COVID-19 Information

MS Thesis Defense: Jennifer Soter

Monday, July 6, 2020, 10:00am

Videoconference

For info on how to attend this videoconference, please email jennifer.a.doter.TH@dartmouth.edu

“Development of Cherenkov-Excited Ink Imaging Platform for Novel Tumor Response Assay in Radiotherapy”

Abstract

Most techniques for tracking treatment progression in radiation therapy are anatomically based, measuring the size of the tumor through exams such as a weekly computed tomography (CT) scan. These can fail to detect subtle changes in tumor response at the cellular level that could provide useful insight, especially for combination therapies utilizing radiation. Therefore, there has been a recent emphasis towards functional imaging since it is widely recognized that changes to the tumor microenvironment including hypoxia and angiogenesis are strong indicators of treatment response. A number of functional imaging modalities including dynamic contrast-enhanced (DCE) imaging MRI, DCE ultrasound, perfusion CT or positron emission tomography (PET) are capable of characterizing biological processes that can better assess tumor microenvironmental responses and allow for the development of personalized treatment.

We hypothesized and tested the idea of using Cherenkov-excited luminescence imaging (CELI) to enable in vivo visualization of radiotherapy-induced tumor microstructural changes by tracking the diffusive spread of injected intratumoral phosphorescent tattoo ink. Using X-rays from a clinical linear accelerator to excite phosphorescent compounds within the tattoo ink, micro-liter quantities can be detected with a time-gated intensified CMOS camera. In this work, we first present a series of tissue-simulating phantom studies used to characterize the platform’s ability to image a selection of tattoo inks in a clinically relevant setting with CELI techniques. Next in a murine model using ex vivo hyperspectral cryo-fluorescence slice imaging to compare with in vivo CELI information, we showed that a diffusive spread of the injected tattoo ink after receiving a high dose of radiotherapy fraction could be related to radiation-induced necrosis, independent of total tumor volume change either due to edema or new cellular growth. CELI using phosphorescent tattoo ink offers the potential for a novel, minimally invasive radiotherapy response assay without interrupting a singular clinical workflow.

Thesis Committee

For more information, contact Daryl Laware at daryl.a.laware@dartmouth.edu.