RAD L2 - How to take radiographs

Question 1

what is a radiograph

Answer 1

record of image produced by transmission of x-rays through an object

Question 2

what is radiology

Answer 2

interpretation of radiographic image

Question 3

what do you need to produce a radiographic image

Answer 3

patient
x ray machine
image receptors
film holder
operator
processing facility
reading facility

Question 4

what are the main 2 types of radiograph

Answer 4

single plane

multi-planar

Question 5

what are the 2 types of single plane radiographs

Answer 5

intra + extra oral

Question 6

what are 3 types of intra oral single plane radiographs

Answer 6

peri-apical
bitewing
occlusal

Question 7

what are 3 types of extra oral single plane radiographs

Answer 7

panoramic tomogram
lateral Ceph.
lateral oblique

Question 8

what is 1 example of multiplanar radiograph

Answer 8

CBCT - cone beam computed tomography

Question 9

how would you ideally take a radiograph

Answer 9

1. tooth + sensor close as possible
2. long axis of tooth + sensor/film should be parallel
3. x ray beam positioned so meets tooth + sensor at 90°
4. position should be reproducible

Question 10

what problems can occur when taking a radiograph

Answer 10

• teeth lie within bone - impossible to accurately determine root direction
• multi-rooted teeth
• anatomical structure (palate) prevent direct contact without bending receptor

Question 11

when is periapical radiographs done and how should they be taken

Answer 11

shows entire tooth + surrounding structures

should demonstrate 2-3mm bone all around apex of tooth

Question 12

what are 2 methods of take periapical radiograph

Answer 12

parallelling technique

bisecting angle technique

Question 13

why is paralleling technique preferred over bisecting angle tech when taking periapical radiographs

Answer 13

accurate + reproducible
reduction of radiation dose
use positioning aids

Question 14

describe the paralleling technique for periapical radiographs

Answer 14

• 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

Question 15

describe the bisecting angle technique for periapical radiographs

Answer 15

• 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

Question 16

what indications would you see that would tell you to take a periapcial radiograph

Answer 16

• 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

Question 17

what is occlusal radiography

Answer 17

radiographs where image receptor is placed in occlusal plane

Question 18

what are 2 types of occlusal radiography

Answer 18

maxillary

mandibular

Question 19

what are 2 types of maxillary occlusal radiography

Answer 19

upper standard occlusal

upper oblique occlusal

Question 20

what indications would you see that would tell you to take a occlusal radiograph

Answer 20

• periapical assessment of teeth
• detect presence of pathology
• parallax for unerupted teeth
• fractures of teeth/alveolar bone
• assess of roots displaced

Question 21

why is it important to give a patient a thyroid collar when doing upper standard/oblique occlusal radiograph

Answer 21

to protect thyroid - sensitive

Question 22

what are the 3 types of mandibular occlusal radiographs

Answer 22

lower 90° occlusal (true occlusal)
lower 45° occlusal
lower oblique occlusal

Question 23

what indications are there to know when to use a mandibular occlusal radiograph

Answer 23

• 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

Question 24

would you use a thyroid collar for lower occlusal radiograph

Answer 24

no

it obstruct + affect the image

Question 25

what is 1 type of extraoral radiography

Answer 25

panoramic

Question 26

what are some disadvantages of using extra oral panoramic radiography

Answer 26

- Image Quality - Operator dependant/ patient dependent - Ghost images and superimposition - ↑ Dose needed - Magnification

Question 27

what are some indication that would prompt you to take a extra oral panoramic radiograph

Answer 27

- 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

Question 28

explain the extra oral panoramic tomography ( how radiograph is taken)

Answer 28

- 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

Question 29

what is the focal trough - used in extra oral panoramic radiographs, + typically what shape is it and why

Answer 29

- 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.

Question 30

how to position patient head within focal trough in extra oral panoramic radiograph

Answer 30

- 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”

Question 31

what is a cephalometric x ray and when is it used

Answer 31

diagnostic radiograph used primarily for orthodontic treatment planning. - image shows the relationship between teeth, jaw + profile, helpful for orthodontic planning + realignment treatment

Question 32

what are some indication that would prompt you to take a cephalometric radiograph

Answer 32

(Orthodontic/Orthognathic) - Skeletal/soft tissue abnormalities - Treatment planning - Monitoring progress - Assess results of treatment

Question 33

what is the technique to use when taking a cephalometric radiograph

Answer 33

- 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