Research

90Y Microsphere Therapy

We have developed quantitative 90Y SPECT/CT imaging techniques that provide voxel-level absorbed dose estimates to tumors and normal liver. We are characterizing tumor dose-response curves for primary and metastatic liver tumors following 90Y-microsphere therapy. The long-term goal is improving the response rates by using a prescriptive 90Y-microsphere therapy plan based on the tumor control probability curves.

More specifically, we are investigating the tumor dose response of hepatocellular carcinoma (HCC) and metastatic neuroendocrine tumors (mNET) for 90Y microsphere therapies. Studies are underway to assess the clinical implications of estimating tumor doses in vivo using different dosimetry models (MIRD, partition model, voxel-dosimetry) and different patient imaging modalities (99mTc-MAA SPECT/CT, 90Y SPECT/CT, 90Y PET/CT).

Collaborators: Armeen Mahvash, M.D.; Veera Baladandayuthapani, Ph.D.

Voxel-Based Absorbed Dose Calculations

We are evaluating deterministic (Grid-Based Boltzmann Solver) methods of radiation transport for fast and accurate patient-specific dosimetry calculations in targeted radionuclide therapies for nuclear medicine.  We have performed the fundamental work of implementing and validating GBBS for photons and beta emission used in nuclear medicine. We are currently adapting this approach for patient-specific imaging and dosimetry.

We have also investigated various voxel-dosimetry calculation techniques (Monte Carlo DOSXYZnrc, kernel-based, local deposition, etc.). We are investigating their dosimetric implications in 90Y microsphere therapy in the liver, lung, and in the liver/lung interface.

Collaborators: Firas Mourtada, Ph.D. (Christiana Care, Newark, DE), Todd Wareing Ph.D. (Varian, Seattle, WA)

Molecular Breast Imaging

Molecular Breast Imaging (MBI) is a new emerging breast-specific nuclear medicine imaging technique that uses a small field-of-view dual-headed semiconductor-based gamma camera in a mammographic configuration specifically designed to obtain high resolution images of 99mTc-sestamibi uptake in the breast.

We are developing novel image acquisition and post-acquisition data processing techniques on GE Discovery NM750b to generate quantitative 99mTc-sestamibi MBI images. We are also assessing the clinical role of MBI images as an early predictor of response for patients with breast cancer undergoing neoadjuvant chemotherapy.

Collaborators: Maia Rauch, M.D.; Aaron Jessop, M.D.

Quantitative Imaging

We have performed a comprehensive evaluation of material decomposition with rapid kVp-switching dual-energy CT scanners and investigated its use for assessing bone mineral density.

Both PET and SPECT Emission imaging suffer (relative to CT) from poor spatial resolution which impacts the quantitative accuracy of the image. We have developed novel image processing algorithms to establish voxel-based bounds on activity concentration – this new information will benefit clinical interpretation of PET/CT and SPECT/CT.

We are studying the effects of finite spatial resolution and system calibration on the quantitative accuracy of PET/CT and SPECT/CT using GATE Monte Carlo simulation.

We are investigating the effects of respiratory motion during clinical PET/CT and SPECT/CT data acquisition on the accuracy of patient-specific dosimetry calculations.