Mono-Energy Coronary Angiography with a Compact Synchrotron Source

Abstract

X-ray coronary angiography is an invaluable tool for the diagnosis of coronary artery disease. However, the use of iodine-based contrast media can be contraindicated for patients who present with chronic renal insufficiency or with severe iodine allergy. These patients could benefit from a reduced contrast agent concentration, possibly achieved through application of a mono-energetic x-ray beam. While large-scale synchrotrons are impractical for daily clinical use, the technology of compact synchrotron sources strongly advanced during the last decade. Here we present a quantitative analysis of the benefits a compact synchrotron source can offer in coronary angiography. Simulated projection data from quasi-mono-energetic and conventional x-ray tube spectra is used for a CNR comparison. Results show that compact synchrotron spectra would allow for a significant reduction of contrast media. Experimentally, we demonstrate the feasibility of coronary angiography at the Munich Compact Light Source, the first commercial installation of a compact synchrotron source.X-ray imaging is an invaluable diagnostic tool in clinical practice. While conventional x-ray tubes are well established and reliable in clinical x-ray imaging, their broad bremsstrahlung spectra impose a number of drawbacks with respect to image quality. The polychromatic spectrum can introduce beam hardening artifacts or impede the aim to optimize both the dose level and the image quality, as the x-ray energy cannot be tuned directly to the desired range. On the other hand, 3rd generation synchrotron sources offer highly brilliant and monochromatic x-ray beams, but their high spatial and financial demands make their clinical use impracticable. To close this performance gap, new types of x-ray sources have been investigated throughout the last decades. One possibility are compact light sources (CLS) based on inverse Compton scattering 1 , which provide a quasi-mono-energetic, tunable and partially coherent x-ray beam. The first commercially sold system has only recently been installed in Munich, Germany 2 .One of the clinical applications that could benefit significantly from a mono-energetic x-ray beam is coronary angiography, as it relies on contrast media application. A mono-energetic x-ray beam could thoroughly exploit the sudden increase of the absorption coefficient of a contrast medium at its K-edge.Coronary angiography is an invaluable tool for the diagnosis of coronary disease. Complications are frequently associated with the high amount of iodine-based contrast media that are injected during the catheterization procedure. Especially for patients presenting with pre-existing renal insufficiency, there is a high risk to suffer from renal failure due to nephrotoxic effects of iodine-based contrast agents, resulting in severe renal dysfunction and a high risk of subsequent dialysis treatment 3-6 . In addition, several patients show allergic reactions following iodine injection, with the life-threatening risk of anaphylaxis 6 . A high amount of iodine c...

A compact light source providing high-flux, quasi-monochromatic, tunable X-rays in the laboratory

“…Given the biomedical imaging research focus of the TUM group, a large number of application examples has been generated in this area. 8,[10][11][12][13][14][15][16][17][18][21][22][23][24][25][26][28][29][30][31] While earlier experiments focused on demonstrating different X-ray imaging techniques on the CLS, such as mono-energy X-ray absorption tomography, grating-based multimodal imaging, propagation-based phase contrast and phase contrast tomography, these are now applied to specific biomedical applications and extended to advanced techniques, such as dynamic imaging, K-edge subtraction imaging and others.…”

“…19,20 The MuCLS has been operating with a high degree of uptime since then and has enabled many scientific experiments and publications. [21][22][23][24][25][26][27][28][29][30][31] Generally, most X-ray techniques such as diffraction, imaging, spectroscopy or scattering can be performed with both electron-impact and synchrotron sources. While the details depend on the technique and the specific application needs, generally the following guidelines apply: Longer measurement times Shorter measurement times Lower resolution and sensitivity Higher resolution and sensitivity Suitable where fixed energy or polychromatic beam is acceptable Required where tunability and/or monochromaticity is required Advantageous for large sample sizes (e.g., imaging of large components and low or moderate resolution)…”

The Munich Compact Light Source: Biomedical Research At a Laboratory-Scale Inverse-Compton Synchrotron X-ray Source

“…Simultaneously providing a much smaller footprint and being cost-effective compared to the latter, ICS overcome the main limitations for widespread application of advanced imaging techniques in industry and health care. This makes the MuCLS well-suited for various applications in biomedical imaging [2][3][4][5][6], on which we will focus here after a brief review of recent source development at the MuCLS.…”

“…In combination with the high brilliance and partial coherence of the MuCLS, this enables the study of many topics of biomedical interest. We present our research in the fields of angiography [4] and (dynamic) K-edge subtraction imaging, detection of micro-fractures [5], phase-contrast imaging applied to mammography, as well as in vivo small-animal respiratory imaging [6]. We are able to demonstrate superior image quality and diagnostic value compared to state of the art clinical procedures and to transfer techniques that have so far been limited to large-scale synchrotron facilities, like dynamic small-animal respiratory imaging, shown in Figure 2, into a laboratory.…”

Two-colour X-gamma ray inverse Compton back-scattering source

“…Thomson and Compton sources, even though less brilliant than FELs, produce radiation with short wavelength, high power, ultrashort time duration, large transverse coherence and tunability, full polarization control, ensuring limited costs of construction and maintenance and dimensions compatible with the space that can be allocated in hospitals and medical centres. Existing Thomson sources [14][15][16][17][18][19][20][21] are important tools for generating tunable quasimonochromatic X/gamma rays suitable for applications in crystallography, plasma, high energy, matter physics and nuclear photonics and in the advanced biomedical imaging as demonstrated by the wide number of experiments on phase contrast imaging [18,22], microtomography [22], K-edge techniques [13,23] on biological and human samples. In this paper we present a simple and new scheme for producing two-colour Thomson/Compton radiation with the possibility of controlling independently the polarization of the two beamlets.…”