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