quality assurance radiology e lec Flashcards
what is quality assurance
the planned and systematic exclusion of procedures to ensure high quality images of high diagnostic yield at min radiation dosage
why is important with quality assurance
getting it right the first time
procedures in place to get a high quality image
overall review with feedback from previous records
why do we do QA
reduces the necessity of retakes minimises radiation to patient minimise costs minimises inconvenience saves time
what is the no 4 core of knowledge
a person physically directing medical exposure is expected to have an acquired the principles of QA and quality control applied to both equip and technique
what is the purpose of QA
adequate diagnostic information
radiation doses need to be as low as possible
relevant statutory requirements
who should do it
named person responsoble for implementation the whole dental team radiation protection supervisor operator dental nurse
how should we do it
comprehensive programme
inexpensive
shouldn’t require infrequent verification and modification
formal records to be kept and frequency of checks to be defined
the aim of QA programme
written down common sense
what are the essential procedures
image quality patient dose and x ray equipment darkroom films and processing training audits
how is quality rated
prospective evaluation:
retrospective evaluation
what is prospective evaluation
ratings are assigned and recorded as viewed. analysis of results at intervals not greater than 6 months
retrospective evaluation
representative sample drawn at regular intervals and rated and recorded
analysis not greater than 6 month
rating of image quality
excellent
acceptable
unacceptable errors
what does it mean if an imagine quality is excellent
no errors of prep
exposure, positioning, processing or handling
what does an image quality mean if its acceptable
some errors but which do not detect from the diagnostic utility of the radiograph
what does an image quality mean if its unacceptable errors
render the radiograph diagnostically unacceptable
what is the issue with image quality
it is subjective eg one persons acceptable is another persons unacceptable
quality ratings should be kept with
any actions taken
what do we do if there is an unacceptable radiograph
record the date, nature of fault, known or suspected cause, number of repeat radiographs
what do we need to look at in regards to patient dose and x ray equipment
need to monitor patient dose
low as practicable- x ray must comply with standards
if the representative dose is higher than the diagnostic reference levels( DRL) and review needs to be carried out
routine surveillance
what is the equipment consist of
X ray set
image receptor
intensifying screens and cassettes
viewing boxes
the x ray set: electrical safety
must comply with the latest regulations including safe use of work equipment, and guidance on the provision and use of work equipment regulations 1998
who checks equipment
appropriately qualified person
what do we also need to write when we check equipment
records of maintenance checks
what tests to dental x ray equipment go under
routine tests
acceptance tests
critical examination
what is the critical examination test
legal responsibility of the installer but the legal person is advised to obtain it
also the installer must consult with the radiation protection adviser (RPA)
what does the installer need to consult the RPA about
in regards to nature, extent, and results of examination
what is the essential content of the critical examination
clear and unambiguous description of equipment and location acceptability of location evaluation of warning signals evaluation of exposure control sufficient radiation protection evaluation of safety systems
what statement needs to be given to the user
provided with adequate info about proper use, testing and maintenance
who is responsible of carrying out the the acceptance test
legal person
who needs to be consulted in the acceptance test
the RPA
what should the routine test values be compared against
baseline values
what in regards to dosage needs to be tested
if the equipment is operating within agreed parameters
and assessment of typical patient dose for comparison with DRL
how is the routine etch different
different emphasis
what does the routine test confirm
no significant change to equipment and location
what can we compare our previous results with
with our actual results of the routine test
which body analyses the results form the x ray
THE NRBP( national radiological protection board)
what does the image look like if you have poor contact
slightly blurry
what is included in the inventory of x ray equipment
name of manufacturer model number serial number year of manufacture year of installation
how are the errors categorised
- patient prep
- patient positioning
3 exposure
4 processing
5 film handling
what do we need to be aware of when taking x rays
patients jewellery- lip piercings necklace, earrings and glasses braces hair grips dentures
what patient errors can occur
cone cutting- can be an error with the patient, x ray tube or film holder
how should a bitewing be taken
should be the occlusal plane almost horizontal parallel with the long axis of the film
no more overlap of enamel than half the thickness of enamel
what is the percentage of errors if no film holders are used
28%
what is the percentage of errors if film holders are used
4%
what is the issue with panoramic positioning
very susceptible to patient positioning errors esp anteriors
what does it usually mean if we see black on an x ray
over exposure to radiation or light
what could be shown on the panoramic radiograph
a very obvious white shadowing in the central region due to slumping
what are the classes of malocclusion
class 1- normal incisal relationship- just slightly overlapping the lower incisor class 2- upper incisor have an increased overbite either anteroposteriorly or sup inferiorly class 3- the upper incisors are behind the lower incisors
what can the panoramic radiograph look like if the patient is moving their tongue
obvious black shadowing on the mandible and a white undulating shadow line
what is recommended when taking a panoramic
it is recommended to have the patient put their tongue on the roof of their mouth
what can we use for adequate panoramic positioning
bite block
chin rest
use light bean diaphragms-vertical and horizontal lights to help with positioning
where do light beam diaphragms help position
mid face
canine region
frankfort plane
what is the frankfort plane
a line from the tragus of the ear through the palpable bony infraorbital rim area and is parallel to the floor
what can go wrong with exposure factors
underexposure
overexposure
double exposure]
what exposure factors are under our control
depends on machine and technique
kV
time
mA
what factor can we control in a panoramic
time
what should you be given when you have an intra oral set installed
should be given typical exposure values eg from lower molar PA
and you should extrapolate
what can you work out from the typical exposure values given
extrapolate
list of typical exposure values for different techniques, different sizes of patient and different areas of the mouth
what should viewing conditions be like
use proper viewing box- with analogue film
get rid of extraneous light
magnifying glass
x viewer- which blacks out extraneous light with a magnifying glass
how many % of dental practices used 50% greater exposure than was required due to faulty processing
30%
why can pale films develop
due to exhausted developer
over diluted developer
time too short
temperature too low
why can dark films develop
too long in the developer
concentration in the developer too much
temperature too high
developer contaminated by fixer
why do we get low contrast
overdevelopment underdevelopment fixer contamination inadequate fixation fixer exhaustion
who lays down the standards of QA films and processing
suppliers
what standards are laid down by suppliers in regards to QA films and processing
film speed expiry date storage conditions processing conditions frequency of changing solutions cleaning instructions for automatic processors
what are some QA procedures put in place
records to control film stock
records to control and validate chemical changes
cleaning procedures for automatic processes
how do you monitor chemicals
expose test object( standard distance and time)
developed in new chemical
used as reference
at regular intervals expose new film under same conditions
compare with reference
what can you use as a test object
pre prepared strips
step wedge
teeth
what do we need to be careful of when taking a panoramic but in regards to gloves
the talc from our gloves can transfer on the film when we are adjusting it and leave finger print marks on the radiograph
what are crimp marks
semi lunar dark marks which are due to bending of the films
how are you meant to store sheet film
upright as if something presses on the film it can result in static electricity showing up on the film
what do we need to do for QA for darkrooms processing
routine tests for light tightness
safelights
checks at least every year
keep a log
how do you test for light tightness
the coin test
put a coin on a exposed film- sensitisies the emulsion and left out with the safelight
and the film processed and see if you can see the outline of the coin- if you see the outline it is not safe
what should intensifying screen be cleaned with
a lint free cloth and a proprietary cleaner
what should be kept in the radiation protection files
QA of working procedures local rules legal persons procedures procedural and operational elements procedures not directly linked to x ray equipment
what should the procedure log have
the existence of local rules
record each time modified
intervals not exceeding 12 months
