oncology and bony imaging Flashcards
What are the methods of bony imaging?
CBCT or CT
MRI to check for marrow changes
What is the beam shape of CBCT and CT?
CBCT - cone beam
CT - fan shaped
Compare the dose of CBCT and CT
CBCT - low dose
CT - high dose
Describe the soft tissue contrast of CBCT and CT
CBCT - poor soft tissue contrast
CT - good, uses windowing
Describe the patient position of CBCT and CT
CBCT - upright/standing
CT - lying horizontal
What is used for TMJ imaging?
Myofascial - no imaging required
Internal derangement - MRI is gold standard, ultrasound as alt
Degenerative - CBCT
How is internal derangement of TMJ imaged?
Disc is visualised on MRI
Can determine if with or without reduction and which direction the disc moves in relation to they condyle
Need to view in para-sagittal (along short axis of condyle) and para-coronal (along long axis of condyle)
What is SPECT?
Single photon emission computed tomography
Uses the radionuclide 88mTc to check for activity of the TMJ
Only used as a screening method
Useful to see condylar hyperplasia
What imaging methods can be used for head and neck oncology?
CT
MRI
PET
OPT for dental assessment prior to radiotherapy
Ultrasound
What are the advantages of MRI over CT?
MRI has no radiation dose to the pt
MRI better for assessing perineural spread, bone invasion via bone marrow changes and soft tissue characteristics of lesion
What are the advantages of CT over MRI?
MRI takes longer
More contraindications for MRI - pacemaker, cochlear implants, claustrophobia
What is PET?
Positron emission tomography
Radioactive fluorine labelled glucose injected
Doesn’t give anatomical detail so overlaid onto CT or MRI
When is PET useful?
Good for looking for unknown primary tumours
Useful for follow-up and recurrence
