Radiology- ABGD Flashcards
Based on the ADA, what are the guidelines for prescribing xrays for a new, adult pt, adult recall with caries, and without caries
New adult: FMX (if evidence of generalized disease or hx of extensive tx) or pano and BWX and selected PAs
Adult Recall w/ caries: BWX Q6-18mo mo
Adult recall without caries: BWX Q24-36mo
What is the max permissible dose of rad per year for a pregnant pt?
5 mSv/year (151 E speed films)
What is the max permissible dose of rad per year for the average pt?
50 mSv/year
What is the “safe zone” when taking xrays?
6 ft from pt and xray beam.
stand 90-135* to the central ray of the beam
What extraoral films can be utilized to see the following conditions: body of the mandible fx?
body of the mandible fracture- pano, towns
What extraoral films can be utilized to see the following conditions: neck of condyle fracture
neck of condyle fracture - reverse town, Submentovertex
What extraoral films can be utilized to see the following conditions: zygomatic arch fx
zygomatic arch fx- waters, sub mento vertex
What extraoral films can be utilized to see the following conditions: orbit fx?
orbit fx- ceph, water, PA ceph
What is this?
Tonsilloliths
what is this
Eagles syndrome if painful- calcified stylohyoid ligament
Sialolith
What is the error and how do you correct?
pt is too far forward
narrow blurred ant teeth
vertical distortion in the anterior
cause: anter teeth are infront of bite groove, position teeth in bitegroove
What is the error and how do you correct?
pt is too far back
wide ant teeth, condyles off image
superimposition of the spine
teeth not in focal trough
postion ant teeth in bite groove
check position of the certical light layer
What does kVp affect?
Increase kVp= decrease contrast
increase kVp= increase energy, penetration/quality
kilovolt peak in the tube voltage
high contrast = lower kVp = endo and caries. more black and white
What does mA affect?
mA is the tube current (milliamp)
increase mA = increase in # of electrons and darkness
What is the inverse law and how do you practice it?
doubling the distance from the xray source decreases the xray beam intensity by a factor of 4.
By making sure the staff is 6 ft away, it max safety
How does time of exposure affect the image?
double time = double # of photons = double dose
does NOT increase energy
digital sensors need less time
What kind of radiography system do you use and why?
dentrixdigital- xrayvision software
Rectangular collimation
Never less than E speed film type:
D= 0.081mS1
E= 0.033 mSv
Describe scatter?
defelction of xray photons through tissues and materials. Contributes to image degradation, loss of contrast and increase dose
Describe attenuation
An xray beam passes through the tissue, photons get absorbed, so there is less energy. Result is absorption and scatter
Describe absorption
tissues accept xray photon energy, which contributes to image contrast. increases dose to pt
Describe noise
appearance of uneven density in a uniformly exposed image.
localized variation in “speckle” or grainy image
How do mA, mAs, kVp, time, and distance affect density?
increases in all of them will increase the density except for distance.
Increase in distance decreases density
When someone refers to the darkness/blackness of an image what property are they referring to?
Density
too dark- excess
too light = insufficient
If your xray is too dense, what can you do to correct?
less: time, kVp, mA,
more distance
What is contrast
blacks and whites- less grays
ability od an imaging system to distinguish between different densities of objects
On your xray unit how can you control or adjust the contrast?
kVp
increase kVp= decrease contrast (more grey)
When would you want to use low kVp?
endo, caries
When would you use high kVp?
help visualize bone. good for perio and oral path eval
Why do xrays magnify? What is the clinical impact?
due to diverging xrays
long cone and use of collimators can decrease this impact clinically
max distance between the focal spot and sensor and minimizing distance between the object and the sensor will reduce magnification.
IO radiography magnify about 4% wile a pano’s magnify about 20
What is the long cone technique
use of paralleling device to direct the beam perpendicular to the long axis of the tooth which will minimize the distortion/magnification
Examples of quality control that be implemented in your practice?
use of a radiation health survey
*physical: mechanical, electrical, including tube drift/movement
*beam quality: validates the operating kVp
*tube potential: kVp, timer, exposure vs normal
*radiation dosimetry: scatter, suvery, leakage, within room any time facilities change
Clinician is responsible for day to day operations and to assess clinical value and proper settings.
1, 2, 3
- maxillary sinus
- pterygoid max fissure
- pterygoid plate
4, 5, 6
- hamulus
5, zygomatic arch - articular eminence
789
- zygomaticotemporal suture
8, zygomatic process - EAM
10,11,12
10.mastpod process
11: middle cranial fossa
12.lateral boarder of the orbit
13, 14, 15
- infraorbital ridge
- infraorbital forame
- infraorbital canal
16, 17, 18
- nasal fossa
- nasal septum
18: ant nasal spine
16, 17, 18
- infraorbital ridge
- infraorbital forame
- infraorbital canal
19, 20, 21
19: inferior concha
20: Incisive foramen
21: hard palate
22, 23, 24, 25
- max tuberocity
23: condyle
24: coronoid process
25: sigmoid notch
26, 27, 28, 29
26: mesial sigmoid depression
27:styloid process
28: spine- cervical vertebra
29: external oblique ridge
30, 31, 32, 33, 34
30: mand canal
31: mandibular foramen
32: lingula
33:mental foramen
34: submand gland fossa
35, 36, 37, 38, 39, 40
35: internal oblique ridge
36: mental fossa
37: mental ridges
38: genial tubercles
39: hyoid
40: tongue
41, 42, 43, 44,
41: soft palate
42: uvula
43: post pharyngeal wall
44: ear lobe
45, 46, 47
45: glossopharyngeal space
46: nasopharyngeal air space
47: palatoglossal sair space
