Development and Validation of a Clinically Relevant Workflow for MR-Guided Volumetric Arc Therapy in a Rabbit Model of Head and Neck Cancer

Abstract

There is increased interest in the use of magnetic resonance imaging (MRI) for guiding radiation therapy (RT) in the clinical setting. In this regard, preclinical studies can play an important role in understanding the added value of MRI in RT planning. In the present study, we developed and validated a clinically relevant integrated workflow for MRI-guided volumetric arc therapy (VMAT) in a VX2 rabbit neck tumor model of HNSCC. In addition to demonstrating safety and feasibility, we examined the therapeutic impact of MR-guided VMAT using a single high dose to obtain proof-of-concept and compared the response to conventional 2D-RT. Contrast-enhanced MRI (CE-MRI) provided excellent soft tissue contrast for accurate tumor segmentation for VMAT. Notably, MRI-guided RT enabled improved tumor targeting ability and minimal dose to organs at risk (OAR) compared to 2D-RT, which resulted in notable morbidity within a few weeks of RT. Our results highlight the value of integrating MRI into the workflow for VMAT for improved delineation of tumor anatomy and optimal treatment planning. The model combined with the multimodal imaging approach can serve as a valuable platform for the conduct of preclinical RT trials.

Animal Models for Radiotherapy Research: All (Animal) Models Are Wrong but Some Are Useful

“…Their study explores the use of a clinical fiducial marker in small animal image guided-radiotherapy (IGRT), demonstrating BioXmark as a tool to improve target delineation and reduce set-up errors with minimal impacts on the radiobiological response. Another powerful example of reverse translation is provided by Bolookat [ 7 ] who reports an integrated workflow for MRI-guided volumetric arc therapy (VMAT) in a rabbit tumour model of HNSCC. This study demonstrates the feasibility of developing a clinically-relevant workflow in a laboratory, with potential applications to examine long-term survival and evaluate disease recurrence with MR-guided VMAT.…”

Ultrasound-Guided Photoacoustic Imaging of Salivary Gland Hemodynamics in Rabbits

“…Nevertheless, our results provide important proof-of-concept to highlight the translational utility of US-guided PAI as a valuable tool for visualization of the salivary gland anatomy and functional imaging of the vascularity and oxygenation without the need for radioisotopes or intravenous contrast agents. We are currently examining the potential of integrating PAI into a clinically relevant workflow of image-guided RT, developed by us [22]. We are also focused on validating PAI-based measures of tumor and salivary gland vascular response to RT with magnetic resonance imaging (MRI) in rabbits.…”