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19317 Quality AssuranceEDUCATIONAL OBJECTIVESUpon completing this chapter, the student will be able to:1. Dene the key terms listed at the beginning of the chapter.2. Discuss the following related to chairside technique:• Statethesignicanceofensuringthatallpersonnelaretrained properly and monitored regularly in exhibiting high levels of chairside competence.• Listtheresponsibilitiesthatthesupportivestais responsible for in maintaining a sound dental radiographic quality-assurance (QA) program as recommended by the American Academy of Oral and Maxillofacial Radiology (AAOMR).3. Discuss the following related to conventional radiography quality assurance, processing maintenance, and lm maintenance:• DescribetheQAconstituentsofmonitoringandmaintaining the x-ray units in a dental oce.• Discussthestepsthatthedentalprofessionalshouldtake in assuring that the processing techniques, equipment, and darkroom are optimally monitored and maintained.• Explaintheproperstoragefordentalradiographiclmand the importance of checking the expiration date for a box of lm.4. Discuss the following related to extraoral radiography, lead contamination, and digital sensor maintenance:• Describethestepsinassuringthepropermaintenanceof the cassettes and intensifying screens that are used for extraoral radiography.• Knowthemainsourcesofleadusedindentalradiography and the steps in preventing the harmful eectsofthissubstance.• Discussthestepsinmaintainingtheintegrityofthedigital sensors used in dental imaging.KEY TERMSAmerican Academy of Oral and Maxillofacial Radiology (AAOMR)calibration procedureCertied Radiation Equipment Safety Ocer (CRESO)darkroom maintenanceintra-oce peer reviewnormalizing devicequality-assurance (QA) programrecord keepingreference lmstep wedgeChairside TechniqueMaintaining high levels of chairside competence is the basis of any successful QA program. Using programs of self-evaluation, intra-oce peer review, and continuing education, superior levels of chairside technique can be attained and retained, thus keeping retakes to a minimum. One should remember that every retake that is needed doubles the radiation to the patient for that image. e ultimate goal in dental radiography is to produce the most diagnostic radiographs with the least amount of radiation exposure to the patient. e criteria for radiographs given in Chapter 9 should be followed at all times. e task of reviewing radiographs can be assigned to any member of IntroductionOne of the most important protocols in a dental oce is a quality-assurance (QA) program. QA is a plan of action, concern, and responsibility to ensure that the x-ray images obtained in a dental oce are of the highest quality, with minimal exposure to patients and dental personnel and resulting in the maximum diagnostic yield. An eective QA policy and administrative protocol that monitors the use of radiation in a dental oce is the shared responsibility of all members of the dental team. QA programs fall into the following categories: chairside technique, monitoring of conventional and digital x-ray equipment, and darkroom equipment and procedures. 194 CHAPTER 17 Quality Assuranceconrm that the radiographic equipment is functioning properly in producing consistently diagnostically accept-able radiographic images. e AAOMR has published an outline of preventive procedures for radiographic systems. In some areas, a health physicist or a Certied Radiation Equipment Safety Ocer (CRESO) would perform the inspection. e type of inspection and calibration included in this group are checks on kilovoltage, milliamperage, output, timer accuracy, tube head stability, and x-ray beam alignment (Fig. 17.1).e dental professional is responsible for maintaining the x-ray equipment and should report any equipment malfunctions, including tube head drift, head leakage, timing issues, and images that consistently do not meet diagnostically acceptable standards as a result of problems with the x-ray equipment.Conventional Radiography Quality AssuranceProcessing TechniqueAn eective QA policy for processing lms and the dark-room is the shared responsibility of all dental professionals in the facility. Regardless of whether manual or automatic processing is used, a QA program in the darkroom is as important as and much easier to conduct than monitoring of the x-ray machine. First, for a darkroom QA program to be eective, the darkroom must be a darkroom and nothing else. e room should be a dedicated space rather than a place for general storage or for use as a dental laboratory.At least monthly, and depending on the workload, the dental professional should check the safelighting, light-tightness, and accuracy of the timer and thermometer in the darkroom. If the processing tank lid is missing or the thermometer is broken, it should be noted and ordered. Charts showing when the various QA procedures were performed and by whom should be on the wall or in a dark-room logbook (Fig. 17.2). e dental professional should monitor the cleanliness of the countertops, the condition of the lm hangers and clips, and the level and strength of the processing solutions.As mentioned in Chapter 11, the test used to conrm the reliability of the safelight is known as the “coin test.” is test is used to ensure that the safelight is acceptable for processing conventional lm without exposing the lm to unacceptable lightning, resulting in fogging or darkening of the radiographic image.e chemical strength and level of solutions in both manual tanks and automatic processors must be monitored on a daily basis. is is the most critical part of a QA program. Processing solutions should be changed every 2 to 3 weeks depending on usage. Both manual tanks and automatic processors should be cleaned at least weekly depending on the workload of the oce sta. ere are better ways to determine when solutions should be changed than by just using the calendar or “eyeballing.”An easy way to obtain a rough estimate of solution strength in a dental oce is to compare it with a standard or reference lm (Fig. 17.3). A processed periapical lm In most dental practices, the supportive sta is most likely to be responsible for certain procedures, which the American Academy of Oral and Maxillofacial Radiology (AAOMR) groups into the following categories:• Conductingproperchairsidetechnique• Makingsurethat all dentalx-ray unitsaremaintainedproperly and functioning optimally• Properlystoringandhandlingall lms, digital sensors,cassettes, screens, grids, and processing chemicals• Posting current technique charts, including a time-temperature chart for processing, x-ray exposure factors, x-ray equipment measurements, and darkroom mainte-nance schedules• Accuraterecord keeping of lms processed, mounted, and led• Maintainingproperconditionsofprocessingtanksandautomatic processors• Maintaining optimal darkroom conditions by periodicchecks for light-tightness and adequacy of safelighting, cleanliness procedures, and temperature control of solutions• Maintaining the conditions of protective devices, suchas lead aprons, thyroid collars, barriers, and receptor-holding devicesAlso, it is the responsibility of the dental team to enforce the oce infection control policy, because it concerns chairside technique and lm processing.Dental X-Ray Machine MaintenanceX-ray machines must be monitored and inspected on a regular basis. ere are state and local agencies that provide inspection services as a component of their licensing and registration processes. Dental x-ray machines should be adjusted for accuracy at regular intervals. is action is referred to as a calibration procedure. X-ray machine calibration is performed by a competent technician to HELPFUL HINTThe remedy for an exposure error is usually the reverse of the cause. When an image is not diagnostically acceptable, the radiographer is responsible for troubleshooting the cause before retaking the image so that the error is not repeated. As Albert Einstein said, “The denition of insanity is doing the same thing over and over again and expecting different results.” Although this behavior may not categorize the operator as actually being insane, it will add to the radiation burden of the patient unnecessarily.the oce sta. e ability to accept criticism and perform self-criticism is an essential trait that must be developed. Each member of the dental team should ask for help and supervision instead of constantly repeating the same error. If a dental professional does not seek self-improvement, eventually a radiograph that is not diagnostic can become inappropriately acceptable. is type of imaging is useless and does the patient a disservice if committed repeatedly. 195CHAPTER 17 Quality Assurancelm is placed in a slot, and the measured densities are moved until a visual match of densities is achieved. If the test densities are too light, the solutions are too weak or too cold. If the densities are too dark, the solutions are too concentrated or too warm. Either of these situations is unacceptable, and processing cannot begin until conditions are optimized. e strength of the xer can also be gauged by noting the time needed to clear lms. Fresh, full-strength xer clears lms in 2 to 3 minutes. If clearing requires more than 4 minutes, the xing solution is weak and should be changed. It follows that usually developer and xer solu-tions will require changing or replenishing at the same time.of ideal density should be kept taped to the darkroom viewbox for comparison of densities of the lms that are processed daily. A lessening of lm density in the processed lm indicates a weakened solution and signals the need for a solution change. Do not wait until the lms lose their diagnostic usefulness to change the processing solutions. A better and more scientically controlled way to make a test exposure is to use a step wedge at the beginning of each work day. is test exposure is done with a step wedge or a predetermined density (Fig. 17.4). e lm is then processed and compared with standard lm densities. With the normalizing device shown in Fig. 17.5, the processed NEW YORK UNIVERSITY COLLEGE OF DENTISTRYRADIOLOGY QUALITY-ASSURANCE PROGRAMType of Unit:Location:kVp:mA:HVL: mm of AIFFD: inAverage Exposure Time (F-speed film) impulsesOutput (Emission Rate) mR/sCalibration Date Performed By: EXPOSURES WITH EKTASPEED FILMSMaxillary Anteriors Mandibular AnteriorsMaxillary Premolars Mandibular PremolarsMaxillary Molars Mandibular Molars Bitewings Occlusals Calculation of Facial Dose: DO NOT REMOVE THIS NOTICEAdd up all exposure timesDivide by 60Multiply by Emission Rate• Figure 17.1 Form used to monitor dental x-ray machines. 196 CHAPTER 17 Quality Assurance• Figure 17.5 Dental radiographic quality control device. The radio-graph is exposed under the copper and processed as usual. The resulting radiograph is inserted into the device and compared to the 7-density lm strip. If it is too light or too dark, possible causes and corrections are indicated. (Courtesy Xray Quality Control, Vail, CO.)Quality ControlRadiographic Processing SolutionLocationWeek Of MondayTuesdayWednesday ThursdayFridayMaintenanceDone by: Done by: Done by: Done by: Done by:Maintenance Maintenance Maintenance MaintenanceMaintenanceDone by: Done by: Done by: Done by: Done by:Maintenance Maintenance Maintenance MaintenanceMaintenanceDone by: Done by: Done by: Done by: Done by:Maintenance Maintenance Maintenance MaintenanceMaintenanceDone by: Done by: Done by: Done by: Done by:Maintenance Maintenance Maintenance MaintenanceR = ReplenishedCH = Changed SolutionMonth/Year• Figure 17.2 Chart used to monitor processing solutions in the darkroom. • Figure 17.3 Reference lm used to check solution strength by comparing densities. • Figure 17.4 Step wedge and lm before exposure. 197CHAPTER 17 Quality Assurancethe stored intraoral lm. is powder is about 80% lead and may be ingested by patients and operators. Fortunately, most dental oces currently store lm out of the operatory or use stable metal dispensers. It is also important that all dental personnel appropriately dispose of the lead foil that is removed from the lm packet in the dental oce and that the proper agency conscates it from the oce.Digital Radiography Quality AssuranceDigital Sensor Maintenancee digital sensors used with direct and indirect digital radiography must be handled with proper care and main-tained in optimum condition. ese eorts ensure that they provide reliable service and adhere to infection control regulations.e sensors used with direct digital radiography should be wiped with a disinfectant along with the sensor cable and then the sensor should also be covered with barrier sheaths before use to prevent sensor contamination. e sensor cable is carefully uncoiled, and the operator is expected to remove all tangles and sharp bends from the cable. e operator is encouraged not to soak the sensor in sterile solution or place it in an autoclave. e sensor or cable should not be clamped with a hemostat. e dental professional should avoid stepping on or rolling over the cable with the operator chair. e sensor cable is to be gently coiled and placed in a protective case after use. e phosphor plates used with indirect digital radiography should also be covered with an infection-control barrier before use. ey are also not to be submerged in cold sterilizing solutions or autoclaved. All sensors are to be handled very carefully, and all eort should be made to maintain them in optimum condition to withstand years of successful daily use.Chapter Summary• AQAprogramisaplanofaction,concern,andresponsi-bility to ensure that the x-ray images obtained in a dental oce are of the highest quality, with minimal exposure to the patients and dental personnel, which consequently results in the maximum diagnostic yield.• AQAprogramisinstitutedinadentalfacilitytomakecertain that all equipment is functioning optimally, including the constituents of radiographic processing, exposure, digital radiography, and that the elimination of hazardous material (lead) is addressed accordingly.• eAAOMRsuggeststhatawell-designedQAprotocolin a dental oce should include regular monitoring and testing of a dental facility’s chairside techniques, x-ray units, lms, digital sensors, cassettes, intensifying screens, grids, processing equipment, and processing chemicals.Film MaintenanceUnexposed and unprocessed lms, as well as solutions, should be stored in a cool, dry location. ey never should be stored in an unventilated room near the heating system. Films should be stored at temperatures of 50° F to 70° F and be-tween 40% and 60% relative humidity. Films should be used before their expiration date, and lm boxes should be clear-ly marked. Older boxes should be placed on the front of the shelf in keeping with the “longest in, rst out” rule.Extraoral Radiographye screens and cassettes that are used to produce diag-nostic images in extraoral radiography should be checked and maintained on a regular schedule. e intensifying screens inside the extraoral cassettes should be cleaned with appropriate manufacturers’ suggested solutions at least once a month. After cleaning the intensifying screens, the dental sta member responsible for maintaining them should apply an antistatic solution to the screens. If an intensifying screen is scratched, it must be replaced, because scratches and dirt on the screens cause unacceptable artifacts on the resultant radiographic images.Lead ContaminationLead contamination has been determined as being haz-ardous to humans and to the environment. One of the potential sources of lead exposure in the dental oce that is not currently as common as it was in the past is the use of lead-lined boxes for lm storage. Unexposed lm was previously kept in the operatory in lead-lined boxes. Over time, the lead used to line the shielded boxes may oxidize and produce a white lead powder that may contaminate Chapter Review QuestionsMultiple Choice1. A plan of action, concern, and responsibility to ensure that radiographic images used in dentistry for diagnosis and treatment are of the optimum quality is known as: a. A reference lm b. A normalizing device c. A QA program d. Universal precautions e. e ALARA principle2. Which of the following steps should be taken when ensuring the proper care and maintenance of digital sensors? a. e sensors should not be autoclaved. b. e sensors should be covered with a barrier sheath. c. e sensors cabled should not be stepped on. d. e sensor cable should be carefully uncoiled. e. All of the above. 198 CHAPTER 17 Quality AssuranceCritical Thinking Exercise1. You have recently been designated as the QA manager in your dental facility. Your specic responsibilities are to make sure that the x-ray units and processing equipment are functioning properly. Discuss the steps you would take in accomplishing this assignment. Be sure to include the following in your discussion: a. A description of your plans to enlist a health physicist or a CRESO to perform the necessary calibration procedures and what they will specically be checking for. b. A list of the equipment malfunctions that should be reported to the dental oce manager. c. A schedule for checking the safelighting, light-tightness, and accuracy of the timer and thermometer in the darkroom. d. e test for conrming the reliability of the safelight in the darkroom. e. ree ways for checking the strength of the processing solutions.BibliographyAmerican Dental Association Council on Scientic Aairs: An update on radiographic practices: information and recommendations, J Am Dent Assoc 132:234–238, 2001.Eastman Kodak Co: Quality assurance in dental radiography, Roches-ter, NY, 1999, Health Science Division.Iannucci JM, Howerton LJ: Dental radiography: Principles and tech-niques, ed 5, St Louis, MO, 2016, Elsevier Saunders.Recommendations for quality assurance in dental radiography, Oral Surg Oral Med Oral Pathol 55:421–426, 1983.3. ___________________ contamination has been determined as being hazardous to humans and to the environment. a. Phosphor b. Metallic c. Lead d. Processing solution e. Step wedge4. After intensifying screens are thoroughly cleaned with the appropriate solution, they should be treated with: a. A solution containing alcohol b. An anti-contaminant c. An anti-radioactive solution d. An antistatic solution e. A soluble solution5. A better and more scientically controlled way to ensure the strength of the processing solutions is to: a. Use a step wedge at the beginning of each work day b. Add a replenishing solution c. Test the half-value layer (HVL) d. Empty the solutions every day e. Clean the processor roller daily