Low-dose phase contrast x-ray medical imaging

Abstract

Phase contrast x-ray imaging is a powerful technique for the detection of low-contrast details in weakly absorbing objects. This method is of possible relevance in the field of diagnostic radiology. In fact, imaging low-contrast details within soft tissue does not give satisfactory results in conventional x-ray absorption radiology, mammography being a typical example. Nevertheless, up to now all applications of the phase contrast technique, carried out on thin samples, have required radiation doses substantially higher than those delivered in conventional radiological examinations. To demonstrate the applicability of the method to mammography we produced phase contrast images of objects a few centimetres thick while delivering radiation doses lower than or comparable to doses needed in standard mammographic examinations (typically approximately 1 mGy mean glandular dose (MGD)). We show images of a custom mammographic phantom and of two specimens of human breast tissue obtained at the SYRMEP bending magnet beamline at Elettra, the Trieste synchrotron radiation facility. The introduction of an intensifier screen enabled us to obtain phase contrast images of these thick samples with radiation doses comparable to those used in mammography. Low absorbing details such as 50 microm thick nylon wires or thin calcium deposits (approximately 50 microm) within breast tissue, invisible with conventional techniques, are detected by means of the proposed method. We also find that the use of a bending magnet radiation source relaxes the previously reported requirements on source size for phase contrast imaging. Finally, the consistency of the results has been checked by theoretical simulations carried out for the purposes of this experiment.

The SYRMEP Beamline of Elettra: Clinical Mammography and Bio-medical Applications

“…Among the phase sensitive techniques, PhC imaging requires the simplest experimental set-up that is implemented choosing an adequate distance between the sample and the detector [1]. For this reason, the major effort of our research team has been oriented to study the effectiveness of PhC imaging using test objects and human breast tissue specimens [1,2,5].…”

“…At the SYRMEP beamline of Elettra, a widespread research activity in bio-medical imaging has been developed since 1997 [1]. Besides conventional absorption imaging, phase-sensitive techniques such as free propagation Phase Contrast (PhC) and AnalyzerBased Imaging (ABI) have been applied to various contexts of bio-medical imaging.…”

3D angioarchitecture changes after spinal cord injury in rats using synchrotron radiation phase-contrast tomography

“…9 Unlike conventional attenuation-based X-ray imaging, PCI utilizes a unique refraction-based contrast mechanism that is suitable for the detection of soft biological tissue. 10 Using a conventional X-ray tube source, PCI achieves better contrast in soft-tissue than conventional attenuation approaches. [11][12][13] With the rapid development of X-ray sources of high tuneability, brightness and monochromaticity, the development of a new generation of X-ray imaging systems for medical applications has been stimulated.…”

Clinical study in phase- contrast mammography: image-quality analysis

“…The analysis of the first group of patients produced promising preliminary results reported in [1][2][3]. Propagation-based phase-contrast imaging (PPCI) [4] was applied, based on the high coherence of the synchrotron radiation (SR) beam. In fact, albeit other phase-sensitive techniques were successfully experimented in in vitro mammography [5][6][7][8], PPCI was preferred because of its simplicity in the experimental set-up, that allowed a straightforward translation to the in vivo application.…”