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Hard x-ray bio imaging

Our research

Senior scientist(s): Hans Hertz, Anna Burvall

X-ray imaging technologies are essential for life science, from basic research to clinical practice. Novel modalities such as, e.g., phase-contrast imaging [1], shows promise for higher spatial resolution and improved contrast while still operating with an acceptable dose. Many imaging methods are source limited.

We invented the liquid-metal-jet-anode hard x-ray source [2]. This compact electron-impact microfocus source potentially allows for more than 100´ higher brightness than any competing laboratory x-ray tube. We exploit the unique high spatial coherence of the source for very-high-resolution propagation-based phase-contrast imaging at low dose [3]. Past projects include, e.g., microangiography in mouse, demonstrating detection of sub-10 mm diam vessels. The method was also extended to imaging of intact tumor microvasculature (cf. Fig. 1) [4] as well as to whole-body mouse CT. Current projects are:

Propagation-based phase-contrast imaging

Present work focuses on high-resolution soft-tissue imaging [5,6] and phase retrieval [7]. A recent study concerned imaging of ancient tissue in the form of a 2500 years old mummy hand (see Fig. 2) [8]. Simulations of realistic imaging for medical applications are also developed [9].

Fig. 2. Left: mummy hand and visualization of bones and blood vessels in the nail bed. Right: tomographic slice of finger tip showing the well preserved tissue.

X-ray fluorescence tomography

X-ray fluorescence (XRF) is used for 3D molecular imaging. We have developted a laboratory system for high-resolution imaging of small animals [10].

Fig. 3. Nanoparticle distribution in mice for five different intervals between injection and imaging. Absorption signal in gray and fluorescence signal in color.

Prospective students

We have master thesis projects available in both phase-contrast imaging and XRF. For more information, please contact Hans Hertz at hans.hertz@biox.kth.se.

References

  1. See, e.g., F. Pfeiffer et. al, Natute Phys 2, 258 (2006).
  2. O. Hemberg et al, Appl. Phys. Lett. 83, 1483 (2003).
  3. T. Tiuhimaa et al, Appl. Phys. Lett. 91, 074104 (2007).
  4. U. Lundstrom et al, Phys Med Biol. 59, 2801-11 (2014).
  5. W. Vågberg et al, Sci Rep. 5, 16625 (2015).
  6. W. Vågberg et al, Sci Rep. 8, 11014 (2018) .
  7. I. Häggmark et al, Opt. Express 25, 33543 (2017) .
  8. J. Romell et al, Radiology 289, 670-676 (2018) .
  9. I. Häggmark et al, IEEE TMI 40, 539-548 (2021) .
  10. K. Shaker et al, IEEE TMI 39, 3910-3919 (2020) .