» Articles » PMID: 39677615

In Vivo, Online Label-free Monitoring of Heterogenous Oxygen Utilization During Phototherapy with Real-time Ultrasound-guided Photoacoustic Imaging

Overview
Journal bioRxiv
Date 2024 Dec 16
PMID 39677615
Authors
Affiliations
Soon will be listed here.
Abstract

Understanding the tumor microenvironment, particularly the vascular density and the availability of oxygen, is key in individualizing treatment approaches and determining their efficacy. While there are many therapies including radiotherapy that are ineffective in hypoxic tumor microenvironments, here we demonstrate the heterogeneous oxygen consumption during photodynamic therapy (PDT), a non-invasive treatment method using localized light to activate a photosensitive drug in the presence of oxygen that has shown high effectiveness in the treatment of various types of tumors, including those presented in head and neck cancer (HNC) patients. While our previous work has demonstrated that blood oxygen saturation (StO) mapped before and after treatment with ultrasound-guided photoacoustic imaging (US-PAI) can be used as a surrogate marker for the regionalized long-term efficacy of PDT, real-time monitoring of StO during PDT could provide additional insights on oxygen consumption and inform dose design for "on the spot" treatment decisions. Specifically, in this work, we integrated the US-PAI transducer probe with PDT light delivery fibers. We tested the setup on murine tumor models intravenously injected with liposomal benzoporphyrin derivative (BPD) photosensitizer at 0.5 mg/kg dose and photodynamic illumination at 100 and 400 mW/cm fluence rate. As expected, we observed with our US-PAI StO images that the rate of oxygen utilization increases when using a high fluence rate (HFR) light dose. Particularly in the higher fluence rate group, we observed StO reaching a minimum mid-light dose, followed by some degree of reoxygenation. US-PAI added the advantage of spatial information to StO monitoring, which allowed us to match regions of re-oxygenation during therapy to retained vascular function with immunohistochemistry. Overall, our results have demonstrated the potential of US-PAI for applications in online dosimetry for cancer therapies such as PDT, using oxygen changes to detect regionalized physiological vascular response in the tumor microenvironment.

References
1.
Vaupel P, Kallinowski F, Okunieff P . Blood flow, oxygen and nutrient supply, and metabolic microenvironment of human tumors: a review. Cancer Res. 1989; 49(23):6449-65. View

2.
Shao Q, Ashkenazi S . Photoacoustic lifetime imaging for direct in vivo tissue oxygen monitoring. J Biomed Opt. 2015; 20(3):036004. PMC: 4351645. DOI: 10.1117/1.JBO.20.3.036004. View

3.
Sweeney A, Arora A, Edwards S, Mallidi S . Ultrasound-guided photoacoustic image annotation toolkit in MATLAB (PHANTOM) for preclinical applications. Photoacoustics. 2024; 41:100662. PMC: 11648259. DOI: 10.1016/j.pacs.2024.100662. View

4.
Zhu Y, Xu G, Yuan J, Jo J, Gandikota G, Demirci H . Light Emitting Diodes based Photoacoustic Imaging and Potential Clinical Applications. Sci Rep. 2018; 8(1):9885. PMC: 6026116. DOI: 10.1038/s41598-018-28131-4. View

5.
van Leeuwen-van Zaane F, de Bruijn H, van der Ploeg-van den Heuvel A, Sterenborg H, Robinson D . The effect of fluence rate on the acute response of vessel diameter and red blood cell velocity during topical 5-aminolevulinic acid photodynamic therapy. Photodiagnosis Photodyn Ther. 2014; 11(2):71-81. DOI: 10.1016/j.pdpdt.2014.03.012. View