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Quantitative simultaneous 111In∕99mTc SPECT-CT of osteomyelitis
Morgan Cervo1, Victor H Gerbaudo, Mi-Ae Park
1Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA. mcervo@bwh.harvard.edu
Monte Carlo-based joint OSEM (MC-JOSEM) improved quantitative accuracy for 99mTc sulfur colloid (SC) in dual-radionuclide SPECT-CT imaging for osteomyelitis (OM). While MC-JOSEM showed marginal benefits over triple-energy window-based reconstruction (TEW-OSEM), further clinical studies are needed.
Area of Science:
- Nuclear Medicine
- Medical Imaging
- Quantitative SPECT-CT
Background:
- Osteomyelitis (OM) diagnosis relies on visual assessment of dual-radionuclide SPECT-CT using 99mTc sulfur colloid (SC) and 111In white blood cells (WBC).
- Accurate quantitative imaging requires addressing noise, scatter, and crosstalk during reconstruction.
- Current methods lack sufficient quantitative precision for reliable diagnosis.
Purpose of the Study:
- To compare a Monte Carlo-based joint OSEM (MC-JOSEM) algorithm with conventional triple-energy window-based OSEM (TEW-OSEM) and uncorrected OSEM (NC-OSEM) for quantitative SPECT-CT in OM.
- To evaluate the impact of scatter and crosstalk compensation on image quality, bias, and precision.
- To assess the clinical utility of quantitative 111In/99mTc SPECT-CT.
Main Methods:
- Numerical and acquired phantom studies simulating bone infection sites with varying 111In/99mTc ratios.
- Reconstruction of SPECT-CT data using MC-JOSEM, TEW-OSEM, and NC-OSEM algorithms.
- Evaluation of bias and precision using mean counts in volumes of interest (VOIs) for simulated and acquired phantom data.
- Qualitative assessment of patient image reconstructions for lesion contrast and spatial definition.
Main Results:
- Both MC-JOSEM and TEW-OSEM significantly improved the root-mean squared-error of 99mTc activity compared to NC-OSEM.
- MC-JOSEM demonstrated a significant improvement over TEW-OSEM for the acquired bone phantom (p<0.001).
- Scatter correction did not significantly improve 111In quantitation in any tested scenario.
Conclusions:
- Scatter and crosstalk compensation enhance the quality, bias, and precision of 99mTc activity estimates in dual-radionuclide SPECT-CT for OM.
- MC-JOSEM offers marginal quantitative improvements over TEW-OSEM.
- Further clinical studies with more subjects are necessary to validate the usefulness of quantitative 111In/99mTc SPECT-CT.
