Photo Acoustic Tomography

 
 

Overview

My research is primarily focused on photoacoustic imaging, a cutting-edge technology that has drawn considerable attention in the medical imaging area.  Currently we have already established several very promising projects that apply this technology in different medical fields.


1. Imaging and treatment of inflammatory arthritis


The first adaption is the imaging and treatment of inflammatory arthritis which will be awarded with a NIH Bioengineering Research Grant. This 4-year (2008-2012) project is carried on by a multi-disciplinary team comprised of experienced researchers at the Department of Radiology and Division of Rheumatology at University of Michigan School of Medicine, and the Department of Chemical Engineering at the University of Michigan Engineering School. By imaging gold nanorod conjugated anti-rheumatic drug in arthritic rat joints in vivo, photoacoustic imaging provides not only a unique opportunity for direct visualization of drug upake by inflammatory articular tissues but also very comprehensive evaluation of treatment effecacy. Through the studies on arthritic disease animal model, we will explore the feasibility to develop the novel noninvasive nonionizing photoacoustic imaging technology for molecular imaging and drug delivery monitoring with both excellent sensitivity and high spatial resolution. If the designed experiments prove successful, this technology may contribute considerably to comprehensive evaluation of pharmaceutical treatment in living laboratory animals. Moreover, in another study which is supported by Arthritis National Research Foundation, the feasibility of photoacoustic imaging of human rheumatoid arthritis will be explored. Since photoacoustic imaging of human peripheral joints has been validated, the transition from lab prototypical device to compact instrument used in a clinical setting is extremely promising.



                       Normal Joint                                                  Inflamed Joint


         


Figure 1. PAT of Normal and Inflammatory Joints




                                                         Human PIP Joint



Figure 2. PAT of Human Finger Joint vs. Histology - I.  (AP: aponeurosis; PH: phalanx; SK: skin; SU: subcutaneous tissue; TE: tendon; VP : volar plate).




                                                         Human DIP Joint




Figure 3. PAT of Human Finger Joint vs. Histology - II.  (AP: aponeurosis; PH: phalanx; SK: skin; SU: subcutaneous tissue; TE: tendon; VP : volar plate).




2. Novel imaging and diagnostics of prostate cancer


Another application of photoacoustic technology is to conjugate spectroscopic photoacoustic imaging to conventional transrectal ultrasound for prostate cancer detection and evaluation, as well as for future treatment planning and therapeutic monitoring. The design and fabrication of a photoacoustic prostate imaging system is now supported by the Department of Defense Prostate Cancer Program. After the photoacoustic-ultrasound dual-modality prostate imaging system is built, its performance in imaging prostate tissues and in quantifying functional hemodynamic changes will be examined through the studies on canine prostates in vivo. In another study on ex vivo human prostate tissues, we will validate a new photoacoustic based diagnostic method, i.e. photoacoustic spectral analysis, which may prove powerful in prostate tissue characterization. This pilot study is now supported by U-M Prostate SPORE Program. We expect that based on the excellent optical contrast, this system will present good sensitivity and specificity in differentiating malignent prostate tissue specimens from normals.



Canine Prostate PAT

                     700 nm                                     750 nm                            Photograph

     



Figure 4. PAT of ex vivo Canine Prostate.




Acknowledgement:  Funded in part by the Arthritis National Research Foundation (ANRF) and the Department of Defense Prostate Cancer Research Program.


 

Photo Acoustic Imaging of Vascular Spaces
for Diagnosis and Treatment


Xueding Wang, Department of Radiology, University of Michigan, Ann Arbor, MI 48109-0553 USA

Artery

Skin

Muscle

Fat

Fat

Muscle

Muscle

Vein

Vein

Bone

Vein

Fat

Fat

Synovium

Muscle

Artery

Skin

Vein

Bone

Muscle

Muscle

Fat

Fat

Muscle

Muscle

Vein

Vein

Fat

Fat

Photoacoustic image

Histological picture

Synovium

1 mm

Imaging of Rat Tail Joint