Radiology
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Presentation Transcript
Radiology Chapter 38 Foundations of Radiology, Radiographic Equipment, and Radiologic Safety
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
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
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
Types of Radiation • Primary • 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
Characteristics of Radiograph Beam • Quality, quantity and intensity of beam • Determine contrast, density and image detail (good x-ray)
Radiolucent and Radiopaque Characteristics • Radiolucent • Structures that radiation can pass through easily (dark) • Such as: • Radiopaque • Structures that radiation cannot pass through easily (light) • Such as:
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)
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
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
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
Geometric cont • Distoration • Disproportional change in size of images • Too much or too little vertical angulation • Magnification • Proportional enlargement of radiographic image
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
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
Effects cont. • Critical Organs • Skin—seen as reddening or erythema • Thyroid gland—(how do you protect) • Lens of eye—can cause cataracts • Bone Marrow--leukemia
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
Maximum Permissible Dose Occupation persons = 5.0 rem per year Non-occupation persons = 500 mrem per year
Radiation Safety • Background radiation—comes from natural sources • Protective devices • Aluminum filtration ? • Collimator ? • Position Indicator device ?
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?
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
Safety • Equipment monitoring • What are the rules What is the ALARA concept?
Chapter 39Dental Film and Processing Radiographs • What is a film holder ? • Explain some of the few holding systems that are available
Dental Film • Understand the following • Film composition • Latent image • Film speed
Intraoral Film • Understand the following • Film 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)
Extraoral film • Film packaging ? • Film cassette ? • Intensifying screen ?
How and where do you store film ? • If you were duplicating film what equipment would be needed?
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
Errors • Fully understand the possible errors that can take place while processing films • How would you correct or prevent these errors
Chapter 40Legal Issues, Quality Assurance, and Infection Control • Quality assurance • Regular testing to detect equipment malfunctions, planned monitoring and scheduled maintenance
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
Cont • Patient records • Patient Refusal • Patient Education (Understand all of the above)
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
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
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
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.
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
Chapter 41Intraoral Radiography • Steps to quality radiographs • Placement • Exposure • Processing • = Quality radiographs
Full Mouth Series • Intra oral films • What type of x-rays are take in FMX • Two types of methods for exposing intra oral films
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
Guidelines for Placement • There are seven (fill them in below)
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
Producing Full Mouth • There is a whole procedure outline in your book for each tooth/teeth • Be very familiar with each section
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
Film holders are used rather then the XCP • Understand patient positioning • Beam alignment
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
Occlusal Technique • Take an x-ray of entire maxillary or entire mandibular arch at one time
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????
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
cont • Use definite order for mounting • Mount bite-wings with the curve of Spee upward (makes a smile)
