RAD L2 - How to take radiographs Flashcards
what is a radiograph
record of image produced by transmission of x-rays through an object
what is radiology
interpretation of radiographic image
what do you need to produce a radiographic image
patient x ray machine image receptors film holder operator processing facility reading facility
what are the main 2 types of radiograph
single plane
multi-planar
what are the 2 types of single plane radiographs
intra + extra oral
what are 3 types of intra oral single plane radiographs
peri-apical
bitewing
occlusal
what are 3 types of extra oral single plane radiographs
panoramic tomogram
lateral Ceph.
lateral oblique
what is 1 example of multiplanar radiograph
CBCT - cone beam computed tomography
how would you ideally take a radiograph
- tooth + sensor close as possible
- long axis of tooth + sensor/film should be parallel
- x ray beam positioned so meets tooth + sensor at 90°
- position should be reproducible
what problems can occur when taking a radiograph
- teeth lie within bone - impossible to accurately determine root direction
- multi-rooted teeth
- anatomical structure (palate) prevent direct contact without bending receptor
when is periapical radiographs done and how should they be taken
shows entire tooth + surrounding structures
should demonstrate 2-3mm bone all around apex of tooth
what are 2 methods of take periapical radiograph
parallelling technique
bisecting angle technique
why is paralleling technique preferred over bisecting angle tech when taking periapical radiographs
accurate + reproducible
reduction of radiation dose
use positioning aids
describe the paralleling technique for periapical radiographs
- sensor placed into beam aiming device
- positioned so sensor parallel to long axis of tooth
- x ray tube angled perpendicular to sensor
- reproducible image made
Parallel X-ray beam meeting both tooth and image receptor at right angles (perpendicular) both vertically & horizontally w/ tooth & image receptor parallel to e/o
describe the bisecting angle technique for periapical radiographs
- place sensor close to tooth as possible without bending it
- angle formed between long axis of tooth + long axis of sensor is estimated
- x ray tube positioned at 90° + central beam aimed at tooth apex
what indications would you see that would tell you to take a periapcial radiograph
- apical infection/inflammation
- periodontal status
- trauma to teeth + associated alveolar bone
- presence + position of un erupted teeth
- assess root morphology prior extraction
- endodontic
- evaluation of apical cysts + lesions within alveolar bone
- eval implants post operation
- pre + post operative of apical surgery
what is occlusal radiography
radiographs where image receptor is placed in occlusal plane
what are 2 types of occlusal radiography
maxillary
mandibular
what are 2 types of maxillary occlusal radiography
upper standard occlusal
upper oblique occlusal
what indications would you see that would tell you to take a occlusal radiograph
- periapical assessment of teeth
- detect presence of pathology
- parallax for unerupted teeth
- fractures of teeth/alveolar bone
- assess of roots displaced
why is it important to give a patient a thyroid collar when doing upper standard/oblique occlusal radiograph
to protect thyroid - sensitive
what are the 3 types of mandibular occlusal radiographs
lower 90° occlusal (true occlusal)
lower 45° occlusal
lower oblique occlusal
what indications are there to know when to use a mandibular occlusal radiograph
- Presence of radiopaque calculi in
submandibular salivary ducts - Buccolingual position on teeth/pathology
- Expansion caused by tumours/cysts
- Assess mandible width prior to implant placement
would you use a thyroid collar for lower occlusal radiograph
no
it obstruct + affect the image
what is 1 type of extraoral radiography
panoramic
what are some disadvantages of using extra oral panoramic radiography
- Image Quality
- Operator dependant/ patient dependent
- Ghost images and superimposition
- ↑ Dose needed
- Magnification
what are some indication that would prompt you to take a extra oral panoramic radiograph
- 3rd molar assessment prior to extraction
- Orthodontics
- Mandibular fractures
- TMJ problems (changes in
occlusion/trauma/change in range of motion) - Multiple extractions
- Bony lesions/unerupted tooth which cannot be fully visualised on intraoral images
- In the case of a grossly neglected mouth
explain the extra oral panoramic tomography ( how radiograph is taken)
- The patient stands still whilst the tube head and sensor move around the patients head
- movement creates blurring of all structures that do not lie within the “focal
trough” or “focal plane” - Anything within plane is of acceptable
- Anything outside will appear blurred
- Positioning patient within focal trough critical = producing a panoramic
radiograph that is diagnostic
what is the focal trough - used in extra oral panoramic radiographs, + typically what shape is it and why
- 3d area within which structures are reasonably well defined on the final image.
- In panoramic machine, the focal trough is designed to be horseshoe shaped to correspond to
the shape of the dental arches.
how to position patient head within focal trough in extra oral panoramic radiograph
- Machine consists of patient-positional aids i.e.. chin rest, forehead rest, lateral head supports,
bite block. - Laser lights to help align patient correctly
- Mid sagittal plane should be vertical
- Frankfort plane (infraorbital rim to top of ear
canal) horizontal and parallel to the ground - Front incisors biting in the groove of bite block
- Machine adjusted to size of patient – using
callipers or “canine light”
what is a cephalometric x ray and when is it used
diagnostic radiograph used primarily for orthodontic treatment planning.
- image shows the relationship between teeth, jaw + profile, helpful for orthodontic
planning + realignment treatment
what are some indication that would prompt you to take a cephalometric radiograph
(Orthodontic/Orthognathic)
- Skeletal/soft tissue abnormalities
- Treatment planning
- Monitoring progress
- Assess results of treatment
what is the technique to use when taking a cephalometric radiograph
- Patient positioned in cephalostat with mid
sagittal plane vertical and Frankfort plane
horizontal - teeth should be in occlusion
- Head immobilised with ear rods in EAM
- Ruler dropped to nasal bridge
