Slicer3:UIDesign:WorkingProblems:BCAnalysis:PET

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SUV Analysis for Breast Cancer

Goal

Goal is to accommodate basic RECIST assessment for breast cancer (Response Evaluation Criteria In Solid Tumors). (RECIST is a set of published rules that define when cancer patients improve ("respond"), stay the same ("stable") or worsen ("progression") during treatments).

• Determine features that currently exist in Slicer
• Develop features that don't
• Provide a framework that knits features together in a comfortable workflow.

PET SUV Analysis Workflow

• Segment the tumor by hand (ROI or VOI, can be simple circle or ellipsoid)
• Compute SUV of baseline
  • extract parameters from dicom header including
    • concentration
    • injected activity
    • patient weight
  • SUV = ( concentration (microcuries/cc) / injected activity (microcuries) ) - (patient weight (g))
  • use maximum value
• Compute SUV of followup
  • extract parameters from dicom header including
    • concentration
    • injected activity
    • patient weight
  • SUV = ( concentration (microcuries/cc) / injected activity (microcuries) ) - (patient weight (g))
  • use maximum value
• Normalize ROI by SUVmax
• Resport parameters of interest
  • SUVmax_baseline,
  • SUVmax_followup,
  •  % change
• For multiple tumors, report
  • sum of SUV_baselines
  • sum of SUV_followup
  • percent change

Approach

Started a PET_SUV module in Slicer that

• lets you choose a pre-treatment pet volume
• lets you choose a post-treatment CT volume (if present)
• lets you choose pre & post-treatment label maps.
• displays them in FG/BG with correct LUT
• pulls parameters of interest for SUV calculation from DICOM header
• has entry widget for parameters missing from header
• computes measures of interest as described above.
• no special viewer for now.
• ...

Resources

Display guide

case study MS PPT Slides shows tumor

MS Word document with DICOM tags for SUV

Slicer Display at present

Initial view in Slicer (w/o volume rendering)

Ron's PETCT in Slicer: GPU Raycasting (GLSL) with Gradient Magnitude Opacity Modulation

Draft module (w/o display) DICOM Tags missing?

TODO & Questions for Ron/Jeffrey

• Same case as Draft display -- same case as ppt slides?
• Check DICOM tags; not all are found for computing suv?
  • Radiopharmaceutical Start Time (0018,1072)
  • Decay Correction (0054,1102)
  • Decay Factor (0054,1321)
  • Frame Reference Time (0054,1300)
  • Radionuclide Half Life (0018,1075)
  • Series Time (0008,0032)
  • Patient Weight (0010,1030)
  • Radionuclide Total Dose (0018,1074)
  • Correction (7053,1009) (counts to Bq/cc)
  • Philips SUV Factor (7053,1000) (custom)
• Normalize ROI by SUVmax?
• Get good volume render for slides.
• Help from Nicole on min/max & LUT scaling -- access via volumes module (not exposed in API)?
• PropagateVolumeSelection after touching node selectors auto-fits data to win -- so annoying! fix.

Approach & STATUS

For each label value/color:
 create a binary volume that includes only that label
 use that binary as a stencil on the PET volume
 if the number of voxels in the stenciled image > 0
   get the maximum Cpet
   get the mean Cpet
   (no max_mean yet)
   no unit conversion yet (assumes MBq/ml

• will work for single or multiple tumors under one label
• can be made to work for different labels, if want to assess tumors separately.
• need to:
  • wire up display panel inside module
  • test and verify SUV calculation
  • add unit correction for all vendors
  • detect vendor and use special calculations for Philips
  • improve overall usability

PPT files

Slides for Volumetric Analysis (in progress)