form of energy X-rays belong to a group classified as Electromagnetic radiation Electromagnetic radiation is made up of photons that travel through space at the speed of light in a straight line with wavelike motion Shorter the wavelength the Greater its energy

4 Dental X-ray Machine Tubehead—tightly sealed—contains tube
X-ray tube—in the heart of the system Cathode—negative electrode Anode—positive electrode Position Indicator Device (PID) Extension Arm Control Panel Master Switch and indicator lights Exposure Button Milliamperage Kilovoltage selector

5 Types of Radiation Primary Secondary Scatter Leakage
X-rays that come from the target to the x-ray tube, (the useful beam) Secondary Created when the primary beam interacts with matter (less penetrating, not useful) Scatter Form of secondary, that is deflected from path in all directions (dangerous to all) Leakage

6 Characteristics of Radiograph Beam
Quality, quantity and intensity of beam Determine contrast, density and image detail (good x-ray)

7 Radiolucent and Radiopaque Characteristics
Structures that radiation can pass through easily (dark) Such as: Radiopaque Structures that radiation cannot pass through easily (light)

8 Contrast Images appear in a range of shades Black to white Ideal?
Higher kVp produces more penetrating radiograph and lower contrast 90 kVp requires less exposure time and produces low contrast on x-ray (more shades of gray 70 kVp requires slightly longer exposure and gives high contrast (fewer shades of gray)

9 Density Overall blackness or darkness of a film
Should enable view of air spaces (black) and enamel, dentin and bone (white) and tissue (gray) mAs control amount of time given to the exposure of x-ray

10 Other factors that Influence Density
Distance from the x-ray tube to the patient It changes the exposure setting and will be light or less dense Developing time temperature Process time too long, will appear dark Body size of patient Very small/thin—requires less rad than heavier patient

11 Geometric Characteristics
Sharpness Reproduction of fine details, and/or outlines Such as TV control (fuzzy) referred to as penumbra Focal spot size Film composition Movement

12 Geometric cont Distoration Magnification
Disproportional change in size of images Too much or too little vertical angulation Magnification Proportional enlargement of radiographic image

13 Radiation Effects ALL ionizing radiation is harmful
Tissue damage—radiation that is absorbed can result in chemical changes and biologic damage Ionization—can cause disruption of cellular metabolism and permanent damage to living cells and tissue Biologic effects—can take many years to become evident Cumulative effect– tissues can repair some damage, tissue does not return to their original state

14 Effects cont. Acute and chronic rad exposure
Acute—large does in short period of time Chronic—small amounts absorbed repeatedly over long period of time Genetic and somatic effects Genetic- (sperm and ova) passed on to succeeding generations, genetic mutations Somatic- (body) not passed on to future generations

15 Effects cont. Critical Organs Thyroid gland—(how do you protect)
Skin—seen as reddening or erythema Thyroid gland—(how do you protect) Lens of eye—can cause cataracts Bone Marrow--leukemia

16 Radiation Measurement
Traditional system or standard system (older system of measurement) Roentgen (R) radiation absorbed dose (rad) and roentgen equivalent in human (rem) System Internationale (newer system) Metric equivalent Coulombs per kilogram (C/kg), gray (Gy), and sievert (Sv) UNDERSTAND each system


18 Maximum Permissible Dose
Occupation persons = 5.0 rem per year Non-occupation persons = 500 mrem per year

19 Radiation Safety Background radiation—comes from natural sources
Protective devices Aluminum filtration ? Collimator ? Position Indicator device ?

20 Safety cont. Patient protection
Lead apron and thyroid collar Fast-speed film Film-holding devices Exposure factor Proper technique What does the ADA and FDA state regarding pregnancy and dental radiation?

21 Safety cont Operator protection and monitoring What are the rules ?
Never stand in direct path of primary beam Always stand behind lead barrier or stand at right angles from beam Never stand closer than 6 feet from the x-ray unit

22 Safety Equipment monitoring What is the ALARA concept?
What are the rules What is the ALARA concept?

23 Chapter 39 Dental Film and Processing Radiographs
What is a film holder ? Explain some of the few holding systems that are available

24 Dental Film Understand the following Film composition Latent image
Film speed

25 Intraoral Film Understand the following Film packet Outer packet
Packet info, wrapper and lead sheet, package positioning, package disposal Outer packet Tube side, label side Film sizes #’s 0, 1, 2, 3, 4 (what is each size used for)

26 Extraoral film Film packaging ? Film cassette ? Intensifying screen ?

27 How and where do you store film ?
If you were duplicating film what equipment would be needed?

28 Film Processing What are the five steps in processing film
What are the requirements for a film processing darkroom? Know the techniques/steps for Manual and Automatic film processing

29 Errors Fully understand the possible errors that can take place while processing films How would you correct or prevent these errors

30 Chapter 40 Legal Issues, Quality Assurance, and Infection Control
Regular testing to detect equipment malfunctions, planned monitoring and scheduled maintenance

31 Legal Considerations Federal and State regulations ?
Licensure requirements ? Risk management—polices and procedures that reduce chance of lawsuits Key areas Patient consent, patient records, liability issues and patient education Informed Consent Liability

32 Cont Patient records Patient Refusal Patient Education
(Understand all of the above)

33 Quality Assurance What is a quality control test and what does it monitor? There is a lot of information under Quality Assurance, make sure that you understand each type and the steps involved

34 Administrative Quality Control Steps
Develop and maintain a written description of the quality assurance plan Assign specific duties to staff members and ensure that each individual is thoroughly trained Maintain records of monitoring and maintenance Review the plan periodically and revise if needed

35 Infection Control There is a high risks for cross-contamination
CDC has guideline for Infection control (make sure you know them) There is a checklist for Infection Control during radiographs, be familiar with these steps

36 ICE There are procedures that can be performed for equipment and supplies Understand these procedures, such as how to handle film, film packets, holders. Procedures during and after exposure must be followed: What are these procedures; such as drying exposed film, etc.

37 Infection Control Steps
There are several steps to practice during film exposure Some are common sense and others are not Read and think about the many ways you can practice this. Such as barriers for operatory, washing hands, how to unwrap an exposed film or how to transport an exposed film

38 Chapter 41 Intraoral Radiography
Steps to quality radiographs Placement Exposure Processing = Quality radiographs

39 Full Mouth Series Intra oral films What type of x-rays are take in FMX
Two types of methods for exposing intra oral films

40 Paralleling Technique
Five basic rules Film Placement—cover teeth involved Film Position—parallel to long axis of tooth Vertical Angulation—central ray perpendicular to film and long axis Horizontal Angulation central ray directed through contact areas Central Ray—beam must be centered on the film

41 Guidelines for Placement
There are seven (fill them in below)

42 Exposure sequence for film placement
Patient Preparation Make sure that you read over the procedure in your book Exposure sequence for film placement Make sure you understand what teeth should be present in what x-ray

43 Producing Full Mouth There is a whole procedure outline in your book for each tooth/teeth Be very familiar with each section

44 Bisecting Technique Based on the geometric principle of equally dividing a triangle Places film directly against the teeth to be radiographed, so teeth and film are not parallel but are at a right angle

45 Film holders are used rather then the XCP
Understand patient positioning Beam alignment

46 Bite Wing Technique Shows the crowns and interproximal areas of max and mand teeth and the areas of the crestal bone Basic principles Placed parallel to the crowns of upper and lower Stabilized when the patient bites on the tab or holder Central beam is directed through contacts of teeth using +10 degrees vertical angulation

47 Occlusal Technique Take an x-ray of entire maxillary or entire mandibular arch at one time

48 Mounting Radiographs You need to be able to recognize anatomic landmarks If I showed you an x-ray with a Nutrient canal and Lingual foramen on it, would you be able to tell me that this is a mandibular anterior x-ray????

49 Guidelines for Mounting
Handle films by the edges Learn normal anatomy Label and date film mount before mounting films Mount immediately Use clean dry hands Use order of teeth to distinguish right from left

50 cont Use definite order for mounting
Mount bite-wings with the curve of Spee upward (makes a smile)

51 Chapter 42 Extraoral and Digital Radiography
Extraoral—large areas of skull or jaw must be examined (outside of mouth) Panoramic—entire dentition and structures on single fillm Why would they be used? What type of equipment is used What would be some errors that could take place

52 Advantages and Disadvantages
Field size Ease of use Patient acceptance Less radiation Image sharpness Focal trough limitations Distoration Cost of equipment

53 Cephalometric films Takes side view of skull
Used mostly in orthodontics and surgery

54 Digital Radiography Advances in computers have made this the way of the future Filmless Records images What is the basic concept? Understand types of digital imaging

55 Advantages and Disadvantages
Gray-scale resolution Reduced radiation exposure to the patient Faster viewing of images Lower equipment and film costs Patient education Initial set-up costs Quality of images Sensor size Infection control

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