Browsing by Author "Taba, ST"
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- ItemComparison of propagation-based phase-contrast CT and absorption-based CT for breast imaging using synchrotron radiation(Society of Photo-Optical Instrumentation Engineers (SPIE), 2020-05-22) Taba, ST; Lewis, S; Baran, PM; Arhatari, BD; Nesterets, YI; Mayo, SC; Thompson, D; Fox, J; Kumar, B; Prodanovic, Z; Häusermann, D; Masimenko, A; Hall, CJ; Dimmock, M; Pavlov, KM; Peele, AG; Quiney, HM; Lockie, D; Tromba, G; Gureyev, TE; Brennan, PCPropagation-based phase-contrast CT (PB-CT) is a novel imaging technique that visualises variations in both X-ray attenuation and refraction. This study aimed to compare the clinical image quality of breast PB-CT using synchrotron radiation with conventional absorption-based CT (AB-CT), at the same radiation dose. Seven breast mastectomy specimens were scanned and evaluated by a group of 14 radiologists and medical imaging experts who assessed the images based on seven radiological image quality criteria. Visual grading characteristics (VGC) were used to analyse the results and the area under the VGC curve was obtained to measure the differences between the two techniques. For six image quality criteria (overall quality, perceptible contrast, lesion sharpness, normal tissue interfaces, calcification visibility and image noise), PB-CT images were superior to AB-CT images of the same dose (AUCVGC: 0.704 to 0.914, P≤.05). For the seventh criteria (artefacts), PB-CT images were also rated better than AB-CT images (AUCVGC: 0.647) but the difference was not significant. The results of this study provide a solid basis for future experimental and clinical protocols of breast PB-CT. © 2020 Society of Photo-Optical Instrumentation Engineers (SPIE).
- ItemEffect of x-ray energy on the radiological image quality in propagation-based phase-contrast computed tomography of the breast(Society of Photo-Optical Instrumentation Engineers (SPIE), 2021-07-12) Wan, S; Arhatari, BD; Nesterets, YI; Mayo, SC; Thompson, D; Fox, J; Kumar, B; Prodanovic, Z; Häusermann, D; Maksimenko, A; Hall, CJ; Dimmock, MR; Pavlov, KM; Lockie, D; Rickard, M; Gadomkar, Z; Alaleh, A; Vafa, E; Peele, AG; Quiney, HM; Lewis, SJ; Gureyev, TE; Brennan, PC; Taba, STPurpose: Breast cancer is the most common cancer in women in developing and developed countries and is responsible for 15% of women’s cancer deaths worldwide. Conventional absorption-based breast imaging techniques lack sufficient contrast for comprehensive diagnosis. Propagation-based phase-contrast computed tomography (PB-CT) is a developing technique that exploits a more contrast-sensitive property of x-rays: x-ray refraction. X-ray absorption, refraction, and contrast-to-noise in the corresponding images depend on the x-ray energy used, for the same/fixed radiation dose. The aim of this paper is to explore the relationship between x-ray energy and radiological image quality in PB-CT imaging. Approach: Thirty-nine mastectomy samples were scanned at the imaging and medical beamline at the Australian Synchrotron. Samples were scanned at various x-ray energies of 26, 28, 30, 32, 34, and 60 keV using a Hamamatsu Flat Panel detector at the same object-to-detector distance of 6 m and mean glandular dose of 4 mGy. A total of 132 image sets were produced for analysis. Seven observers rated PB-CT images against absorption-based CT (AB-CT) images of the same samples on a five-point scale. A visual grading characteristics (VGC) study was used to determine the difference in image quality. Results: PB-CT images produced at 28, 30, 32, and 34 keV x-ray energies demonstrated statistically significant higher image quality than reference AB-CT images. The optimum x-ray energy, 30 keV, displayed the largest area under the curve ( AUCVGC ) of 0.754 (p = 0.009). This was followed by 32 keV (AUCVGC = 0.731, p ≤ 0.001), 34 keV (AUCVGC = 0.723, p ≤ 0.001), and 28 keV (AUCVGC = 0.654, p = 0.015). Conclusions: An optimum energy range (around 30 keV) in the PB-CT technique allows for higher image quality at a dose comparable to conventional mammographic techniques. This results in improved radiological image quality compared with conventional techniques, which may ultimately lead to higher diagnostic efficacy and a reduction in breast cancer mortalities.. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).
- ItemEnergy optimisation of propagation-based phase-contrast computed tomography: a quantitative image quality assessment(SPIE, 2022-04-04) Lim, B; Lewis, S; Arhatari, BD; Nesterets, YI; Mayo, SC; Fox, J; Thomposon, D; Kumar, B; Häusermann, D; Maksimenko, A; Hall, C; Dimmock, M; Lockie, D; Rickard, M; Giannoitti, N; Peele, AG; Quiney, HM; Gureyev, TE; Brennan, PC; Taba, STPurpose: This study aims at establishing the optimum x-ray energy for synchrotron acquired propagation-based computed tomography (PB-CT) images to obtain highest radiological image quality of breast mastectomy samples. It also examines the correlation between objective physical measures of image quality with subjective human observer scores to model factors impacting visual determinants of image quality. Approach: Thirty mastectomy samples were scanned at Australian Synchrotron’s Imaging and Medical Beamline. Samples were scanned at energies of 26, 28, 30, 32, 34, and 60 keV at a standard dose of 4mGy. Objective physical measures of image quality were assessed using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), SNR/resolution (SNR/res), CNR/resolution (CNR/res) and visibility. Additional calculations for each measure were performed against reference absorption-based computer tomography (AB-CT) images scanned at 32 keV and 4mGy. This included differences in SNR (dSNR), CNR (dCNR), SNR/res (dSNR/res), CNR/res (dCNR/res), and visibility (dVis). Physical measures of image quality were also compared with visual grading analysis data to determine a correlation between observer scores and objective metrics. Results: For dSNR, dCNR, dSNR/res, dCNR/res, and dVis, a statistically significant difference was found between the energy levels. The peak x-ray energy for dSNR and dSNR/res was 60 keV. For dCNR and dCNR/res 34 keV produced the highest measure compared to 28 keV for dVis. Visibility and CNR correlate to 56.8% of observer scores. Conclusion: The optimal x-ray energy differs for different objective measures of image quality with 30-34 keV providing optimum image quality for breast PB-CT. Visibility and CNR correlate highest to medical imaging expert scores. © (2022) Society of Photo-Optical Instrumentation Engineers (SPIE).
- ItemImaging breast microcalcifications using dark-field signal in propagation-based phase-contrast tomography(IEEE, 2022-05-18) Aminzadeh, A; Arhatari, BD; Maksimenko, A; Hall, CJ; Häusermann, D; Peele, AG; Fox, J; Kumar, B; Prodanovic, Z; Dimmock, MR; Lockie, D; Pavlov, KM; Nesterets, YI; Thompson, D; Mayo, SC; Paganin, DM; Taba, ST; Lewis, SJ; Brennan, PC; Quiney, HM; Gureyev, TEBreast microcalcifications are an important primary radiological indicator of breast cancer. However, microcalcification classification and diagnosis may be still challenging for radiologists due to limitations of the standard 2D mammography technique, including spatial and contrast resolution. In this study, we propose an approach to improve the detection of microcalcifications in propagation-based phase-contrast X-ray computed tomography of breast tissues. Five fresh mastectomies containing microcalcifications were scanned at different X-ray energies and radiation doses using synchrotron radiation. Both bright-field (i.e. conventional phase-retrieved images) and dark-field images were extracted from the same data sets using different image processing methods. A quantitative analysis was performed in terms of visibility and contrast-to-noise ratio of microcalcifications. The results show that while the signal-to-noise and the contrast-to-noise ratios are lower, the visibility of the microcalcifications is more than two times higher in the dark-field images compared to the bright-field images. Dark-field images have also provided more accurate information about the size and shape of the microcalcifications. © 2023 IEEE
- ItemPropagation-based phase-contrast CT of the breast demonstrates higher quality than conventional absorption-based CT even at lower radiation dose(Elsevier B. V., 2021-01) Taba, ST; Arhatari, BD; Nesterets, YI; Gadomkar, Z; Mayo, SC; Thompson, D; Fox, J; Kumar, B; Prodanovic, Z; Häusermann, D; Maksimenko, A; Hall, CJ; Dimmock, MR; Pavlov, KM; Lockie, D; Gity, M; Peele, AG; Quiney, HM; Lewis, SJ; Gureyev, TE; Brennan, PCRationale and Objectives Propagation-based phase-contrast CT (PB-CT) is an advanced X-ray imaging technology that exploits both refraction and absorption of the transmitted X-ray beam. This study was aimed at optimizing the experimental conditions of PB-CT for breast cancer imaging and examined its performance relative to conventional absorption-based CT (AB-CT) in terms of image quality and radiation dose. Materials and Methods Surgically excised breast mastectomy specimens (n = 12) were scanned using both PB-CT and AB-CT techniques under varying imaging conditions. To evaluate the radiological image quality, visual grading characteristics (VGC) analysis was used in which 11 breast specialist radiologists compared the overall image quality of PB-CT images with respect to the corresponding AB-CT images. The area under the VGC curve was calculated to measure the differences between PB-CT and AB-CT images. Results The highest radiological quality was obtained for PB-CT images using a 32 keV energy X-ray beam and by applying the Homogeneous Transport of Intensity Equation phase retrieval with the value of its parameter γ set to one-half of the theoretically optimal value for the given materials. Using these optimized conditions, the image quality of PB-CT images obtained at 4 mGy and 2 mGy mean glandular dose was significantly higher than AB-CT images at 4 mGy (AUCVGC = 0.901, p = 0.001 and AUCVGC = 0.819, p = 0.011, respectively). Conclusion PB-CT achieves a higher radiological image quality compared to AB-CT even at a considerably lower mean glandular dose. Successful translation of the PB-CT technique for breast cancer imaging can potentially result in improved breast cancer diagnosis. Crown Copyright © 2020 Published by Elsevier Inc. on behalf of The Association of University Radiologists.
- ItemPropagation-based x-ray phase-contrast tomography of mastectomy samples using synchrotron radiation(American Association of Physicists in Medicine, 2019-10-01) Gureyev, TE; Nesterets, YI; Baran, PM; Taba, ST; Mayo, SC; Thompson, D; Arhatari, BD; Mihocic, A; Abbey, B; Lockie, D; Fox, J; Kumar, B; Prodanovic, Z; Häusermann, D; Maksimenko, A; Hall, CJ; Peele, AG; Dimmock, MR; Pavlov, KM; Cholewa, M; Lewis, SJ; Tromba, G; Quiney, HM; Brennan, PCPurpose Propagation-based phase-contrast computed tomography (PB-CT) is a method for three-dimensional x-ray imaging that utilizes refraction, as well as absorption, of x rays in the tissues to increase the signal-to-noise ratio (SNR) in the resultant images, in comparison with equivalent conventional absorption-only x-ray tomography (CT). Importantly, the higher SNR is achieved without sacrificing spatial resolution or increasing the radiation dose delivered to the imaged tissues. The present work has been carried out in the context of the current development of a breast CT imaging facility at the Australian Synchrotron. Methods Seven unfixed complete mastectomy samples with and without breast cancer lesions have been imaged using absorption-only CT and PB-CT techniques under controlled experimental conditions. The radiation doses delivered to the mastectomy samples during the scans were comparable to those approved for mammographic screening. Physical characteristics of the reconstructed images, such as spatial resolution and SNR, have been measured and compared with the results of the radiological quality assessment of the complete absorption CT and PB-CT image stacks. Results Despite the presence of some image artefacts, the PB-CT images have outperformed comparable absorption CT images collected at the same radiation dose, in terms of both the measured objective image characteristics and the radiological image scores. The outcomes of these experiments are shown to be consistent with predictions of the theory of PB-CT imaging and previous reported experimental studies of this imaging modality. Conclusions The results presented in this paper demonstrate that PB-CT holds a high potential for improving on the quality and diagnostic value of images obtained using existing medical x-ray technologies, such as mammography and digital breast tomosynthesis (DBT). If implemented at suitable synchrotron imaging facilities, PB-CT can be used to complement existing imaging modalities, leading to more accurate breast cancer diagnosis. © 2023 American Association of Physicists in Medicine
- ItemX-ray phase-contrast computed tomography for full breast mastectomy imaging at the Australian Synchrotron(Society of Photo-Optical Instrumentation Engineers (SPIE), 2021-08-01) Arhatari, BD; Nesterets, YI; Taba, ST; Maksimenko, A; Hall, CJ; Stevenson, AW; Häsermann, D; Lewis, SJ; Dimmock, M; Thompson, D; Mayo, SC; Quiney, HM; Gureyev, TE; Brennan, PCOne of the imaging modalities offered by the Imaging and Medical Beamline (IMBL) at the Australian Synchrotron is Xray phase-contrast propagation-based computed tomography (PB-CT). The unique combination of high coherence and high brightness of radiation produced by synchrotron X-ray sources enables phase contrast imaging with excellent sensitivity to small density differences in soft tissues and tumors. The PB-CT images using spatially coherent radiation show high signal-to-noise ratio (SNR) without reducing the spatial resolution. This is due to the combined effect of forward free-space propagation and the advanced step of phase retrieval in the reconstruction processes that allows to accommodate noisier recorded images. This gives an advantage of potentially reducing the radiation dose delivered to the sample whilst preserving the reconstructed image quality. It is expected that the PB-CT technique will be well suited for diagnostic breast imaging in the near future with the advantage that it could provide better tumor detection and characterization/grading than mammography and other breast imaging modalities/techniques in general. The PB-CT technique is expected to reduce false negative and false positive cancer diagnoses that result from overlapping regions of tissue in 2D mammography and avoid patient pain and discomfort that results from breast compression. The present paper demonstrates that PB-CT produces superior results for imaging low-density materials such as breast mastectomy samples, when compared to the conventional absorption-based CT collected at the same radiation dose. The performance was quantified in terms of both the measured objective image characteristics and the subjective scores from radiological assessments. This work is part of the ongoing research project aimed at the introduction of 3D X-ray medical imaging at the IMBL as innovative tomographic methods to improve the detection and diagnosis of breast cancer. Major progress of this project includes the characterization of a large number of mastectomy samples, both normal and cancerous. © (2021) Society of Photo-Optical Instrumentation Engineers (SPIE).
- ItemX-ray phase-contrast computed tomography for soft tissue Imaging at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron(MDPI, 2021-04-30) Arhatari, BD; Stevenson, AW; Abbey, B; Nesterets, YI; Maksimenko, A; Hall, CJ; Thompson, D; Mayo, SC; Fiala, T; Quiney, HM; Taba, ST; Lewis, SJ; Brennan, PC; Dimmock, MR; Häusermann, D; Gureyev, TEThe Imaging and Medical Beamline (IMBL) is a superconducting multipole wiggler-based beamline at the 3 GeV Australian Synchrotron operated by the Australian Nuclear Science and Technology Organisation (ANSTO). The beamline delivers hard X-rays in the 25–120 keV energy range and offers the potential for a range of biomedical X-ray applications, including radiotherapy and medical imaging experiments. One of the imaging modalities available at IMBL is propagation-based X-ray phase-contrast computed tomography (PCT). PCT produces superior results when imaging low-density materials such as soft tissue (e.g., breast mastectomies) and has the potential to be developed into a valuable medical imaging tool. We anticipate that PCT will be utilized for medical breast imaging in the near future with the advantage that it could provide better contrast than conventional X-ray absorption imaging. The unique properties of synchrotron X-ray sources such as high coherence, energy tunability, and high brightness are particularly well-suited for generating PCT data using very short exposure times on the order of less than 1 min. The coherence of synchrotron radiation allows for phase-contrast imaging with superior sensitivity to small differences in soft-tissue density. Here we also compare the results of PCT using two different detectors, as these unique source characteristics need to be complemented with a highly efficient detector. Moreover, the application of phase retrieval for PCT image reconstruction enables the use of noisier images, potentially significantly reducing the total dose received by patients during acquisition. This work is part of ongoing research into innovative tomographic methods aimed at the introduction of 3D X-ray medical imaging at the IMBL to improve the detection and diagnosis of breast cancer. Major progress in this area at the IMBL includes the characterization of a large number of mastectomy samples, both normal and cancerous, which have been scanned at clinically acceptable radiation dose levels and evaluated by expert radiologists with respect to both image quality and cancer diagnosis. © 2021 The Authors, Licensee MDPI, Basel, Switzerland. Open Access Creative Commons Attribution (CC BY).