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59 Cards in this Set
- Front
- Back
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What does ALARA stand for?
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As Low As Reasonably Achievable
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Is there a specific level of radiation dose for exposed person?
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No depends not patient
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Maximum permissble dose MPD
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Maximum dose of ionizing radiation which in light of present knowledge will not be expected to produce any significant radiation effects in lifetime
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What is not counted toward maximal permissble dose?
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radiation necessary for medical or dental diagnostic purposes is not counted in the permissible amounts of radiation
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NCRP occupational dose limit of stochastic effects
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50 mSv
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NCRP occupational dose limit of deterministic effects
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Eye 150 mSv
skin 500 mSv |
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NCRP non occupational dose limit of stochastic effects
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5 mSv
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NCRP non occupational dose limit of deterministic effects
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50 mSv
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NCRP non occupational dose limit for embryo
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0.5 mSv/month
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NCRP limit for negligible dose
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0.01 mSv
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FMX D speed round equals how many days of background exposure
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18.8 days
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BWs 4 with D speed round equals how many days of background radiation
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4.8 days
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one pano equals how many bitewings
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one pano equals four bitewings
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Pano with Ca tungstate screen equals how many days of background radiation
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1 day
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Pano with Rare earth screens equal how many days of background radiation
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10 hours
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by how much does a rectangular BID reduce pts skin exposure
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60%
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By how much does a E speed film reduce exposure to pts skin compared to D speed?
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50% compared to D speed
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FMX F round film equals how many days of background radiation
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5 days
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4 BWs with F round film equals how many days of backgound radiation
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less than one day
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advantages of collimation
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reduced field of exposure and dose
decreased scattered radiation and film fog increases film quality skin surface exposed to less radiation |
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Recommendatins for using BID
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open ended lead lined
long BIDs (8-16) rectangular pointed cones not recommended |
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purpose of film holding devices
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improve film stability and eliminates pt holding films
provide external guide for BID alignment |
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what is the advantages of faster film speed?
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Reduces chance of pt movement during exposure
reduce pt exposure by 40-70% |
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recommended kVp
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70-90 kVp reduces somatic exposure
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who should wear a leaded protective apron and thyroid shield
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Every pt
it minimizes unnecessary radiation |
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radiation operator is potentially exposed to
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primary radiation
scatter radiation leakage radiation |
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sheilding
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means used to stop unnecessary radiation
includes lead barriers,safe distance, or structures |
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most effective way of preventing scatter radiation exposure
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Shielding
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Ways an operator protects herself from radiation
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stand behind barrier
never stand in primary beam never hold film in pt mouth never hold tube head during exposure |
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How should operator stay protected if there is no barrier/shield?
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position and distance stand at least 6 feet away and 90 135 degrees from primary beam
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what is needed for film mounting and viewing?
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opaque film mounts
masked view box magnifying glass subdued environmental lighting |
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quality assurance
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steps that are taken to make sure that a dental office will make high quality x rays w/ max diagnostic info while minimizing radiation exposure to pt and staff
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benefits of quality assurance
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improve diagnosis
reduced radiation exposure fewer retakes time saving cost saving compliance w/state and federal regulations |
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2 categories of quality assurance
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1. quality control
2. quality administration |
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quality control
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test the performance of:
xray unit film processing image receptors lead shields film cassettes darkroom use logs,dates,results, and corrective actions |
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quality administration
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the managment aspect
assign responsibilities determine optimum testing frequency provide training eval test results eval correct actions and revision |
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with quality monitoring procedures what should be done annually
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calibrate the xray machine
check lead aprons and thyroid collars for cracks |
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with quality monitoring procedures what should be done monthly
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cleant intensifying screens and cassettes
check viewing conditions and boxes perform safelight coin test check exposure charts are posted by each machine |
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with quality monitoring procedures what should be done daily
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clean darkroom/keep it dry
perfor prcessor quality cntrl monitor quality radiographs fill out radiology retake log replenish processing slns check temp and time |
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safelight in darkroom
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15 watt bulb at least 4 ft away
kodak GBX 2 for 5-8 min no unsafe illumination test safe lt with coin test |
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when shoud safelights be replaced?
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if used for 12 hrs/per replace every 2 yrs
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with manual processing, when should sln be changed?
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every 15 days and at each change scrub and rinse the tanks
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2 kinds of automatic processing
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1. ready to use
2. concentrated (mix w/water) |
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how is automatic procssor cleaned?
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warm up processor and run cleaning film (8x10 cleanup flim) removes dirt and gelatin from rollers
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how to avoid processing errors
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clean processor regularly
replenish slns daily check time and timp of processor daily perform quality control every morning after replenishment and warm up |
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what do hi temps do to unexposed flm?
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decrease contrast and increase fog
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ideal temp and humidity of film
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50-70F and 30-50% humidity
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what does poor screen film contact cause?
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fuzzy image
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quality control of intensifying screems
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inspected for worn or stained areas/ scratches
specks of dirt absorb lt and cause specks on film clean it everday, dry with cotton. leave cassette open to dry aply antistatic sln |
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When are xray machine test done? By whom? what do they check?
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done yearly by technologist from radiation safety office
checks the following: xray outpur mA and timer xray machine quality kVp focal spot and size collimator and beam alignment stability of tube head |
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what is needed of operator to take dental radiographs?
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proper training
certification radiation safety course |
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do pts own radiographs?
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no. when pt pays for radiographs they are paying for dentists abilty to interpret radiograpshs and arrive at diagnostice opinion based on xray and clinical findings
the dentist legally owns the xray but pts can have a copy |
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greatest protection against claim of negligence
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radiographs
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common cause of malpractice suits
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failure of dentist to use xray in diagnosis of cases involving pain or swelling
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what if pt refuses radiographs?
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note it in pts chart and have pt sign it
dentist can offer to take radiographs at no cost to pt or do not treat the pt |
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why should inferior xrays be retaken?
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will be no use of evidence
reflection of dentists ability as a practioner and could cause irreparabel harm to reputatioin |
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when should dr prescribe xray/
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only after clinical exam
order xrays only that help diagnosis |
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selection criteria for xrays
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pts age
medical/dental history phyxical signs exposure should be reasonable |
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2 situations that mandate a xray
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1. clincal evidence of abnormality
2. hi probablity of disease |
