Snyder Building, Room 156
Snyder Building, Rooms 136 & 137
​P.O. Box 801339
Charlottesville, VA 22903
Medical Imaging Research Detector Lab


Mark B. Williams received his PhD in physics at UVa in 1990. Following several years with the UVa Physics Department as a Research Scientist he joined the Radiology faculty. His lab applies physics principles to the design and development of systems for medical imaging.


B.S. ​Physics, Grinnell College, 1977

M.S. ​Physics, Wake Forest University, 1983

Ph.D. ​Physics, University of Virginia, 1990

Post-Doc ​Physics, University of Virginia, 1990-1992

We develop novel medical imaging systems to be used for early detection and characterization of disease, and for guiding and assessing therapy.


Research Interests

Medical and Molecular Imaging
Biomedical Data Sciences
Quantitative Biosciences

Selected Publications

Comparison of Breast Specific Gamma Imaging and Molecular Breast Tomosynthesis in Breast Cancer Detection: Evaluation in Phantoms. Medical Physics 2015; 42(7):4250-4259. PMCID: PMC4474957 GONG Z AND WILLIAMS MB.
Intraoperative imaging guidance for sentinel node biopsy in melanoma using a mobile gamma camera. Annals of Surgery 2011; 253(4):774-778. PMID: 21475019 DENGEL LT, MORE MJ, JUDY PG, PETRONI GR, SMOLKIN ME, REHM PK, MAJEWSKI S, WILLIAMS MB, AND SLINGLUFF CL.
Dual modality breast tomosynthesis. Radiology 2010; 255(1):191-198. PMID: 20298564. PMCID: PMC2843832 WILLIAMS MB, JUDY PG, GUNN S, MAJEWSKI S.
Tomographic Mammography Using a Limited Number of Low-Dose Cone-Beam Projection Images. Medical Physics 2003; 30(3):365-380. Winner of the Sylvia Sorkin Greenfield Award for the best paper published in Medical Physics in 2003. PMID: 12674237 WU T, STEWART A, STANTON M, MCCAULEY T, PHILLIPS W, KOPANS DB, MOORE RH, EBERHARD JW, OPSAHL-ONG B, NIKLASON L, AND WILLIAMS MB.
Combined Structural and Functional Imaging of the Breast. Technology in Cancer Research and Treatment 2002; 1:39-42. PMID: 12614175 WILLIAMS MB, MORE MJ, NARAYANAN D, MAJEWSKI S, WEISENBERGER AG, WOJCIK R, STANTON M, PHILLIPS W, AND STEWART A.
Noise Power Spectra of Images from Digital Mammography Detectors. Medical Physics 1999; 26(7):1279-1293. WILLIAMS MB, MANGIAFICO PA, AND SIMONI PU.
Analysis of the Detective Quantum Efficiency of a Developmental Detector for Digital Mammography. Medical Physics 1999; 26(11):2273-2285. WILLIAMS MB, SIMONI PU, SMILOWITZ L, STANTON M, PHILLIPS WC, AND STEWART A.

Featured Grants & Projects

Dual modality tomosynthesis breast imaging We have developed an integrated imaging system that combines the sensitivity of digital breast tomosynthesis with the specificity of molecular breast imaging (breast-specific gamma imaging) in a single upright unit. The system is designed to obtain diagnostic information regarding suspicious or radiographically occult mammographic findings, and functions by obtaining sequential series of x-ray transmission and gamma emission images over a limited range of viewing angles with the breast in a single configuration. Co-registration then correlates the 3-dimensional x-ray and gamma ray tomosynthesis images to within a fraction of a voxel. This system is currently being evaluated in a human study among women schedules for breast biopsy.
Tomographic molecular breast imaging We are adapting a two-head gamma camera designed for conjugate imaging of the breast to permit dedicated breast SPECT. The acquisition geometry is upright and seated. Iterative SPECT image reconstruction incorporates resolution recovery and results in nearly isotropic spatial resolution. The utilization of two independently positioned cameras permits sampling artifact-free performance with clinically acceptable acquisition time. Breast immobilization (rather than compression) is accomplished using a unique structure that permits small collimator-to-skin separation throughout the scan while maintaining a natural, comfortable breast shape.
Dedicated breast ring PET Clinical whole body PET (WBPET) scanners have inadequate spatial resolution to reliably detect primary breast malignancies smaller than 1 cm. Our group is developing and evaluating a breast ring PET (BRPET) scanner that uses a full ring of 12 detectors that surround the breast for high spatial resolution and high photon detection sensitivity. Each detector in the ring contains a 5 cm x 5 cm array of high density lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystals whose light emission is channeled to a position sensitive photomultiplier tube via a slanted fiber optic light guide. The slant design permits the scintillator crystals to be placed up inside the table hole, mitigating the deficiency of virtually all other prone table breast imaging systems: limited visualization of structures or tracer near the chest wall. The BRPET scanner is being evaluated in a pilot study comparing its sensitivity, specificity, positive and negative predictive values against those of contrast-enhanced breast MRI.
Intraoperative SPECT imaging using a handheld gamma camera In collaboration with Dilon Technologies, SurgicEye, and the Jefferson Lab, we are developing and evaluating a system for radio-guided surgical procedures such as sentinel lymph node biopsy. The system uses infrared tracking of a handheld gamma camera to create a 3-D map of the distribution of gamma-emitting compounds (e.g. lymphatic or tumor-targeting radiotracers) during surgery. The camera is based on silicon photomultiplier (SiPM) technology, resulting in a compact device that is light enough to be hand-operated. The system is being evaluated among melanoma patients undergoing sentinel lymph node biopsy. It is anticipated that, compared to current practice utilizing pre-operative lymphoscintigraphy using large area, general purpose gamma cameras followed by intraoperative node excision using non-imaging gamma probes, the handheld SPECT system will result in more accurate node localization, less ambiguity for the surgeon, and greater comfort for the patient.