2245 - A Universal Bioluminescence Tomography-Guided System for Pre-Clinical Radiotherapy Research
Presenter(s)
Z. Tong1, X. Xu1, Z. Deng1, C. Newman1, X. Jia2, Y. Zhong2, A. M. Reinhart3, T. Devling3, H. Dehghani4, I. Iordachita5, D. Saha6, J. W. Wong2, and K. K. H. Wang1; 1Biomedical Imaging and Radiation Technology Laboratory (BIRTLab), Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, 2Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, 3Xstrahl Inc., Suwanee, GA, 4School of Computer Science, University of Birmingham, Birmingham, United Kingdom, 5Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 6Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX
Purpose/Objective(s): Widely used cone-beam computed tomography (CBCT)-guided small animal irradiators are limited to localize soft-tissue targets due to low imaging contrast. While bioluminescence tomography (BLT) offers a promising solution, its adoption has been limited. To address this, we developed MuriGlo, a universal BLT system that integrates with irradiators for image-guided studies. We demonstrated MuriGlo’s capabilities in supporting both in vitro and in vivo experiments.
Materials/Methods: MuriGlo consists of 4 mirrors, a detachable mouse bed, thermostatic control, filters, lens, and charge-coupled device (CCD) camera, enabling a compact imaging platform capable of multi-projection and multi-spectral imaging. The bed allows the transfer of animals between MuriGlo and irradiators for BLT-guided irradiation. We evaluated the thermostatic control’s ability to maintain consistent animal body temperature. We also quantified system sensitivity through the signal-to-noise ratio (SNR) in detecting minimal cell quantities using glioblastoma (GL261) cells with Luc2 and AkaLuc reporters. To demonstrate image-guided capabilities, we evaluated the tumor localization accuracy of BLT using the orthotopic GBM model by calculating the center of mass (CoM) deviation between the BLT-reconstructed GTV (GTVBLT) and the ground-truth GTV (delineated from MRI). To account for the uncertainty of GTVBLT in target positioning and volume delineation, a margin of 0.75mm was added to GTVBLT to form a PTV (PTVBLT) used for planning. We represent BLT-guided 5-arc and 2-field box, and BLI-guided single-field plans and their use for effective in vivo studies. Moreover, we compared MuriGlo's tumor localization accuracy applied to guide SARRP and SmART+ irradiation.
Results: The thermostatic control sustains animal temperature at 37°C throughout imaging. The optical system can detect as few as 61 GL261-AkaLuc cells in vitro at SNR=5. The high-conformal BLT-guided 5-arc plan fully covers the GTV at the prescribed dose with minimal normal tissue exposure, whereas the simplified, high-throughput BLT-guided 2-field box achieves 100% GTV coverage but results in larger normal tissue exposure. Tumor localization accuracy of MuriGlo for both SARRP and SmART+ is <1mm, with no statistically significant difference. The GTV coverage exceeds 97% for both irradiators using the reconstructed PTVBLT.
Conclusion: The universal BLT-guided system offers seamless integration with commercial irradiators, achieving comparable localization accuracy, expected to support high-precision radiation research.