SPECT/CT and registration

Question 1

Benefits of CT

Answer 1

• Hybrid systems combine functional &
  anatomical imaging in a single study
• CT significantly improves
• Attenuation correction
• Anatomic localization

Question 2

Attenuation correction CT

Answer 2

• Pixel values require transformation
• Hounsfield units (HU) to attenuation coefficients
• CT number = [(μt – μw) x k] /μw
• μt = LAC of tissue
• μw = LAC of water
• k = 1000 (constant)
• Adjusted for energy differences between photons being imaged and CT

Question 3

Image Co-Registration Steps

Answer 3

• Decide on the role for the data sets
• Decide on the type of information used to register
• Define the allowed transformation
  between the model and the reference
• Define the goodness of match criteria
• Perform optimization

Question 4

Forms of registration

Answer 4

• Interactive
• Landmark Based
• Surface Matching
• Automatic
• Maximization of Mutual Information
• Elastic

Question 5

Instrumentation and QA

Answer 5

• Gamma Camera
• CT Scanner
• Operation of each scanner as an individual piece of equipment is possible
• QC and preventative maintenance (PM) as it applies to each scanner is required

Question 6

Clinical Applications

Answer 6

• Myocardial Perfusion Imaging
• 99mTc MDP
• 111In WBC
• 99mTc HMPAO WBC
• 131I WBS
• 123I MIBG
• 111In Octreotide
• 67Ga