Feb 3- Special Imaging Techniques Part 2

Question 1

Compare the amount of radiation in a CBCT to a full mouth series, ceph, pan and CT

(Dont need to memorize numbers)

Answer 1

the important thing to understand is that in terms of radiation dose: CT>CBCT>PAN>CEPH>intra oral radiographs

Question 2

Name a use of CBCT(1)

Answer 2

TMJ Assessment

Question 3

Name of use of CBCT (2)

Answer 3

Implant Placemment

Question 4

Name a use of CBCT (3)

Answer 4

Pathology

Question 5

How big is the magnification error in CBCT’s?

Answer 5

None, the ratio is 1:1

Question 6

The science we need to know about magnetic resonance imagining (MRI)

Answer 6

We are looking at the speed and the amount of the radio frequency that is being released from hydrogen atoms.

Question 7

What type of imaging is this?

Answer 7

MRI

Question 8

What are the advantages and disadvantages of MRI?

Answer 8

Benefits: No ionizing radiation (uses magnets and radiowaves)

Disadvantages: long wait time to get them, not available to dentists, must be done in a hospital.

Side note: application in dentistry is looking at intra-articular disc

Question 9

What is the difference between nuclear medicine and CBCT/CT?

Answer 9

1. In nuclear medicine, the radiation comes from within the patient not outside.
2. Nuclear medicine also shows function and therefore is know as functioning imaging.

Question 10

What type of imaging is Positron Emission Tomography (PET)?

How is it unique?

What is it good for?

Answer 10

1. Nuclear Medicine
2. Radioactive particles give of multiple beams of radiation so you can get 3D funtioning scan. When overlapped with a CT it is very useful.
3. Cancer growth and Cancer Metastasis

Question 11

Name two ways CbCT dose can be reduced to comply with the ALARA principle.

Answer 11

1. Prescription Radiography- ie: dont scan every single patient, only scan the people you need to scan. If you can get away with bitewings use bitewings
2. Change parameters-

Adjust the field of view so that you only get what you need
Adjusting the scanning time can reduce radiation exposure but will also reduce resolution

Question 12

what are the advantages and disadvantages of CbCT?

Answer 12

Advantages:

• 1:1 images, no magnification
• sectional images
• no superimposition of surrounding tissues

Disadvantage:
-poor clarity due to relatively low radiation exposure (compared with medical CT)

• only useful in looking at boney structures