Transcript Body-Section Radiography

Advantages of MRI
• Higher resolution of tissues
• No ionizing radiation
• Multiplanar imaging
Disadvantages of MRI
• Long imaging time
• Hazards with ferromagnetic metals
(pacemakers, vascular clips, etc)
• Claustrophobia
• Higher cost
Relative Brightness of Tissues
Fat
Marrow
Brain
Muscle
Body Fluid
TMJ Disk
Cortical Bone
Air
White
Gray
Black
Nuclear Medicine
Nuclear Medicine
• Radioactive compounds
• Target tissues
• Radioactive agents pools in the
target tissues
• Detected and imaged by external
detectors (gamma camera).
Nuclear Medicine
• Shows structure and function of the
target tissues
• Static and dynamic conditions
• Scintigraphy scans or RN
(radionuclide) scans
• Bone scans or salivary gland scans
Technetium
• 99mTcO4- - thyroid and salivary
gland scan
• 99Tc phosphate - bone scan
• Is this an active
disease?
Phases of Salivary Gland Scan
• Flow phase:
– Five to 10 mCi of 99mTcO4
– first 30 to 120 seconds
– shows flow of blood
• Concentration phase:
– next 30 to 45 minutes
– demonstrate the anatomy and function
• Washout Phase:
– administer sialagogue
– demonstrates secretory capabilities
Cephalometric Radiography
• Reproducible and standardized views
• For measurements and assess growth
• Fixed source to film distance – 60
inches
• Cephalostats and earplugs help in
reproducible positions
Cephalometric Radiography
Contrast Agents
Contrast Agents
• Radiopaque materials
• Water soluble
• Fat soluble
• 28 – 38% iodine
Phases of Sialography
• Ductal
• Acinar
• Evacuation
Indications of Sialography
• Acute swelling secondary to ductal
obstruction
• Recurrent Inflammation
• Palpable salivary gland mass
• Autoimmune Sialadenitis
Contraindications of
Sialography
• Sensitivity to contrast agents
• Acute Sialadenitis
• Limited use in tumor diagnosis
Scintigraphy
Sialography
Radioactive material Radiopaque material
Through blood
stream
All glands imaged at
the same time
Imaged by gamma
camera
Through duct
One gland at a time
Imaged by
fluoroscopy
Contrast Studies:
Arthrography
Arthrography
• Contrast media is introduced in joint
spaces
• Upper vs. lower joint space
• Viewed by Image Intensifier Fluoroscopy
• Video recording allows study of joint
movement
Contrast Material Injection
Open Position
• Translation of
condyle
• Reduction of disk