Ultrasound and acoustic resolution photoacoustic microscopy: A novel modality for surveilling human rectal cancer after therapy

Xiandong Leng, William Chapman, Sreyankar Nandy, Ruimin Chen, Qifa Zhou, Deyali Chatterjee, Matthew Mutch, Quing Zhu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Surgery for rectal cancer is associated with significant side effects including wound infections, incontinence, sexual and bladder dysfunction, and long-term ostomies. Though studies have shown that patients who completely respond to preoperative treatment can safely avoid surgery, nonoperative options remain limited by the poor performance of MRI and endorectal ultrasound after initial therapy. Therefore, new imaging modalities are needed to improve posttreatment tumor assessment and enable the widespread adoption of nonoperative management in rectal cancer. An acoustic resolution photoacoustic microscope (AR-PAM) was constructed with high frequency ultrasonic transducer and near infrared laser. We performed initial phantom, and then imaged ex vivo human colorectal specimens to evaluate different AR-PAM characteristics in each tissue type (normal, untreated tumor, and treated tumor). Our data suggest that photoacoustic imaging can differentiate the distorted vasculature of rectal tumors from normal vascular patterns. However, the vascular distribution of rectal tissue in pathological complete responders showed similar distribution as the normal colorectal tissue; mucosa, submucosa and muscle layer are clearly presented in ultrasound images, while photoacoustic images have revealed that most vasculatures distribute in submucosa. Encouraged by these initial results, we are developed a high-speed scanning (1 second for 20mm B-scan) AR-PAM with laser pulse repetition rate of 1kHz for large field 3D imaging. Lateral resolution of 65μm, axial resolution of 45μm, and 8mm tissue imaging depth can be achieved.

Original languageEnglish
Title of host publicationPhotons Plus Ultrasound
Subtitle of host publicationImaging and Sensing 2019
EditorsLihong V. Wang, Alexander A. Oraevsky
ISBN (Electronic)9781510623989
StatePublished - 2019
EventPhotons Plus Ultrasound: Imaging and Sensing 2019 - San Francisco, United States
Duration: Feb 3 2019Feb 6 2019

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferencePhotons Plus Ultrasound: Imaging and Sensing 2019
Country/TerritoryUnited States
CitySan Francisco


  • Acoustic resolution photoacoustic microscopy
  • Laser
  • Photoacoustic imaging
  • Rectal cancer
  • Therapy
  • Ultrasound


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