Radiology revision notes Flashcards
Tube head components
filament - cathode, negativel y chaged, step down trasnformer, low voltage and high current
targert - anode - postively charges - converst electrons to photons
target surround - copper heat conductor
spacer - beam aiming device - focus to skin distance
colliamator - lead, fewer rejects, reduces doses and improves quality
evacapeted glass envelope
filtration - aliuminum - allows high energy electrons through
Non epithelium cysts
solitary bone cysts
stafne bone cavity
Stafne bne canvity
aymptomatic
occurs in the mandible at the angle just below the inferior dental nerve canal
radiolucnecy, round oval and well defined
Solitary bone cysts
occurs in premolar region in mandible
painless and symptomatic
radioloucyent with well defined scalloped margins, can resolve without treatment
non odontogenic cysts
nasoplataine cyst - occurs at the naso palatine duct area, asymptomatic
remanacy of nasopalatine duct
males more than females
enlarged swelling nin anterior region of apalte
well defined and rond/ heart shapaed
lined by non stratified squamous epithelim and respiratory/cuboidal epithelium
Odontogenic inflammatory cysts
radicular cysts
residualr cysts
inflammataory collaiteral cysts - aradental and mandibular buccal bifurcation cysts
Residualr cysts
a ondotongenic inflammaorty cyst that remains after the removal of a tooth in the jaw
Radiuclar cysts
most commmon in anon vital tooth
inflammation of apical - casuing apical periodontitis
mainly maxillar and normal lateral incosors
watery straw fluid colour or semi solid broownish
Radicular cysts
epithelial rests of malassez from root sheath of hertwig
Histopathology of radicular cysts
lining is non keratinsied squamous epithelium lining
deposits of cholesterol and granualtion tissue
vascular capsule
inflammotry infiltrate
Paradental cysts
associated with pe erupting 3rd molar in manidble
normally assocaited with repeated cases of peroconritits
well defined radioloucy at the neck of tooth andcornoal third of root
cysts distince from follicular space
Manidbular buccal bifurcation cysts
childhood and eruption of 1st and 2nd molars
depp perio pockets present and tooth tilted buccally
squamous cell lining present like in a radiuclar cysts
inflammatory colateral cysts
occur in vital teeth of pe or erupting teeth usually buccally
non ondontogenic cysts
nasopaltine cyst
nasolabial cysts
median cyst
globulo maxiallry cyst
Developmental odontogenic cysts
dtergerious cysts
odontogenic keratocytes
calcifiying odontogenic cyss
lateral periodontal cysts
glandular cysts
eruption cysts
Basal naevus syndrome
Gingival cysts
Eruption cysts
occur on an area of soft tissue mass over where an erupting tooth is erupting into place
mainly decidous incisors and permanent molars
tx - surgical excision
Dentigerous cysts
arised from the reduced enamel epithelium
a cyst which encaptuales an uerupted or partial erupted tooth and attaches to cej
round avoid appearaced
most common 3rd molars, maxiallry canines maxially 8’s and then lower 2nd premolars
males more than females
free from inflammation
non kertanised epitheium, thinand regular
tx - enculeation with asscoaited tooth or malsuprisation if large
Lateral periodontal cysts
uniloclualr
lateral surface of root of a tooththat has erupted
canines and premolars in lower and anterior in upper
tx - enulceation
Gingival cysts
most comonly occur before <3months in neonates
children white kerathosis seen = bohn’s nodules or epistein pearls
adults - rae, thin bluish swelling within attached ging
Tx - excional to carry out biopsy
Calcifying cysts
anterior jaw
<40years
radiopque fleck due to calficied material present
ghost cells present within capsule casuing calcification
tx - enucleation as recurrence rae
Glandular cysts
mandible or anterior maxialla
assocaited with roots of tooth, root resoprtion adn toth dispalcement commone
recurrence rate high after enulceation
well defined scalooped margins
Odontogenic keratocysts
arises from the rests of serres in the dental lamina remnants
high risk of recurrence
no inflammation
caspule contains fibrous tissue
can contain daught cells
Basal cell neavus syndrome
autoosomal domoina
multiple odontogenic keratocysts preent and basal celll carcinoma
abnormalities of ca and po4
facial - mandibular prognthasmim, frontal and temporaorital bossing, hpertelorism
Contributes to radiation dose
cosmic rays
medical rays
gamma radation
radioactive radon gas from ground
radiiology lesilation
ionisig radaition regulation 2017
ionising radiation medical exposure regulation 2017 (just for patient saftety only)
annual radiation dise
2.7mSv
Doses for xray fils
PA = 4milliSv
ceph = 14mill Sv
panoral = 20 milli sv
cbct = 50-100milli sv
Pricnicples of radiation
dose limitation
justification
ALARP
Roles in IRR17
operator - prson who carries out taking the xray
referrer - person who refers the pt for the xray indiating clincal reasoning to allow practioner to justify exam
practioner
person who ensures as low as possible for patient and justifaction to be given
Radiation protection advisoer - expert report on ensure ioningig radiation regulation re followed, and adviced
radiation protection superisor - ensure that legal requirments and good practice are followed
medical physic expers - can provide info on the physics behind the radiation exposure to pt and taken the xrays
Faults to film
black film = film bent
brown spots - inaqaute fixing time
crazed pattern - dried too quickyl over heat source
fading image - inadequate fixing time
faint image -d eveloper solution too weak, temp too low
black spots - splashing with fixer before developer
crystal present - insufiifcent washing after fixing
Cone cutting why-
incorrect assembly of the receptor holder
incorrect allignment of receptor and tube head
incorrect orietation of rectangular collimator
Film speed
the speed required to allow enough xray exposure to produce an image
depends on the number of hallide crystals
the larger the hallide crysal the faster film speed but pooer image quality
Stages of film processing
developing - converts senstisited crystal to silver pataches
washing - removes any residual fixer solution
developing - removes non senstised crystal and hardens emulsion
washing - removes any resifual fixer solution
drying - removes any mositure and water content
Adv./dis of digital films
advatanges - can sotres many on computer, easily trasnfereed, low exposure time, eaasy back up of images, no processing faults
dis - need speaclised computer for diagnositic reading which is expensive, poor pixel quality when printed out, potential loss of data, risk o fpixelation
CBCT vs CT
CBCT - cone shaped, does not require ionising radiatin, not great for soft tissue, pt standing up, quicker to take, low dose
CT - fan shaped, shows soft tissues better, higher dose, takes longer totake, pt horixzonta , requires ioodinsiing contrast to be used
MRI vs CT
MRI - shows soft tissue easily, has no radiation expsure, no contracts required
takes a long tim, clasutrpophia, metallic things in body, nosiy for pt
CT - requires ionisdaing radiation exposure, cntrast, more for tumours, blood vessels, flashing noise adn sound
quicker, small ring so reduced calasutrophbia
safety controlled area
2m a saftety ring around the pt where no person should go while the xray is being taken
Cervical burnout
a radiolucnecy that appears at the cervical area of a tooth due to just being dentine present at the cervical portion and mimics root caries
Faults
<90 degrees = elongates the tooth
>90 degrees = shortens the tooth
vertical/horizontal distortion - the pt moved
molars larger on one side = head rotated and bt not being symmertical on the bite peg
anterior area out of focus - pt too far back in the machine - canine behind guidance marker
posterior horizontally wider -pt roated in the machine
Ghost images
second image of something in the wrong place
higher due to negaative beaam angulation
radiopaque
can interfere with diagnosis
horizontally projected andmagnied
change in aterior - posterioer position - suually further forwards
Ghost image produced
the xray tube head starts posteriorl ad the rba is directed to the opposite tmj region, as it moves round when it gets to the premolar region the image is created from a more posterior region and therefore any ghost images are anterioly produced
higher placement as negative beam angualtion
radiopaque
interefers with diagnosis
horizotnoally maginifed and projected
tends to be more anterio-postieorr positioned
parallelin tech
the image receptor is heald parallel to the the long axis of the tooth
the xray beam is directd perpendicular to the long axis of tooth
the image is the same size
no coning off
no disotortiong
howver can cause divergent xray beaams and magnifcation due to distance between the xray recptior and tooth
use focus to skin distance at 20cm the ensure to help with divergent beams`
bisecting angle techingque
the angulation of the long axis of the tooth is determined
the xray receptor bisects at right angles to this
can be doen withoutxray holder
Curve of monsoon
affects vertical angulation
cusp tips of posterior in frontal plane
curve of sppe
natural curvature in dentitision when the cclusion vied in saggital plane
Reduce radiation to pt
rectangular collimator
f spped film
justifaction
alarp
focus to skin distance at 20cm
film holders and beam aiing device
incrase kvp
odontogenic tumours
arise from the remaining tooth tisuue cells that remain in the jaw
Ameloblastoma
epithelium only - odontogenic neoplasm
a soap bubble appearnce on xrays
occurs mainly in the posterio manidble
follicular - islands of epithelium
plexiform - single strands of epithelium
no internal capsule prsent so easily spreads and thereofre recurrence is high
islands contain stellate reticulum with on its perpihery columnasr cells
nuclia away from the basement mmebrane
abudentl cytoplasm
tx - enucleation with some removal of surrounding helahty tissue , cannot be radiotreated as does not work
calcifying epithelium odnotigenic tuours
epithelium only
benign epithelium tumour
occurs in posterior mandible
also called pindborg tumour
arreas of radioilucy mixed with calicification
pleomoprihc epithelium and calcification present
odontomes
epithelium and mesenchmye together
hamartomas - resemble local tooth tissue
complex - irregular mass of hard tissue - manidble posterior
compound - denticles in a sac - anterior maxillary
contain, ameloblasts, odontoblasts and cementoblasts and eventuallyhard tissue forms
failure of eruption of a nearby tooth
tx - surgical enulceation
Adenomatoid odontogenic tumour
epithelium only
asscoated with an impeded eruption
unilocular
haematroma
fisbour caspure surrounds anterior region f>m
Odontogenic myoxma
mesechnyme only
bening meschnyme tumour
no internal apsule or epithelium
manidble common
multilocular soap like appearance
myoid tissue with stellate and fibrous tissue
tx - block resection
Cementoblastoma
meschenyme only
true neoplasm
occurs in vital teeth that are extruded or painful
radiodense suround by a radiolucent rimm
rooots of lower 1st molar common
PA of mandible
cysts and path
mandibular fractures
facial deformity
lateral ceph
pituatry foosa
facial fracture
sphenoid fossa
pituatry fossa
occipitomental view
cornal 1/3 fractures
middle 1/3 fractures
submentvertex
craniail pathology
zygomaticr arch fractures
