1,720,969 research outputs found
Multimodal spectral histopathology for quantitative diagnosis of residual tumour during basal cell carcinoma surgery
Get PDFBasal cell carcinoma (BCC) is the most common type of cancer in the world. The preferred method of treating BCC is surgical excision followed by histopathological investigation of the removed tissue. Mohs micrographic surgery is a highly specialised surgical procedure which involves the removal of sequential layers of skin until a tumour is completely excised. Each removed skin layer is analysed through frozen section histopathology to assess whether residual BCC is present on the resection margin and if so, a subsequent tissue layer is removed. Mohs surgery is only used to treat BCCs in high risk locations (such as the head and neck area) or recurrences. Mohs surgery is not available universally, as it requires highly specialised personnel, is labour intensive and expensive. New imaging modalities are therefore being developed to investigate whether they can accompany or replace frozen section histopathology in assessing the surgical margin of removed skin specimens within the Mohs clinical workflow.
This thesis describes the development and optimisation of a prototype instrument that utilises a multimodal spectral histopathology (MSH) approach to investigate the surgical margins of excised skin tissue samples. Multimodal spectral histopathology combines autofluorescence confocal microscopy and Raman spectroscopy to objectively determine whether the margins of an investigated sample are BCC-positive.
The prototype instrument was developed to measure tissue samples automatically (without requiring user input), and to display the measurement results as easy-to-interpret tissue maps. The maps do not require specialist interpretation, meaning that MSH can be used by non- spectroscopy users, resulting in improved objectivity of diagnosis. The MSH measurement and data analysis software, which enables the automated operation of the instrument, was optimised by measuring 97 frozen skin samples obtained after Mohs surgery of 70 patients. The MSH software was shown to be transferable between similar instruments, demonstrating the potential to produce such devices at scale.
The performance of the prototype instrument for frozen skin samples was tested by measuring an independent set of 10 samples from 9 patients. The prototype was shown to correctly diagnose all samples based on their corresponding adjacent histopathology sections.
The prototype instrument was then moved into the Mohs clinic where it was used to measure fresh tissue samples intra-operatively. In order to adapt the prototype instrument to the clinical setting, 50 fresh tissue samples from 18 patients were investigated. The MSH software and tissue handling procedure were adapted to account for the abundant presence of blood and surgical positioning ink. The measurement time was also shortened to 30 minutes per Mohs layer, to increase compatibility with the Mohs workflow. The performance of the prototype instrument for fresh samples was assessed by measuring an independent set of 30 samples from 12 patients, after the software changes were finalised. Fresh sample diagnoses were shown to be in accordance with Mohs frozen sections for 96.4% of the test samples. These results were enabled by the use of a multinomial logistic regression classification model capable of distinguishing between BCC and healthy spectra with a 94.3% sensitivity and a 95.3% specificity.
The prototype described in this thesis is, therefore, the first fully-automated instrument based on Raman spectroscopy for intra-operative microscopic imaging of surgical margins during cancer surgery, suitable to be used by a non-specialist user in a clinical environment
Multimodal spectral histopathology for quantitative diagnosis of residual tumour during basal cell carcinoma surgery
Get PDFBasal cell carcinoma (BCC) is the most common type of cancer in the world. The preferred method of treating BCC is surgical excision followed by histopathological investigation of the removed tissue. Mohs micrographic surgery is a highly specialised surgical procedure which involves the removal of sequential layers of skin until a tumour is completely excised. Each removed skin layer is analysed through frozen section histopathology to assess whether residual BCC is present on the resection margin and if so, a subsequent tissue layer is removed. Mohs surgery is only used to treat BCCs in high risk locations (such as the head and neck area) or recurrences. Mohs surgery is not available universally, as it requires highly specialised personnel, is labour intensive and expensive. New imaging modalities are therefore being developed to investigate whether they can accompany or replace frozen section histopathology in assessing the surgical margin of removed skin specimens within the Mohs clinical workflow.
This thesis describes the development and optimisation of a prototype instrument that utilises a multimodal spectral histopathology (MSH) approach to investigate the surgical margins of excised skin tissue samples. Multimodal spectral histopathology combines autofluorescence confocal microscopy and Raman spectroscopy to objectively determine whether the margins of an investigated sample are BCC-positive.
The prototype instrument was developed to measure tissue samples automatically (without requiring user input), and to display the measurement results as easy-to-interpret tissue maps. The maps do not require specialist interpretation, meaning that MSH can be used by non- spectroscopy users, resulting in improved objectivity of diagnosis. The MSH measurement and data analysis software, which enables the automated operation of the instrument, was optimised by measuring 97 frozen skin samples obtained after Mohs surgery of 70 patients. The MSH software was shown to be transferable between similar instruments, demonstrating the potential to produce such devices at scale.
The performance of the prototype instrument for frozen skin samples was tested by measuring an independent set of 10 samples from 9 patients. The prototype was shown to correctly diagnose all samples based on their corresponding adjacent histopathology sections.
The prototype instrument was then moved into the Mohs clinic where it was used to measure fresh tissue samples intra-operatively. In order to adapt the prototype instrument to the clinical setting, 50 fresh tissue samples from 18 patients were investigated. The MSH software and tissue handling procedure were adapted to account for the abundant presence of blood and surgical positioning ink. The measurement time was also shortened to 30 minutes per Mohs layer, to increase compatibility with the Mohs workflow. The performance of the prototype instrument for fresh samples was assessed by measuring an independent set of 30 samples from 12 patients, after the software changes were finalised. Fresh sample diagnoses were shown to be in accordance with Mohs frozen sections for 96.4% of the test samples. These results were enabled by the use of a multinomial logistic regression classification model capable of distinguishing between BCC and healthy spectra with a 94.3% sensitivity and a 95.3% specificity.
The prototype described in this thesis is, therefore, the first fully-automated instrument based on Raman spectroscopy for intra-operative microscopic imaging of surgical margins during cancer surgery, suitable to be used by a non-specialist user in a clinical environment
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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