====== Photoacoustic Ultrasound Registration and Visualization ======

Photoacoustic (PA) registration has been shown to be able to at least replicate the functionality of common surgical tracking systems such as electromagnetic or optical trackers. This technology involves shining laser points onto a phantom or tissue that can be seen by a stereovision camera system. The laser energy is absorbed by the phantom or tissue and generates an acoustic wave due to the photoacoustic effect that can be detected by an ultrasound probe.

The goal of this project is to develop a PA registration and visualization system that can perform a direct registration from 3D stereocamera (SC) space to 3D ultrasound space in an ex-vivo tissue environment and achieve sub-millimeter error results based on target registration error (TRE). 

**Note:** A predecessor 600.446 course project was [[courses:446:2011:446-2011-9:vyaskimxu|Interventional Photoacoustic Registration]]
and
[[https://ciis.lcsr.jhu.edu/dokuwiki/doku.php?id=courses:446:2012:446-2012-09:project09|Photoacoustic Registration and Visualization]]

===== Project Goals =====

  - Integrate new laser system (DONE)
  - Engineer fibre optic laser delivery system (DONE)
  - Stereovision camera to 3D Ultrasound Registration (DONE)
  - Demonstrate registration
    - image overlay (DONE)
    - video overlay
  - Verify laser compatibility with stereocamera (DONE)
  - ex-vivo organ testing (DONE)
  - Registration of pre-operative CT model using photoacoustic imaging fiducials
  - Multi-spot fiber delivery (DONE)
  - Multi-spot fiber delivery experiments with ex-vivo organ (In Progress)
  - In-vivo testing (In Progress)
  - Photoacoustic subsurface fiducial registration (In Progress)
  - Test penetration depth of different laser wavelengths (In Progress)

===== Deliverables =====

  * **Minimum Deliverables**
    * Functioning setup with new laser source and optic fiber delivery system (Done)
    * Stereovision camera to 3D Ultrasound Registration (Done)
    * Demonstrate registration
      * image overlay (Done)
      * video overlay
    * Verify laser compatibility with stereocamera (Done)

  * **Expected Deliverables**
    * Get system working with daVinci

  * **Maximum Deliverables**
    * ex-vivo organ testing (Done)
    * Registration of pre-operative CT model using photoacoustic imaging fiducials
    * Subsurface photoacoustic imaging using contrast agents

===== Approach =====

  * Details can be found in the publications below
===== Status and Results =====

  * Demonstrated sub-millimeter TRE on synthetic phantoms and ex-vivo tissue
  * Demonstrated registration with multi-spot fiber delivery system on ex-vivo tissue
  * More details can be found in the publications below


===== Project Personnel =====
  * Emad Boctor, Assistant Professor, Radiology
  * [[http://cs.jhu.edu/~rht|Russell Taylor]], Professor, CS/ME/Radiology/Surgery
  * Alexis Cheng, Ph.D. student, CS

===== Funding =====
  * JHU Internal Funds
  * iPASS R21
  * NIH Ultrasound Calibration Grant
  
===== Affiliated labs =====
  * [[:start|Computer Integrated Interventional Systems Laboratory]]
  * [[https://musiic.lcsr.jhu.edu/|Medical UltraSound Imaging and Intervention Collaboration (MUSiiC) Lab]]
===== Publications =====
  * {{:research:photoacoustic_reg_vis:alexischeng-pa-miccai2012-publish.pdf|Direct 3D Ultrasound to Video Registration Using Photoacoustic Effect MICCAI 2012}}
  * {{:research:photoacoustic_reg_vis:pa-jbo2013-publish.pdf|Direct three-dimensional ultrasound to video registration using photoacoustic markers JBO 2014}}