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?

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?

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)
   computes SUVmax
   computes SUVmean
   updates display
   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 (create custom PETCT LUT )
      • get good volume render for slides.
      • help from Nicole on min/max & LUT scaling -- access via volumes module (not exposed in API)?
    • test and verify SUV calculation
    • add unit correction for all vendors
    • detect vendor and use special calculations for Philips
    • improve overall usability
      • propagateVolumeSelection after touching node selectors auto-fits data to win -- so annoying! fix.

PPT files

Slides for Volumetric Analysis (in progress)