Boards, Advisory Committees, Professional Organizations

  • Global Health Postdoctoral Affiliate, Center for Innovation in Global Health (CIGH) (2023 - Present)

Stanford Advisors

All Publications

  • Organ uptake, toxicity and skin clearance of ruthenium contrast agents monitored in vivo by x-ray fluorescence NANOMEDICINE Vogt, C., Saladino, G. M., Shaker, K., Arsenian-Henriksson, M., Hertz, H. M., Toprak, M. S., Brodin, B. A. 2023


    Aims: To investigate the distribution and toxicity of ruthenium nanoparticles (Ru NPs) injected intravenously in mice. Methods: We synthesized Ru NPs, followed their biodistribution by x-ray fluorescence (XRF) imaging and evaluated organ toxicity by histopathology and gene expression. Results: Ru NPs accumulated, mainly in liver and spleen, where they were phagocyted by tissue macrophages, giving a transient inflammation and oxidative stress response that declined after 2 weeks. Ru NPs gradually accumulated in the skin, which was confirmed by microscopic examination of skin biopsies. Conclusion: Ru NP toxicity in recipient organs is transient. Particles are at least partially excreted by the skin, supporting a role for the skin as a nanoparticle clearing organ.

    View details for DOI 10.2217/nnm-2023-0061

    View details for Web of Science ID 001061631900001

    View details for PubMedID 37665018

  • Phase-contrast virtual chest radiography. Proceedings of the National Academy of Sciences of the United States of America Haggmark, I., Shaker, K., Nyren, S., Al-Amiry, B., Abadi, E., P Segars, W., Samei, E., M Hertz, H. 2023; 120 (1): e2210214120


    Respiratory X-ray imaging enhanced by phase contrast has shown improved airway visualization in animal models. Limitations in current X-ray technology have nevertheless hindered clinical translation, leaving the potential clinical impact an open question. Here, we explore phase-contrast chest radiography in a realistic in silico framework. Specifically, we use preprocessed virtual patients to generate in silico chest radiographs by Fresnel-diffraction simulations of X-ray wave propagation. Following a reader study conducted with clinical radiologists, we predict that phase-contrast edge enhancement will have a negligible impact on improving solitary pulmonary nodule detection (6 to 20 mm). However, edge enhancement of bronchial walls visualizes small airways (< 2 mm), which are invisible in conventional radiography. Our results show that phase-contrast chest radiography could play a future role in observing small-airway obstruction (e.g., relevant for asthma or early-stage chronic obstructive pulmonary disease), which cannot be directly visualized using current clinical methods, thereby motivating the experimental development needed for clinical translation. Finally, we discuss quantitative requirements on distances and X-ray source/detector specifications for clinical implementation of phase-contrast chest radiography.

    View details for DOI 10.1073/pnas.2210214120

    View details for PubMedID 36580596