Video Rate optical verification tool for radiotherapy treatment plans - Abstract
For the first time, it is possible to directly visualize a radiation beam hitting a patient's tissue or high resolution
imaging of radiation delivery in water tank phantoms, using Cherenkov emission imaging. This allows the
opportunity to do pre-treatment verification at high resolution, with real time video of a test phantom, prior to
delivery to the patient. Radiotherapy has a diverse and increasingly complex number of delivery systems, yet
independent verification of these remains a time-intensive challenge for the medical physics support team.
Typically verification is only really utilized for the most complex stereotactic cases, where high resolution and
small beam sizes are critical. Yet these are exactly the situations where current tools to verify the plan have
limits. In order to not to overburden the system, verification tools must get better, faster and more accurate. The
competing technologies using ionization chambers or diode arrays which largely are low spatial resolution
devices or low temporal resolution, depending upon the configuration. A recent discovery that gated intensified
imaging allows video-rate detection of Cherenkov emission during radiation therapy has opened up a new
important paradigm in radiation oncology. This work has been invented and patented at Dartmouth, and
exclusively licensed to DoseOptics LLC, a spin-off of this research program with the goal to advance video-rate
Cerenkov imaging as a dose delivery imaging tool. The alpha prototype developed in this first phase 1 application
showed that a low cost system could be prototyped for IMRT/VMAT verification in water tank imaging, called C-
Verify. The C-Verify system will be further produced into a handful of Beta units which will be tested at partner
academic medical center, as well as within an MRI-guided radiotherapy unit. The system will achieve video-rate
capture of IMRT/VMAT data at sub-millimeter spatial resolution, and will be combined with external portal
imaging device data for full 3D volumetric video rate validation of treatments. The integration of specialized
anatomic and motion body phantoms will round out the test product lines for this badly needed advance in
radiotherapy. The software tool will allow the non-expert user to directly compare to the treatment plan, using
standard gamma analysis conventions expected for verification. The work carried out in the company is
augmented by a plan to evaluate the system in Clinical Physics at Dartmouth, and be further evaluated at
Stanford, UPenn and WashU. The technology patent protected as developed by this group, and for this start up,
the team of developers includes a substantial number of experts in Cerenkov imaging, medical physics and new
venture creation.
