Optical imaging of Cherenkov emission from tissue has recently been demonstrated, providing a mapping related to the radiation delivery to tissue. In external beam radiotherapy, the signal is optimally captured by time-gated intensified cameras, synchronized to the linear accelerator pulses, allowing rejection of the majority of background room light, and providing real time video of each radiotherapy treatment with standard dose rates. This discovery is the first time in history that radiation dose to tissue could be directly imaged with high spatial and temporal resolution. While the imaging technology has inherent limitations to surface regions, it also has the potential for a paradigm change in how radiotherapy is documented and archived for quality audit and real time control. The implementation of Cherenkov imaging is significantly simpler than most dosimetry tools, but needs to be quantitatively accurate to be competitive in the setting of documenting delivered dose. This technology development proposal advances the methods for correction for tissue curvature and tissue optical properties, two of the most dominant factors which alter the linearity between dose and Cherenkov emission. These important corrections are studied in partnership with leading companies that are advancing the methods for patient surface scanning, tissue optical property imaging and Cherenkov imaging system development, ensuring that the discoveries found here will translate into commercial implementation. The studies are tested in the pilot studies of breast cancer patient radiotherapy, in which patients receive up to five daily fractions per week, over 4 to 8 weeks. While radiotherapy delivery incidents occur in less than 1% of treatments, alignment of the patient for daily treatment is a disproportionally high source of errors. As a result, we will explore the applications of Cherenkov imaging in verification of the combined on-patient delivery of the beam, using visible vascular patterns of the breast that appear in the images of the treatment beam. We will also explore the similarity of Cherenkov intensity to thermoluminescent diode measurement, as a solution for verification that is potentially more accurate and easily implemented. Taken together, this project will advance on of the most compelling systems for radiotherapy imaging in decades. The core of the project is combined technology systems, testing the utility in the setting of whole breast irradiation. This technology is embryonic at this point, but its further development could shift the paradigm in what is capable for independent verification of radiation therapy delivery.

Public Health Relevance

Cherenkov imaging of radiation therapy delivery allows a real time visual mapping of the surface radiation deposited by the beam on the patient. Developments to quantify this signal and extract the signals which directly report on dose delivery will be completed to determine its value in verification, with a focus on whole breast radiotherapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB023909-03
Application #
9614991
Study Section
Biomedical Imaging Technology Study Section (BMIT)
Program Officer
Zubal, Ihor George
Project Start
2017-02-01
Project End
2020-12-31
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
3
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Engineering (All Types)
Type
Biomed Engr/Col Engr/Engr Sta
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755
Snyder, Clare; Pogue, Brian W; Jermyn, Michael et al. (2018) Algorithm development for intrafraction radiotherapy beam edge verification from Cherenkov imaging. J Med Imaging (Bellingham) 5:015001
LaRochelle, Ethan P M; Shell, Jennifer R; Gunn, Jason R et al. (2018) Signal intensity analysis and optimization for in vivo imaging of Cherenkov and excited luminescence. Phys Med Biol 63:085019
Miao, Tianshun; Bruza, Petr; Pogue, Brian W et al. (2018) Cherenkov imaging for linac beam shape analysis as a remote electronic quality assessment verification tool. Med Phys :
Bruza, Petr; Gollub, Sarah L; Andreozzi, Jacqueline M et al. (2018) Time-gated scintillator imaging for real-time optical surface dosimetry in total skin electron therapy. Phys Med Biol 63:095009