Towards breast tomography with synchrotron radiation at Elettra: first images

Abstract

The aim of the SYRMA-CT collaboration is to set-up the first clinical trial of phase-contrast breast CT with synchrotron radiation (SR). In order to combine high image quality and low delivered dose a number of innovative elements are merged: a CdTe single photon counting detector, state-of-the-art CT reconstruction and phase retrieval algorithms. To facilitate an accurate exam optimization, a Monte Carlo model was developed for dose calculation using GEANT4. In this study, high isotropic spatial resolution (120 μm)(3) CT scans of objects with dimensions and attenuation similar to a human breast were acquired, delivering mean glandular doses in the range of those delivered in clinical breast CT (5-25 mGy). Due to the spatial coherence of the SR beam and the long distance between sample and detector, the images contain, not only absorption, but also phase information from the samples. The application of a phase-retrieval procedure increases the contrast-to-noise ratio of the tomographic images, while the contrast remains almost constant. After applying the simultaneous algebraic reconstruction technique to low-dose phase-retrieved data sets (about 5 mGy) with a reduced number of projections, the spatial resolution was found to be equal to filtered back projection utilizing a four fold higher dose, while the contrast-to-noise ratio was reduced by 30%. These first results indicate the feasibility of clinical breast CT with SR.

Propagation‐based x‐ray phase‐contrast tomography of mastectomy samples using synchrotron radiation

“…The assessment results by the imaging experts and radiologists were found to be generally consistent with the objective measurements of SNR and spatial resolution in the reconstructed CT slices of mastectomy samples. These results constitute part of the systematic research that our collaborative team has been conducting with the goal of developing medical breast cancer imaging facilities at the Australian Synchrotron in Melbourne, Australia, and at Elettra Synchrotron in Trieste, Italy …”

“…These results constitute part of the systematic research that our collaborative team has was assessed as having higher quality, even though the measured signal-to-noise-ratio and spatial resolution were apparently better in image (a) (see Table II) been conducting with the goal of developing medical breast cancer imaging facilities at the Australian Synchrotron in Melbourne, Australia, and at Elettra Synchrotron in Trieste, Italy. 11,15,25,27,40…”

“…The microfocus x‐ray source technology is currently at a stage where it still cannot deliver x‐ray illumination of sufficient spatial coherence with a brightness (x‐ray flux) that would enable CT scans of a full human breast within a clinically acceptable time. Recent work on the development of PB‐CT technology for breast cancer imaging of live human patients has been concentrated at synchrotron facilities, especially at Elettra synchrotron in Trieste, Italy and at the Australian Synchrotron in Melbourne . In the present paper, we describe some of the latest results obtained in the process of development of breast PB‐CT imaging facility at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron …”

Evaluation of theBreastSimulatorsoftware platform for breast tomography

“…CT scans for mono-energetic beams with photon energies of 32 keV, 43 keV and 51 keV were simulated, since these energies correspond to the mean energy of the poly-energetic spectra at 49, 60 and 80 kVp, respectively. On the other hand, mono-energetic beams at 27 keV and 35 keV have a photon energy close to those used in the experimental studies ongoing at the Elettra synchrotron radiation facility on phase-contrast BCT [Longo et al 2016]. …”

“…On the other hand, cone-beam computed tomography (CT) scanners dedicated to the uncompressed breast (breast CT, BCT) are available either experimentally or commercially, characterized by the use of quasi-mono-energetic [McKinley et al 2005] or poly-energetic X-ray beams [Lindfords et al 2008; O’Connell et al 2010; Kalender et al 2012; Russo et al 2010; Mettivier et al 2011; Sarno et al 2015, 2016a]. Parallel-beam synchrotron radiation mono-energetic BCT is also under investigation [Longo et al 2016; Mettivier et al 2016; Sarno et al 2016b]. But before the BCT can become a clinical procedure a number of issues should be optimized, such as the source and the detector design [Kalender et al 2012], the acquisition strategy [Linfords et al 2008; McKinley et al 2012], the reconstruction methods.…”