Sarah Patch

Associate Professor

Professional Website
Phone: (414) 229-4475

Office: 424

Research Interests: Medical Imaging; Tomography; Image Reconstruction.

Related Links:

Sarah Patch


Algorithm development for direct image reconstruction is Dr. Patch's area of training, although she currently collects experimental data. Her current research focus is thermoacoustic tomography (TCT), a hybrid imaging technique. Her long-term goal is to quantify the robustness of TCT across different sizes, depths, and types of cancer. Ideally, TCT deposits electromagnetic (EM) energy impulsively in time and uniformly throughout the imaging object, causing thermal expansion. Rapid thermal expansion generates thermoacoustic signals which are detected by ultrasound receivers placed outside of the object. Different types of tissue absorb different amounts of EM energy, which leads to variable heating and thermal expansion throughout the object. By "listening" for the emitted TA pulses from different locations around the object, she collects a TCT dataset (sinogram) similar to those collected by x-ray CT scanners. Dr. Patch has developed an inversion formula for idealized TCT data and now works to account for physical and experimental effects upon TCT data.

The Patch Lab utilizes very high frequency (VHF) EM energy to enable whole organ imaging. Choices for frequencies often impact the contrast mechanism and imaging depth. For instance, optical energy is preferentially absorbed by hemoglobin in blood and has a penetration depth of less than 2 cm in soft tissue. Microwaves heat pure (deionized) water and can develop standing waves in tissue creating "hotspots" and also "coldspots" from which no thermoacoustic information is available. (Recall uneven heating in microwave ovens without rotary tables.) Very high frequency energy is absorbed by ions which are present in electrically conductive blood and other fluids. Also, VHF energy is used to excite Magnetic Resonance Imaging (MRI) signals and can easily penetrate the abdomen of a large adult, enabling whole organ imaging.

Biographical Sketch:

Sarah Patch received her B.S. in Mathematics & Computational Sciences from Stanford University in 1989 and her Ph.D in Applied Math from UC Berkeley in 1994. She then obtained a National Science Foundation Postdoctoral Fellowship in Mathematical Sciences and worked at the Institute for Mathematics and its Applications from 1994 to 1995. In 1995, she was awarded a Humboldt Postdoctoral Fellowship to work at the University of Muenster, Germany. The following year Patch went back to Stanford University. From 1997 to 1999 Patch held a position GE’s Corporate Research and Development Center; in 2005 she joined GE Medical Systems’ Applied Science Lab in Milwaukee.

Since 2005, Sarah Patch has been working at University of Wisconsin-Milwaukee, where she holds the rank of Associate Professor. Professor Patch has received more than 10 patents and her current research is supported by a UW-Milwaukee Research Growth Initiative Award.

Selected publications:


Book Chapters