Spectral Cherenkov Imaging for Quantitative Dosimetry and Physiological Monitoring of Radiation Therapy - Project Summary: Radiation therapy is a continually expanding field with a growing development of complex treatment techniques, all of which require precise dosimetric and physical verification of delivery. Various approaches have been developed to address the need for such real-time surface dose verification, but they rely on foreign materials to serve as dose analogs through charge, energy trapping, or chemical effects and do not fully satisfy the conditions for real-time, full-field and non-invasive monitoring. However, during electron or photon therapy, a low light signal called the “Cherenkov effect” is generated within the patient's tissue and can be collected using specialized imaging techniques developed by Dartmouth College and DoseOptics LLC. Cherenkov imaging has proven to be a valuable tool for qualitative monitoring of radiation delivery, while directly referencing patient surface anatomy. Several studies have demonstrated its efficacy in treatment verification and identifying delivery errors, making it the first technique to address the otherwise “blind” nature of radiation therapy. The generated Cherenkov light is fundamentally proportional to the delivered dose, and as it travels through superficial tissue, it adopts the local tissue characteristics. This allows Cherenkov imaging to offer real- time, full-field, non-invasive dosimetry while reflecting subsurface tissue composition, such as early onset of skin toxicity or fluctuation in tissue oxygenation in response to therapy. However, the emitted light also undergoes spectral attenuation which disrupts the direct relationship between intensity and dose. While the promise of this technique is revolutionary to radiotherapy dosimetry, the relationship between intensity and dose must be retained to utilize its full potential. This proposed research aims to develop, test, and clinically translate spectral Cherenkov imaging, ultimately creating a spectral correction algorithm for clinical imaging. This would transform Cherenkov imaging into a comprehensive dosimetry tool and enable inter-fractional monitoring of physiological development in response to therapy regardless of patient composition. This will be achieved through collaboration between the Thayer School of Engineering, DHMC, and DoseOptics LLC, together establishing a nurturing research and clinical environment with adequate hardware and software support for successful development. Upon completion, this work will establish Cherenkov imaging as a viable real-time dosimetry tool and expand its efficacy to proactive monitoring and identification of tissue response. The training objectives aim to bridge the gap between exploratory research and clinical translation in optical dosimetry, broaden their knowledge of medical physics, and develop the clinical and technical skills necessary for a successful career as a medical physicist. The applicant will pursue professional development through workshops, literature review, research presentations, mentorship, academic instruction, and authoring peer-reviewed articles. With support from sponsors and collaborators, this fellowship will advance the applicant toward a successful career in medical physics, contributing meaningful research for the entirety of their career.
