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Browsing by Author "Häusermann, D"

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Comparison 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, PC
Propagation-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).
Effect 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, ST
Purpose: 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).
Energy 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, CJ; Dimmock, M; Lockie, D; Rickard, M; Giannoitti, N; Peele, AG; Quiney, HM; Gureyev, TE; Brennan, PC; Taba, ST
Purpose: 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).
First experiments on the Australian Synchrotron imaging and medical beamline, including investigations of the effective source size in respect of x-ray imaging
(International Union of Crystallography, 2010-01) Stevenson, AW; Mayo, SC; Häusermann, D; Maksimenko, A; Garrett, RF; Hall, CJ; Wilkins, SW; Lewis, RA; Myers, DE
The Imaging and Medical beamline at the Australian Synchrotron achieved 'first light' in December 2008. Here, the first experiments performed on the beamline are reported, which involved both X-ray imaging and tomography studies for a range of samples. The use of a plastic-edge phantom for quantitative measurements of contrast and resolution proved to be very instructive and helped to confirm certain parameter values such as the effective horizontal source size, detector resolution and average X-ray energy for the polychromatic beam. © 2010, International Union of Crystallography
Gd-TPP-DOTA reduces cell viability in cancer cells via synchrotron radiotherapy
(Australian National University, 2021-08-24) Middleton, RJ; Howell, NR; Livio, E; Wyatt, NA; Chacon, A; Fraser, BH; Barnes, M; Cameron, M; Rendina, LM; Häusermann, D; Lerch, MLF; Safavi-Naeini, M
High-Z elements have been proposed as radiosensitisers in X-ray photon radiotherapy due to their emission of multiple high-LET photo- and Auger electrons following X-ray irradiation. Gadolinium is a particularly attractive candidate radiosensitiser, since it can also be used as an MRI contrast agent. In this study, we report on the efficacy of Gd-triphenylphosphonium salt-DOTA (Gd(III)-TPP-DOTA) for synchrotron microbeam radiation therapy dose enhancement. The compound utilises the mitochondrial targeting moiety triphenylphosphonium (TPP) to accumulate Gd in the inner mitochondrial membrane. Experiments were conducted using the dynamic mode option at hutch 2B of the Imaging and Medical Beamline at the Australian Synchrotron. Human glioblastoma multiforme cells (T98G cell line) were cultured to 80-90% confluence in T12.5 flasks. Approximately 24 hours prior to irradiation, the cultures were either treated with a 500 μM solution of Gd(III)DOTA-TPP or a vehicle control. Spatial dose distribution of synchrotron broad beam (BB) and single/multiple microbeams were measured using a micron-scale X-Tream dosimetry system and Gafchromic films in air and at 2 cm depth in solid water (same depth as the monolayer of cells in T12.5 flasks). A total of 96 flasks were irradiated, with doses of 0, 1, 2, 3, 4, 5, 10 and 16 Gy delivered in valley (MRT) or uniformly (BB). Post irradiation, each flask was re-seeded into 7 x 96 well-plates to perform the resazurin cell proliferation assay up to 7 days after irradiation. Our preliminary analysis indicates that for cells irradiated by 3 Gy of BB or MRT radiation, the addition of Gd(III)DOTA-TPP results in a reduction in viable cell mass by 24.25% and 25.79%, respectively, compared with untreated flasks. © The Authors
High resolution dynamic imaging at the Australian Synchrotron
(Australian Institute of Physics, 2013-02-06) Häusermann, D
Not available
The imaging and medical beamline is expanding
(Australian Nuclear Science and Technology Organisation, 2021-11-24) Häusermann, D; McKinlay, J; Morey, C; Pelliccia, D
Synchrotron radiation has many advantages, but it is also flawed. And its biggest flaw happens to be its fundamental intrinsic property! The radiation is emitted in the plane of the stored beam and we are stuck with the infamous ‘letterbox door’ beam profile. At least when not tinkering with focused undulator beams. In clinical imaging research, this beam shape is a serious disadvantage. In fact, when compared with the field of view of commercial medical imaging devices, it is often the showstopper when engaging with a clinician to discuss medical application of the IMBL. So how will we image human patients in 2022, as part of our world leading research project in breast CT imaging and cancer detection? Our vertical ‘letter box opening’ at 135 meter is 3 cm, at 35 keV, with a roll off of 50%. This is far from ideal for imaging the breasts of a patient lying in a prone position on our robotic positioning and scanning stage. Consequently, we have designed and tested a Bragg-Bragg beam expander to be placed downstream of our double-bent-Laue primary monochromator. The net result is an 8 cm vertical beam profile at 135 meter, with minimal roll off, to match the vertical field of view of our new EIGER2 CdTe X 3M clinical detector. This paper will present the design of our beam expander and the results of our in-air tests. This device will be installed in vacuum in the next machine shutdown. © 2021 The Authors
Imaging 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, TE
Breast 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
Imaging breast microcalcifications using dark-field signal in propagation-based phase-contrast tomography
(Australian Nuclear Science and Technology Organisation, 2021-11-24) Aminzadeh, A; Arhatari, BD; Maksimenko, A; Hall, CJ; Häusermann, D; Peele, AG; Fox, J; Kumar, B; Prodanovic, Z; Dimmock, MR; Lockie, D; Pavlov, KM; Thompson, D; Mayo, SC; Paganin, DM; Tavakoli, A; Lewis, SJ; Brennan, PC; Quiney, HM; Gureyev, TE
Breast microcalcifications are an important primary radiological indicator of breast cancer. However, microcalcification classification and diagnosis can 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 tomography (PB-CT) of breast tissues. Five fresh mastectomies containing microcalcifications were scanned at the Imaging and Medical beamline of the Australian Synchrotron at different X-ray energies and radiation doses. Both bright-field and dark-field images were extracted from the same data sets using different image processing methods [1]. A quantitative analysis was performed in terms of visibility and contrast-to-noise ratio of microcalcifications. The results show that the visibility of the microcalcifications in the dark-field images is more than two times higher compared to the bright-field images. Dark-field images have also provided more accurate information about the size and shape of the microcalcifications [2]. Therefore, dark-field PB-CT images are likely to help radiologists evaluate the probability of breast cancer more effectively. This work has been conducted in the course of developing a medical imaging facility at the Australian Synchrotron for advanced breast cancer imaging. © The Authors
Incorporating clinical imaging into the delivery of microbeam radiation therapy
(MDPI, 2021-09-30) Paino, JR; Barnes, M; Engels, E; Davis, JA; Guatelli, S; de Veer, M; Hall, CJ; Häusermann, D; Tehei, M; Corde, S; Rosenfeld, AB; Lerch, MLF
Synchrotron microbeam radiation therapy is a promising pre-clinical radiation treatment modality; however, it comes with many technical challenges. This study describes the image guidance protocol used for Australia’s first long-term pre-clinical MRT treatment of rats bearing 9L gliosarcoma tumours. The protocol utilises existing infrastructure available at the Australian Synchrotron and the adjoining Monash Biomedical Imaging facility. The protocol is designed and optimised to treat small animals utilising high-resolution clinical CT for patient specific tumour identification, coupled with conventional radiography, using the recently developed SyncMRT program for image guidance. Dosimetry performed in small animal phantoms shows patient dose is comparable to standard clinical doses, with a CT associated dose of less than 1.39cGy and a planar radiograh dose of less than 0.03cGy. Experimental validation of alignment accuracy with radiographic film demonstrates end to end accuracy of less than ±0.34mm in anatomical phantoms. Histological analysis of tumour-bearing rats treated with microbeam radiation therapy verifies that tumours are targeted well within applied treatment margins. To date, this technique has been used to treat 35 tumour-bearing rats. © 2021 by the Authors. Licensee MDPI, Basel, Switzerland.
Jaws caught on the IMBL
(Australian Nuclear Science and Technology Organisation, 2021-11-25) Maksimenko, A; Reser, D; Häusermann, D; De Veer, M; Panagiotopoulou, O; Huveneers, C; Wright, D; Hall, CJ
Maturational changes in feeding behaviour among sharks are associated with increased mineralisation of the teeth and jaws, but this relationship has only been demonstrated in a few species. Large, highly mobile shark species are rarely available for detailed anatomical study, despite their importance for ecological health and widespread interest among the general population. We examined the crania, jaws, and teeth of two great white sharks (Carcharodon carcharias), a 2.3 m juvenile and a 3.2 m young adult. The CT scans used a 230 keV (mean energy) polychromatic beam from the 4 Tesla wiggler, with a filtration of 6mmAl, 6mmCu, 3mmMo and 3mmPb. The detector was a Teledyne-Dalsa Xineos 3030HR with 100µm pixels, a width of 300mm, and a 1mm CsI converter for high efficiency at high energy. Image noise was reduced by collecting 18,000 projections per rotation to deliver an image quality good enough to segment out different tissue types. With a beam size of 300mm x 35mm, the shark head was covered by ‘tiling’, and stitching the tiles, with the full-head image made up of two columns and 21 tiles, to image a 600mm x 520mm area. Total scan time was 9 hours. The heads were also imaged using conventional CT and 7 Tesla MRI for finite element modelling of bite forces produced by the jaw musculature. These results will be compared with measurements of the difference in mineralisation of tooth and jaw cartilage between the two specimens to assess developmental changes in tooth and jaw hardness as the animals shift their diets from largely fish-based (juvenile) to larger prey, such as seals, scavenged whales and surfers (adults). © The Authors
Microtomography applications at the Imaging and Medical Beamline of the Australioan Synchrotron (sic)
(Australian Microscopy and Microanalysis Society, 2016-02-04) Maksimenko, A; Acres, RG; Hall, CJ; Häusermann, D; Stevenson, AW; Livingston, J; Pearson, J
The Imaging and Medical Beamline (IMBL) of the Australian Synchrotron (AS) is now becoming one of the most advanced instruments of this type in the world. It is designed to provide a wide variety of imaging techniques including but not limited to the in-line and analyzed phase contrasts, monochromatic and pink beam imaging. Three beamline’s enclosures at various distances, when combined with the 25kW superconducting multipole wiggler and double Laue bent monochromator provide the end user a good choice of beam characteristics ranging from the hi-flux for high resolution and size up to huge 48x5cm beam at 134m from the source with the allowed energy range 17-120kEv. The wide range of the area detectors allows the computed tomography (CT) and tomosynthesis methods to be applied to almost any known X-ray imaging modality. The beamline’s data acquisition system is directly linked to the high performance computing facilities tuned for the on-the-fly real-time reconstruction and 3D rendering. Deep integration of the acquisition, reconstruction and rendering facilities allows one to think of the their combination as of a single system with modular architecture. The system is designed for the fully automated experiments with minimal user interaction. This report summarizes implemented, designed and planned features of the beamline as applied to the microtomography experiments. Some latest outcomes of the CT system are presented with the samples coming of different fields of science: Biology, Geology, Paleontology, Medicine and others.
A novel anthropomorphic phantom composed of tissue-equivalent materials for use in experimental radiotherapy: design, dosimetry and biological pilot study
(MDPI, 2023-04-26) Breslin, T; Paino, JR; Wegner, M; Engels, E; Fiedler, S; Forrester, HB; Rennau, H; Bustillo, J; Cameron, M; Häusermann, D; Hall, CJ; Krause, D; Hildebrandt, G; Lerch, MLF; Schültke, E
The production of anthropomorphic phantoms generated from tissue-equivalent materials is challenging but offers an excellent copy of the typical environment encountered in typical patients. High-quality dosimetry measurements and the correlation of the measured dose with the biological effects elicited by it are a prerequisite in preparation of clinical trials with novel radiotherapy approaches. We designed and produced a partial upper arm phantom from tissue-equivalent materials for use in experimental high-dose-rate radiotherapy. The phantom was compared to original patient data using density values and Hounsfield units obtained from CT scans. Dose simulations were conducted for broad-beam irradiation and microbeam radiotherapy (MRT) and compared to values measured in a synchrotron radiation experiment. Finally, we validated the phantom in a pilot experiment with human primary melanoma cells. © 2023 The Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) licence.
Propagation-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, PC
Rationale 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.
Propagation-based phase-contrast imaging of the breast: image quality and the effect of x-ray energy and radiation dose
(Oxford University Press, 2023-10-01) Gunaseelan, I; Zadeh, AA; Arhatari, BD; Maksimenko, A; Hall, CJ; Häusermann, D; Kumar, B; Fox, J; Quiney, HM; Lockie, D; Lewis, SF; Brennan, PJ; Gureyev, TE; Taba, ST
Objectives: Propagation-based phase-contrast computed tomography (PB-CT) is a new imaging technique that exploits refractive and absorption properties of X-rays to enhance soft tissue contrast and improve image quality. This study compares image quality of PB-CT and absorption-based CT (AB-CT) for breast imaging while exploring X-ray energy and radiation dose. Methods: Thirty-nine mastectomy samples were scanned at energy levels of 28-34keV using a flat panel detector at radiation dose levels of 4mGy and 2mGy. Image quality was assessed using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), spatial resolution (res) and visibility (vis). Statistical analysis was performed to compare PB-CT images against their corresponding AB-CT images scanned at 32keV and 4mGy. Results: The PB-CT images at 4mGy, across nearly all energy levels, demonstrated superior image quality than AB-CT images at the same dose. At some energy levels, the 2mGy PB-CT images also showed better image quality in terms of CNR/Res and vis compared to the 4mGy AB-CT images. At both investigated doses, SNR and SNR/res were found to have a statistically significant difference across all energy levels. The difference in vis was statistically significant at some energy levels. Conclusion: This study demonstrates superior image quality of PB-CT over AB-CT, with X-ray energy playing a crucial role in determining image quality parameters. Advances in knowledge: Our findings reveal that standard dose PB-CT outperforms standard dose AB-CT across all image quality metrics. Additionally, we demonstrate that low dose PB-CT can produce superior images compared to standard dose AB-CT in terms of CNR/Res and vis. © The British Institute of Radiology This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 Unported License http://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted non-commercial reuse, provided the original author and source are credited.
Propagation-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, PC
Purpose 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
The spinal cord as organ of risk: assessment for acute and subacute neurological adverse effects after microbeam radiotherapy in a rodent model
(MDPI, 2023-04-26) Jaekel, F; Paino, JR; Engels, E; Klein, M; Barnes, M; Häusermann, D; Hall, CJ; Zheng, G; Wang, HX; Hildebrandt, G; Lerch, MLF; Schültke, E
Microbeam radiotherapy (MRT), a high dose rate radiotherapy technique using spatial dose fractionation at the micrometre range, has shown a high therapeutic efficacy in vivo in different tumour entities, including lung cancer. We have conducted a toxicity study for the spinal cord as organ of risk during irradiation of a target in the thoracic cavity. In young adult rats, the lower thoracic spinal cord was irradiated over a length of 2 cm with an array of quasi-parallel microbeams of 50 µm width, spaced at a centre-to-centre distance of 400 µm, with MRT peak doses up to 800 Gy. No acute or subacute adverse effects were observed within the first week after irradiation up to MRT peak doses of 400 Gy. No significant differences were seen between irradiated animals and non-irradiated controls in motor function and sensitivity, open field test and somatosensory evoked potentials (SSEP). After irradiation with MRT peak doses of 450–800 Gy, dose-dependent neurologic signs occurred. Provided that long-term studies do not reveal significant morbidity due to late toxicity, an MRT dose of 400 Gy can be considered safe for the spinal cord in the tested beam geometry and field size. © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.
Synchrotron CT of an equine digit at the Australian Synchrotron imaging and medical beamline
(International Union of Crystallography, 2021-11) Montgomery, JB; Klein, M; Boire, JR; Beck, C; Häusermann, D; Maksimenko, A; Hall, CJ
Laminitis is an extremely painful and debilitating condition of horses that can affect their athletic ability and even quality of life. The current gold standard for assessment of laminar tissue is histology, which is the only modality that enables detailed visualization of the lamina. Histology requires dissection of the hoof and therefore can only represent one specific time point. The superior spatial and contrast resolution of synchrotron computed tomography (sCT), when compared with readily available imaging modalities, such as radiographs and conventional CT, provides an opportunity for detailed studies of the lamina without the need for hoof dissection and histological assessment. If the resolution of histology can be matched or even approached, dynamic events, such as laminar blood flow, could also be studied on the microscopic tissue level. To investigate this possible application of sCT further, two objectives are presented: (i) to develop a protocol for sCT of an equine digit using cadaver limbs and (ii) to apply the imaging protocol established during (i) for sCT imaging of the vasculature within the foot using an ex vivo perfusion system to deliver the vascular contrast. The hypotheses were that sCT would allow sufficient resolution for detailed visualization to the level of the secondary lamellae and associated capillaries within the equine digit. Synchrotron CT enabled good visualization of the primary lamellae (average length 3.6 mm) and the ex vivo perfusion system was able to deliver vascular contrast agent to the vessels of the lamina. The individual secondary lamellae (average length 0.142 mm) could not be seen in detail, although differentiation between primary and secondary lamellae was achieved. This approaches, but does not yet reach, the current gold standard, histology, for assessment of the lamellae; however, with further refinement of this imaging technique, improved resolution may be accomplished in future studies. © 2021 The Authors - Open Access CC BY.
X-ray microbeam measurements with a high resolution scintillator fibre-optic dosimeter
(Springer Nature, 2017-09-29) Archer, J; Li, E; Petasecca, M; Dipuglia, A; Cameron, M; Stevenson, AW; Hall, CJ; Häusermann, D; Rosenfeld, AB; Lerch, MLF
Synchrotron microbeam radiation therapy is a novel external beam therapy under investigation, that uses highly brilliant synchrotron x-rays in microbeams 50 μm width, with separation of 400 μm, as implemented here. Due to the fine spatial fractionation dosimetry of these beams is a challenging and complicated problem. In this proof-of-concept work, we present a fibre optic dosimeter that uses plastic scintillator as the radiation conversion material. We claim an ideal one-dimensional resolution of 50 μm. Using plastic scintillator and fibre optic makes this dosimeter water-equivalent, a very desirable dosimetric property. The dosimeter was tested at the Australian Synchrotron, on the Imaging and Medical Beam-Line. The individual microbeams were able to be resolved and the peak-to-valley dose ratio and the full width at half maximum of the microbeams was measured. These results are compared to a semiconductor strip detector of the same spatial resolution. A percent depth dose was measured and compared to data acquired by an ionisation chamber. The results presented demonstrate significant steps towards the development of an optical dosimeter with the potential to be applied in quality assurance of microbeam radiation therapy, which is vital if clinical trials are to be performed on human patients. © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
X-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, TE
The 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).

Browsing by Author "Häusermann, D"

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