Laser-wakefield accelerators as hard x-ray sources for 3D medical imaging of human bone

Abstract

A bright μm-sized source of hard synchrotron x-rays (critical energy Ecrit > 30 keV) based on the betatron oscillations of laser wakefield accelerated electrons has been developed. The potential of this source for medical imaging was demonstrated by performing micro-computed tomography of a human femoral trabecular bone sample, allowing full 3D reconstruction to a resolution below 50 μm. The use of a 1 cm long wakefield accelerator means that the length of the beamline (excluding the laser) is dominated by the x-ray imaging distances rather than the electron acceleration distances. The source possesses high peak brightness, which allows each image to be recorded with a single exposure and reduces the time required for a full tomographic scan. These properties make this an interesting laboratory source for many tomographic imaging applications.

Observation of Betatron X-Ray Radiation in a Self-Modulated Laser Wakefield Accelerator Driven with Picosecond Laser Pulses

“…A source based on betatron emission from a laserplasma accelerator [1] is attractive for this purpose because it generates a small-divergence , broadband x-ray beam that can be used to backlight the target being studied. Betatron x-ray radiation has been used for biological and medical purposes, such as x-ray phase contrast imaging of insects [2][3][4] and hard x-ray radiography of bone [5]. Its unique properties also make it suitable for studying the dynamics of high-energy-density plasmas and warm dense matter, a state near solid densities,…”

Coupling Effects in Multistage Laser Wake-field Acceleration of Electrons

“…Laser wake field acceleration (LWFA) of electrons is one of the rapidly developed scientific fields for the last decade [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. This technique, providing potentially jitter-free sources of radiation and electrons, has already demonstrated the electron acceleration over 4 GeV [13] in a single stage with laser pulse energy less than 100 J.…”

High-resolution Tomographic Imaging Using Coherent Hard x-rays From Compact Laser Driven Accelerators

“…The electrons generate a broad polychromatic x-ray spectrum with a critical energy up to 50 keV (similar to a synchrotron spectrum) and a peak brightness comparable with large-scale synchrotron light sources. This provides sufficient intensity to obtain an image using a single pulse [2] and so the image acquisition rate is limited only by the repetition rate of the drive laser pulses. The increase in repetition rate of petawatt lasers to 10 Hz in the near future opens up exciting possibilities for applying these extremely bright compact sources for research, pre-clinical and clinical imaging.…”

“…2(d) shows the 3D reconstruction of a human femoral trabecular bone sample (Fig 2. (c)) with a resolution below 50 µm [2]. More recently we have taken hard x-ray absorption images of mouse embryos at 0.5 degree intervals (not shown).…”