Innovation and Partnerships Office

High Energy Gamma-Ray Imaging and Proton Therapy Dose Verification 2013-076


  • Cancer treatment – proton therapy dose verification
  • Monitoring for homeland security and nuclear nonproliferation
  • Other applications that require imaging of high energy gamma ray sources


  • Real time monitoring
  • A combination of high imaging sensitivity and resolution
  • More complete and accurate presentation of the proton beam inside a target: up to 8.75 times higher sensitivity and 3 times higher resolution than single knife-edge slit collimator designs


Lucian Mihailescu of Berkeley Lab has invented a technology optimized to image high-energy gamma rays with high position resolution and sensitivity. The technology can monitor, in real time, the proton or heavy ion beam during radiation therapy to treat localized malignant tumors, thus enabling users to guide and adjust treatments so a minimal radiation dose is delivered to healthy tissue. It also provides a fail-safe mechanism for avoiding accidental overtreatment. The system can be used for other applications involving imaging of sources of high-energy gamma rays such as characterizing and diagnosing materials by active interrogation using gamma rays, hard X-rays, neutrons, or other beams.

The Berkeley Lab imaging technology consists of an assembly made out of a multi-slit knife-edge collimator and a high efficiency position sensitive detector. Unlike other knife-edge collimators where a single slit collimator perpendicular on the proton beam direction projects a 1-D image of the beam, the new system uses multiple, intersecting knife-edge slits orientated at multiple angles in respect to the direction of the proton beam, and an image reconstruction algorithm provides a 2-D image of the distribution of the gamma-ray emissions. This approach increases the sensitivity by a factor of 8.75 and the resolution by a factor of 3 when compared to the single knife-edge slit collimator designs. Thus, the system can provide a much more complete and accurate representation of the proton beam.

Over the past years, fatal accidents of radiation treatments occurred because of much higher deliveries of doses than planned as well as misplacement of the radiation doses. The previous attempt to monitor dose delivery used PET imaging, which has limited use for real-time monitoring due to long decay times of the beta+ emitters and low counting statistics.

STATUS: Patent pending. Available for licensing or collaborative research.

DEVELOPMENT STAGE: A prototype has been built. Preliminary measurements are being performed.


Human Blood Molecular Biodosimeter Panel for Distinguishing Radiation Exposure from Inflammation Stress, IB-3304

Assay to Determine Sensitivity to Radiation, IB-3203