ORCID Profile
0000-0001-6443-0147
Current Organisations
SA Health
,
University of South Australia
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Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.EJVS.2019.01.031
Abstract: The aim was to determine whether lead containing and lead free composite garments in current use provide the level of radiation protection stated by manufacturers. Fifteen garments, produced by five different manufacturers using eight different composites, were randomly selected for testing from four hospitals in South Australia. Labelling, material composition, design, and condition of the garments were assessed by direct garment examination, garment label, and product information. Garment attenuation was tested in a simulated angiography suite using a Siemens Ysio Max digital Xray machine. The front and back panels of each garment were tested under direct beam at 100 kVp. A Perspex phantom was used to simulate the density and scatter properties of the human abdomen. The front panels of each garment were tested under scattered radiation at Xray tube voltages of 50 and 70 kVp. Forty-seven per cent of front panels and 90% of back panels provided lower lead equivalence than claimed by the manufacturer. Twenty per cent of front panels and 62% of back panels tested did not meet the minimum International Electrotechnical Commission requirements for angiographic use. There was a 38 fold difference in front panel performance of garments to scatter radiation, which were all labelled 0.5 mm lead equivalence. 56% of garments had differences in scatter transmission of at least 49% when tested at 50 and 70 kVp. The results show that lead containing and lead free composite garments probably provide less radiation protection than manufacturer stated lead equivalence. The demonstrated wide variations in attenuation of scatter radiation are greater than previously reported. It was found that most garments failed to comply with labelling standards. The study highlights challenges in radiation shielding and the need to identify composites that consistently provide better attenuation per unit weight than lead.
Publisher: Springer Science and Business Media LLC
Date: 22-07-2019
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.EJMP.2019.06.012
Abstract: This paper aims to review the dosimetry and utility of currently implemented imaging modalities for assessment of multiple myeloma and consider the role of tin filtration computed tomography (CT) as a potential replacement to current standard practice. Radiation output of tin CT was measured experimentally and used for software-based dose calculation. Resultant effective dose was then compared to calculated planar radiography doses and published doses of other imaging modalities. Based on ex le patient parameters used for modalities and 14 projection planar radiography site protocols, doses are comparable between planar radiography and tin filtration CT (approximately 0.9 and 1.0 mSv respectively). Both studies carried a reduced radiation burden compared to Expected Pathologically Increased Contrast-CT (EPIC-CT), FDG-PET and MIBI SPECT/CT (5.7, 11.1-20.0 and 13.0 mSv respectively). Tin filtered CT provided visualisation of multiple myeloma at doses comparable to planar radiography and where available may be a suitable alternative, following due consideration of patient specific justification and optimisation in line with best practice.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.JACR.2019.05.045
Abstract: Head and neck carcinomas are clinically challenging malignancies because of tumor heterogeneities and resilient tumor subvolumes that require in idualized treatment planning and delivery for an improved outcome. Although current approaches to diagnosis and therapy have boosted locoregional control, the long-term survival in this patient group remains unchanged over the last decades. A new approach to head and neck cancer management is therefore needed to better identify patient subgroups that are responsive to specific therapies. The aim of this article is to review the current status of knowledge and practice utilizing big data toward personalized therapy in head and neck cancers based on CT and PET imaging modalities. Literature published in English since 2000 was searched using Medline. Additional articles were retrieved via pearling of identified literature. Publications were reviewed and summarized in tabulated format. Studies based on big data in head and neck cancer are limited however, the field of radiomics is under continuous development and provides valuable input for personalized treatment. Using PET/PET CT biomarkers for patient treatment in idualization and response prediction seems promising, especially in regard to detection of hypoxia and clonogenic cancer stem cells. Literature shows that macroscopic changes in medical images (whether structural or functional) are correlated with biologic and biochemical changes within a tumor. Current trends in data science suggest that the ideal model for decision support in head and neck cancers should be based on human-machine collaboration, namely, on (1) software-based algorithms, (2) physician innovation collaboratives, and (3) clinician mix optimization.
Publisher: MDPI AG
Date: 19-03-2021
DOI: 10.3390/DIAGNOSTICS11030551
Abstract: Research into machine learning (ML) for clinical vascular analysis, such as those useful for stroke and coronary artery disease, varies greatly between imaging modalities and vascular regions. Limited accessibility to large erse patient imaging datasets, as well as a lack of transparency in specific methods, are obstacles to further development. This paper reviews the current status of quantitative vascular ML, identifying advantages and disadvantages common to all imaging modalities. Literature from the past 8 years was systematically collected from MEDLINE® and Scopus database searches in January 2021. Papers satisfying all search criteria, including a minimum of 50 patients, were further analysed and extracted of relevant data, for a total of 47 publications. Current ML image segmentation, disease risk prediction, and pathology quantitation methods have shown sensitivities and specificities over 70%, compared to expert manual analysis or invasive quantitation. Despite this, inconsistencies in methodology and the reporting of results have prevented inter-model comparison, impeding the identification of approaches with the greatest potential. The clinical potential of this technology has been well demonstrated in Computed Tomography of coronary artery disease, but remains practically limited in other modalities and body regions, particularly due to a lack of routine invasive reference measurements and patient datasets.
No related grants have been discovered for Chris Boyd.