Dissertations / Theses on the topic 'Scan head'

Thesis (MMED. (Forensic Medicine)) --University of Limpopo, 2019
Traumatic intracranial haemorrhages are common, carry a high mortality rate and are therefore commonly known in the practice of forensic pathology as unnatural deaths. Studies have demonstrated a significant decrease in mortality rate among patients who received surgical interventions compared to patients who were treated medically. Missed or mis-diagnoses, which may be apparent during an autopsy procedure, present possible missed treatment opportunities. Aim/objective and methods The study investigated the discrepancy rate and discrepancy pattern of diagnosis between antemortem brain computed tomography (CT) scan findings and autopsy findings in deceased patients with traumatic intracranial haemorrhage (TIH). A quantitative retrospective descriptive study was conducted based on bodies presented with TIH at Pietersburg Hospital Forensic Pathology Department. A total of consecutive 85 cases with antemortem CT (ACT) scan findings were compared to autopsy findings using percentage agreement and Cohen’s kappa statistics. Results and conclusion There was a fair overall agreement (k=0.38) with overall discrepancy rate of 24.74%, ranging from 9.41% to 34.12% for individual TIH between ACT scan and autopsy findings. Subarachnoid haemorrhage had the lowest agreement between the ACT scan and autopsy findings for TIH. Patient and doctor factors associated with the discrepancies were assessed. Those associated factors, if addressed, may have a positive impact on patient outcome. As far as the debate on non-invasive autopsy procedure is concerned, as a result of existing discrepancy rate, we conclude that ACT should not be used alone in the determination of cause of death but may be used in conjunction with autopsy findings.

The aim of this thesis is automatic alignment of head CT scan. Currently, the alignment is performed manually by an expert, however this process is time consuming. Therefore, methods for automatization of this process are being developed. Two algorithms for alignment in axial and coronal plane were designed based on bilateral symmetry of head. Following an algorithm for alignment in sagittal plane which uses CG-TOB reference line for rotation angle detection. Algorithms were implemented in MATLAB and tested and validated using a database of manually annotated head CT scans.

The diploma thesis addressed the issue of laser surface hardening using dynamic oscillation of the laser beam. The theoretical part presents the hardening technology and suitable using of laser equipments. The fiber laser YLS 2000 was used in the experiment and the hardened material was steel 12 050, which is suitable for laser hardening. The influence of two selected parameters of the scan head on the resulting structure and hardness of hardening layers was examined. Based on the results, the choice of optimal parameters for identical conditions with the experiment was recommended.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 45-46).
We investigate automating the task of segmenting structures in head and neck CT scans, to minimize time spent on manual contouring of structures of interest. We focus on the brainstem and left and right parotids. To generate contours for an unlabeled image, we employ an atlas of labeled training images. We register each of these images to the unlabeled target image, transform their structures, and then use a weighted voting method for label fusion. Our registration method starts with multi-resolution translational alignment, then applies a relatively higher resolution affine alignment. We then employ a diffeomorphic demons registration to deform each atlas to the space of the target image. Our weighted voting method considers one structure at a time to determine for each voxel whether or not it belongs to the structure. The weight for a voxel's vote from each atlas depends on the intensity difference of the target and the transformed gray scale atlas image at that voxel, in addition to the distance of that voxel from the boundary of the structure. We evaluate the method on a dataset of sixteen labeled images, generating automatic segmentations for each using the other fifteen images as the atlas. We evaluated the weighted voting method and a majority voting method by comparing the resulting segmentations to the manual segmentations using a volume overlap metric and the distances between contours. Both methods produce accurate segmentations, our method producing contours with boundaries usually only a few millimeters away from the manual contour. This could save physicians considerable time, because they only have to make small modifications to the outline instead of contouring the entire structure.
by Amelia M. Arbisser.
M.Eng.

Fusarium Head Blight (FHB) is a destructive disease caused by Fusarium graminearum that affects wheat (Triticum aestivum L.) worldwide. Breeding for resistance to FHB is arguably the best way to combat this disease. However, FHB resistance is highly complex and phenotypic screening is difficult. Molecular markers are a promising tool but breeding programs face the challenge of allocating resources in such a way that the optimum balance between phenotypic and genotypic selection is reached. An F2:3 population derived from a resistant x susceptible cross was subjected to phenotypic and genotypic selection. For phenotyping, a novel air separation method was used to measure percentage of damaged kernels (FDK). Heritability estimates were remarkably high, which was attributed to the type of cross and the quality of phenotyping. Genotypic selection was done by selecting resistance alleles at quantitative trait loci (QTL) on the 3BS (Fhb1) and the 2DL chromosomes. Fhb1 conferred a moderate but stable FHB resistance while the 2DL QTL conferred a surprisingly high level of resistance but with significant interaction with the environment. Phenotypic selection conferred higher or lower genetic gains than genotypic selection, depending on the selection intensity. Based on these results, different selection strategies are discussed.

Stroke is one of the major causes of death and disability worldwide. Fast diagnosis is of critical importance for stroke treatment. In clinical routine, a non-contrast CT (NCCT) is typically acquired immediately to determine whether the stroke is ischemic or hemorrhagic and plan therapy accordingly. In case of ischemia, early signs of infarction may appear due to increased water uptake. These signs may be subtle, especially if observed only shortly after symptom onset, but hold the potential to provide a crucial first assessment of the location and extent of the infarction. In this paper, we train a deep neural network to predict the infarct core from NCCT in an image-to-image fashion. To facilitate exploitation of anatomic correspondences, learning is carried out in the standardized coordinate system of a brain atlas to which all images are deformably registered. Apart from binary infarct core masks, perfusion maps such as cerebral blood volume and flow are employed as additional training targets to enrich the physiologic information available to the model. The method is evaluated using cross validation on the training data set consisting of 141 cases. For validation, we measure the overlap with the ground truth masks, the localisation performance and the agreement with both manual and automatic assessment of affected ASPECTS regions. It is shown that the additional targets improve the results signficantly, achieving an area-under-curve of 0.835 when compared with the automated assessment in ASPECTS region classification and providing a distance of 0 mm between the prediction maximum and the indicated stroke infarct core in the majority of severe strokes with an infarct core volume greater than 70 ml.
Stroke är en av de viktigaste orsakerna till dödsfall och funktionshinder över hela världen. Snabb diagnos är av avgörande betydelse för strokebehandling. I klinisk rutin utförs en datortomografi utan kontrastmedel omedelbart för att bestämma om en stroke är ischemisk eller hemorragisk och terapi planeras baserat på resultatet. I händelse av en ischemisk stroke kan tidiga tecken på infarkt uppstå på grund av ökat vattenupptag. Dessa tecken kan vara subtila, särskilt om de bara observeras strax efter symptomen börjat, men har potential att ge en avgörande första bedömning av infarktens plats och omfattning. I detta projekt tränar vi ett djupt neuralt nätverk för att förutsäga infarktkärnan från datortomografibilder på ett bild-till-bild-sätt. För att underlätta utnyttjandet av anatomiska korrespondenser genomförs lärandet i det standardiserade koordinatsystemet i en hjärnatlas i vilken alla bilder är deformerbart registrerade. Förutom binära infarktkärnmasker, används  erfusionskartor såsom cerebral blodvolym och flöde som ytterligare träningsmål. Därmed finns mer fysiologisk information som det neurala nätverket kan tränas på. Metoden utvärderas med hjälp av korsvalidering på träningsdatauppsättningen bestående av 141 patienter. För validering mäter vi överlappningen med de observerade maskerna, lokaliseringens kvalitet och utvärdering med både manuell och automatisk bedömning av berörda ASPECTS-regioner. Det visas att de ytterligare målen förbättrar resultaten betydande och uppnår en area-under-kurva på 0,835 jämfört med automatisk bedömning av klassifikationen av ASPECTS-regioner och ger ett avstånd av 0 mm mellan förutsägelsen maximalt och strokeinfarktkärnan i majoriteten av allvarliga fall av stroke med en infarktkärnvolym större än 70 ml.

Head motion is a significant source of image quality degradation in neurological PET scans. It is especially detrimental in PET scanners with high resolution, specifically the HRRT (High Resolution Research Tomograph) with a spatial resolution of approximately 2.5 mm. Head restraints are often used to minimize subject movement and subject comfort is essential to obtain reliable data. We have investigated subject movement during long scans (over an hour) and subject repositioning accuracy for a series of scans. The Polaris Vicra is a commercially available optical measurement device we used to measure the position and orientation of the subject's head over the course of the scan. A tracking tool was attached to a swim cap worn by the subject and tracked relative to a second tool attached to the scanner gantry. The head is a body part that can be treated as a rigid body. For rigid bodies, movement detected at the surface can be directly translated to any point in that body. We have used this principle and the Polaris Vicra's movement data to track several ROIs in subject's brains. We found that over the course of a long scan, ROIs placed near the occipital pole can move as much as 14 mm. This will cause significant blurring in images taken with the HRRT. The repositioning device tested was very accurate and repositioned the subject within 2 mm of her initial position.
Les mouvements de la tête sont une source significative de dégradation de la qualité de l'image provenant de PET scans. Ils jouent un rôle particulièrement négatif avec les scanners PET à haute définition comme le HHRT (High Resolution Research Tomograph) qui possède une résolution approximative de 2,5 mm. Différents outils de stabilisation de la tête sont souvent utilisés afin de minimiser les mouvements, et le confort du sujet est essentiel pour obtenir des résultats fiables. Nous avons testé les mouvements du sujet au cours de longs scans (plus d'une heure) ainsi que la précision du repositionnement du sujet lors d'une série de scans. Le Polaris Vicra est un instrument de mesure optique disponible sur le marché que nous avons utilisé pour mesurer la position et l'orientation de la tête du sujet durant le scan. Un outil mesurant les mouvements de la tête relativement au scanner a été attaché à un bonnet de bain déposé sur la tête du sujet. La tête peut être considérée comme un corps rigide. Pour les corps rigides, un mouvement détecté à la surface est directement relié au mouvement de n'importe quel point sur ce corps. Nous avons utilié ce principe ainsi que les données de mouvement du Polaris Vicra afin de dépister plusieurs régions d'intérêts dans le cerveau du sujet. Nous démontrons que durant un long scan, les régions d'intérêts situés près du pôle occipital peuvent se déplacer sur près de 12 mm. Ceci peut donc rendre l'image floue. L'outil de repositionnement testé s'est avéré très précis et a repositionné le sujet en deçà de 2 mm de sa position initiale.

Fusarium head blight (FHB) or head scab, caused by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)], is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Numerous strategies for scab resistance breeding are in use, including phenotypic selection for low severity and marker-assisted selection for resistance QTL. The most destructive consequences of scab are evidenced through a reduction in grain quality, and the presence of mycotoxins, the most common of which is deoxynivalenol (DON). Thus, there is great interest among breeders in selecting for resistance to both of these traits. To this end, a study was devised as follows. In 2010, 20 bulk F3 SRW wheat populations with scab resistant parents in their pedigrees were harvested by population from unreplicated plots near Lexington, KY. The plots were affected by a naturally occurring mild-moderate scab epidemic. The grain was sorted on a USDA/ARS and National Manufacturing Seed Sorter System with color camera according to a calibration that reflected visual differences between asymptomatic grain and grain showing FHB symptoms. This process was repeated in 2011 using grain from plots that had conidial suspension applied at anthesis. In 2012, an unreplicated plot study of the C0, C1 and C2 cycles of selection, inoculated with grain spawn and conidial suspension, was evaluated for Fusarium damaged kernels (FDK) and DON concentration. An additional cycle of selection was conducted by running the bulk grain through the sorter. In October 2012, 4 selection cycles of the 20 populations were planted in a RCB experiment at Lexington and Princeton, KY. Bulk populations were planted in both scab nursery and plots, and C3 accepted and rejected of all populations and derived lines of 2 populations were planted in the scab nursery in Lexington, KY. Some populations had FDK and DON reduction with selection, and some derived lines had either numerical or significant reduction with selection. Although the accepted fraction had non-significant reduction compared with the rejected fraction over the populations, FDK and DON means were obviously lower in accepted than in rejected fractions.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.
Background: Head computed tomography (CT) imaging is the gold standard study for rapidly identifying emergent traumatic brain injuries (TBIs). Exposure to the ionizing radiation utilized in CT increases lifetime risk for developing neoplasms. Currently there is little consensus on appropriate use of CT imaging for children with mild head injury. Clinical decision rules (CDRs) have been developed to identify children at very low risk of clinically significant brain injury. While these CDRs have been validated, their implementation has not been as well studied. Objective: To evaluate the efficacy of two CDRs in decreasing CT scan rate without missing clinically significant brain injuries. The two CDRs used in this study were the Children's Head Injury Algorithm for the Prediction of Important Clinical Events (CHALICE) and the Pediatric Emergency Care Applied Research Network (PECARN) algorithm. Both variations of the PECARN criteria for age 2 years and older and age <2 years were studied. Design/Methods: The medical records for patients with the diagnosis of head injury evaluated at the Maricopa Medical Center Pediatric Emergency Department for all of 2011 and 2012 were reviewed. A total of 331 charts were identified. The PECARN and CHALICE inclusion criteria and algorithms were applied to these charts to determine if the patients met criteria for CT scan. Patients with suspected non‐accidental injuries were excluded. Results: Of 331 patients, 238 met the inclusion criteria for CHALICE. 96 (40.3%) had CT scans performed. According to the algorithm, only 52 (21.8%) met criteria, which is an absolute rate reduction of 18.5%. One TBI was missed. 129 patients met the inclusion criteria for PECARN age 2 years and older. 73 (56.6%) had CT scans performed. 61 (47.2%) met criteria resulting in an absolute rate reduction of 9.4%. No TBIs were missed. 74 patients met inclusion criteria for PECARN age <2 years. Of these, 25 (33.7%) had CT scans performed and the same number met criteria resulting in no change in number of scans. One TBI was missed. Conclusions: Both the CHALICE and PECARN CDRs have the potential to reduce scan rates in our home institution. The CHALICE CDR would have resulted in a greater reduction in CT scans. PECARN also would have reduced the number of scans in children 2 years and older, but not in children <2 years old. The TBI that did not meet CDR criteria was also missed by clinical suspicion and a CT scan done on a later encounter was suspicious for a non‐accidental injury.

Automatic exposure control (AEC) is effective at reducing potentially harmful radiation doses without sacrificing image quality for many types of computed tomography (CT) scans. However, there is a need for more information regarding the use of AEC for CT head scans. This study was conducted at Johnson County Community Hospital in Mountain City, TN. Preexisting adult CT head scans (n)60 were randomly selected to form 2 stratified samples, (n)30 each. One sample used a standard protocol, and the other used a protocol with a mA-modulated AEC system, Siemens CARE Dose 4D. Causal-comparative analyses were conducted, and it was determined that AEC was effective at maintaining subjective image quality while reducing radiation doses an average of 38% for adult CT head scans. It was concluded that using AEC was an effective tool to optimize radiation doses for adult CT head scans in one particular setting, but more research on this topic is needed.

Fusarium head blight (FHB) is one of the most economically important diseases of small grains and continues to impact crops when environmental conditions are favorable to Gibberella zeae (Fusarium graminearum), the causal agent of the disease. Corn residues are considered to be primary sources of inoculum for epidemics of FHB. Therefore, knowledge of the movement of Gibberella zeae from a local source of infested corn residue is critical to the management of FHB in wheat and barley. Previous research made significant progress in defining the spatial dissemination of inoculum sources of G. zeae within agricultural fields, but was unable to clearly distinguish between within-field and background sources. Using amplified fragment length polymorphism, released clones of G. zeae were tracked within wheat and barley fields. This strategy allowed the distinction between the contributions of released clones to FHB, compared to that of background inocula. Corn residue infested with clones of G. zeae was placed into small replicated plots in winter wheat fields in New York and Virginia in 2007 and 2008 and wheat spikes were collected at 0, 3, 6, and â ¥24 m from the inoculum sources. Recovery of released clones decreased an average of 90% between 3 and 6 m from inoculum sources. Various amounts of corn residue infested with a single clone of G. zeae were placed into small replicated plots in winter wheat and barley fields in Virginia from 2008 to 2010. The use of minimal or conventional tillage and a moderately resistant cultivar of wheat or barley may reduce the contribution of within-field inocula to FHB; however, environmental conditions play an important role in the effectiveness of these management strategies. With the increase of corn production due to incentives for ethanol-based fuel, overwintering sites for G. zeae on corn residue are likely to increase. Our work contributes to an increased understanding of the influence of overwintered corn residue to FHB which will also direct future research on how to reduce the inoculum potential from within-field sources.
Ph. D.

The purpose with this project was to create a virtual reality game were the users should be able to carry out a thinning. The main goals are to use real forests terrains as terrain models in the game, the GameObjects and the teleportation system in the application should be able to handle changing terrains and the application should not cause virtual reality sickness. The application has been developed with the help of the game engine Unity and plugins from Unitys own asset store. User tests and measurements will be carried out in order to evaluate if the game causes virtual reality sickness or not. The results shows that it is possible to use real forests terrains and that the solution is suited for this application. The downside is that in order to use real life terrains several steps has to be taken and that the terrain object has to be designed manually. It also shows that the GameObjects and the Teleportation system has been implemented in a way so they can handle changing terrains. Furthermore it shows that some of the functionalities of the application could be improved, especially the scoring system. The users tests and the measurements showed that the application isn't causing virtual reality sickness but it also showed that the users feels like there are things missing in the application

The Heat Shock Protein 90 (Hsp90) is an essential and highly conserved chaperone that facilitates the maturation of a wide array of client proteins, including many kinases. These clients in turn regulate a wide array of cellular processes, such as signal transduction, and transcriptional reprogramming. As a result, the activity of Hsp90 has the potential to influence physiology, which in turn may influence the ability to adapt to new environments. Previous studies using a deep mutational scanning approach, (EMPIRIC) identified multiple substitutions within a 9 amino acid substrate-binding loop of yeast Hsp90 that provides a growth advantage for yeast under elevated salinity conditions and costs of adaptation under alternate environments. These results demonstrate that genetic alterations to a small region of Hsp90 can contribute to evolutionary change and promote adaptation to specific environments. However, because Hsp90 is a large, highly dynamic and multi-functional protein the adaptive potential and evolutionary constraints of Hsp90 across diverse environments requires further investigation. In this dissertation I used a modified version of EMPIRIC to examine the impact of environmental stress on the adaptive potential, costs and evolutionary constraints for a 118 amino acid functional region of the middle domain of yeast Hsp90 under endogenous expression levels and the entire Hsp90 protein sequence under low expression levels. Endogenous Hsp90 expression levels were used to observe how environment may affect Hsp90 mutant fitness effects in nature, while low expression levels were used as a sensitive readout of Hsp90 function and fitness. In general, I found that mutations within the middle domain of Hsp90 have similar fitness effects across many environments, whereas, under low Hsp90 expression I found that the fitness effects of Hsp90 mutants differed between environments. Under individual conditions multiple variants provided a growth advantage, however these variants exhibited growth defects in other environments, indicating costs of adaptation. When comparing experimental results to 261 extant eukaryotic sequences I find that natural variants of Hsp90 support growth in all environments. I identified protein regions that are enriched in beneficial, deleterious and costly mutations that coincides with residues involved in co-chaperone-client-binding interactions, stabilization of Hsp90 client-binding interfaces, stabilization of Hsp90 interdomains and ATPase chaperone activity. In summary, this thesis uncovers the adaptive potential, costs of adaptation and evolutionary constraints of Hsp90 mutations across several environments. These results complement and extend known structural and functional information, highlighting potential adaptive mechanisms. Furthermore, this work elucidates the impact environment can have on shaping Hsp90 evolution and suggests that fluctuating environments may have played a role in the long-term evolution of Hsp90.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
O cultivo do trigo no Brasil é marcado pelo elevado número de doenças capazes de causar danos à produção. Entre as principais doenças que afetam o trigo está a giberela ou fusariose da espiga, causada pelo agente etiológico Gibberella zeae (Schw.) Petch, (anamorfo Fusarium graminearum Schwabe) que causa impacto negativos não somente à produtividade mas também a qualidade dos grãos produzidos. As condições ambientais para que a infecção ocorra carac terizam-se com temperaturas de 20-25°C e duração do molhamento foliar de, no mínimo, 48 horas consecutivas. O controle químico é realizado via aplicação de fungicidas a partir do inicio da floração estendendo-se até o final do florescimento, sendo que este tipo de controle caracteriza-se pela sua menor eficiência quando comparado com o controle de doenças foliares. Caso as condições climáticas impeçam a realização das aplicações de fungicidas no período indicado, o controle fica muito dificultado, por outro lado, se não ocorrer clima favorável à infecção, não se justifica o tratamento. A ineficiência dos tratos culturais no controle de giberela, associado à natureza quantitativa da característica de resistência, e o fato de sofrer alta influência do ambiente resultam na necessidade de identificar fontes efetivas de resistência que possam ser utilizadas em programas de melhoramento de trigo. De fato, existem culturas onde o controle das doenças mais importantes ocorre, quase que exclusivamente, por meio da resistência sendo que a identificação de genotipos que contenham resistência é um dos primeiros passos para selicioná-los. Desta forma, é fundamental o conhecimento de cultivares que apresentem níveis de resistência a giberela e métodos que possam identificar estas cultivares. Frente ao exposto o objetivo deste trabalho foi: i) separar genótipos suscetíveis e que contenham diferentes níveis de resistência utilizando avaliações morfológicas e moleculares; ii) verificar a resistência à giberela nas cultivares Frontana e Pampeano. Para isso foram utilizadas avaliações de características morfológicas citadas na literatura e associadas a resistência à giberela, assim como, o meprego de primers descritos na literatura significativamente associados à QTL de resistência à giberela. Como resultado do estudo espera-se auxiliar no desenvolvimento de ferramentas que possam ser utilizadas em programas de melhoramento de trigo visando facilitar a identificação de fontes de resistência.
The cultivation of wheat in Brazil is marked by the large number of diseases that can damage the production. Among the major diseases affecting wheat is wheat scab or Fusarium head blight (FHB), caused by the agent Gibberella zeae (Schw.) Petch (anamorph Fusarium graminearum Schwabe ) that causes negative impact not only on productivity but also the quality of the grain produced. The environmental conditions for infection are temperatures between 20-25°C and 48 consecutive hours of leaf wetness. Chemical control is performed via application of fungicides from the start extending until the end of flowering, and this type of control is characterized by its low efficiency when compared to the disease control. If the weather conditions prevent the aplication of fungicide applications within this period, there is no possibility control, on the other hand, if it does not favorable environment for infec tion treatment is not justified. The inefficiency of cultural control of FHB, associated with the quantitative trait (QTL- Quantitative traits loci)of resistance, and the fact of suffering high influence of the environment results in the need to identify effective sources of resistance that can be used in wheat breeding programs. In fact, there are cultures where control of major diseases occurs almost exclusively through resistance where the identification of genotypes containing resist ance is one of the first steps in their selection. Thus it is crucial to understand cultivar present levels of resistance to FHB and methods that can identify these cultivars.The objective of this study was: i) separate susceptible and containing different levels of resistance using molecular and morphological evaluations; ii) determine FHB resistance using cultivars Frontana and Pampeano as a source of resistance. Using morphological assessments cited in the literature and associated with resistance to FHB, as, primers as described in the literature as significantly associated with QTL for resistance to FHB. As a result of the study one expects to develop tools that can be used to facilitate the identification of sources of resistance.

Die Narbenbildung des Hautorgans stellt für die gegenwärtige Medizin weiterhin eine schwierige Aufgabe dar. Die frühzeitige Beeinflussung des Wundheilungspro- zesses hin zu einer verminderten oder narbenlosen Heilung scheint von entschei- dender Bedeutung. Ein vielversprechender Ansatz ist die präoperative Laserthe- rapie und dadurch erzeugte Hitzeschockantwort. Auf molekulare Ebene kommt es u.a. zur Expression von Hitzeschockproteine. Die vorliegende in-vitro Studie beschäftigte sich mit der laserinduzierten Hochregulation des Hitzeschockproteins 70 in den epidermalen Schichten. Hierfür wurden drei nicht ablative Lasersysteme mit insgesamt 12 verschiedenen Parametereinstellungen verwendet (1.540-nm Er:Glass- , 755-nm Alexandrit-, 1.064-nm Nd:YAG-Laser). Mithilfe eines humanen Hautexplantatmodells sollte unter gleichbleibenden Bedingungen Zeitpunkt und Konzentration der maximal induzierten Hsp70-Expression sowie epidermale Schä- digungen dargestellt werden. In der verfügbaren Literatur waren hierzu nur begrenzt Daten vorhanden. Alle drei Lasersysteme zeigten signifikante Hsp70-Expressionen. Der Zeitpunkt der maximalen Hsp70-Expression konnte zwischen Tag 1 und 3 festgehalten werden. Dabei zeigten die Lasersysteme unterschiedliche Hsp70- Maxima und unterschiedliche Epidermisschädigungen. Die Ergebnisse ließen schlussfolgern, dass eine potenzielle präoperative Narbenprävention tendeziell ein Tag vor dem chirurgischen Eingriff und mit den stärkeren Parametereinstellungen des 1.064-nm Nd:YAG Lasers durchgeführt werden sollte.

Background: Computed tomography (CT) imaging is an indispensable tool in the management of acute paediatric illness. It offers quick answers, allowing timely lifesaving decision-making. Clinical evidence is required to maximise its benefits against radiation-exposure risks to patients and cost to the healthcare system. Aims: The study aimed to retrospectively investigate clinical presentation and indications of head CT at a tertiary paediatric hospital. Methods: Records of children presenting with acute illness to the medical emergency unit, excluding trauma, of Red Cross War Memorial Children’s Hospital, Cape Town, over one year (2013) were retrospectively reviewed. Participants were included if they underwent head CT scan within 24 hours of presentation. Clinical data were extracted from records and CT findings reported by a paediatric radiologist. Results: Inclusion criteria were met by 311 patients; 188 (60.5%) were boys. The median age was 39.2 (IQR 12.6-84.0) months. Commonest indications were seizures (n=169;54.3%), reduced level of consciousness (n=140;45.0%), headache (n=74;23.8%) and suspected ventriculoperitoneal shunt (VPS) malfunction (n=61;19.7%). In 217 (69.8%) patients CT showed no adverse findings. In the 94 (30.2%) patients in whom CT abnormalities were detected, the predominant findings were hydrocephalus (n=54;57.4%) and cerebral oedema (n=29;30.9%). Abnormal CT findings were commoner in patients with nausea or vomiting (n=21;9.3%, p=0.05) papilloedema (n=3;1.3%, p=0.015) and long tract signs (n=23;10.2%, p=0.02). Forty-seven patients (15.1%) required surgical intervention after CT of which 40 (85.1%) needed a ventricular drainage procedure. A larger proportion of patients with VPS (25/62;40.3%) required surgical intervention compared to patients without VPS (22/249;8.8%, p <0.001) Conclusion: Most children presenting with acute illness (excluding trauma) and undergoing emergency head CT have normal findings. Patients with ventriculoperitoneal shunts constituted a large proportion of patients requiring intervention after CT. Considerations should be made to use clinical presentation to select patients most likely to benefit from CT.

Les techniques de stockage de l’information ont connu un essor important avec l’avènement de l’informatique et de toutes les activités multimédia. L’enregistrement hélicoïdal sur bande, qui reste le média le plus économique est destiné à stocker de très importants volumes d’information. Le nombre de têtes d’écriture/lecture utilisées par ce type d’enregistreurs augmente pour améliorer les taux de transfert. Le problème du positionnement entre les têtes devient donc central. La technologie de fabrication des têtes pour l’enregistrement hélicoïdal proposé par la société Alditech qui est entièrement intégrée sur silicium constitue le point de départ du travail présenté ici. En effet, l’objectif est de réaliser une tête double en s’affranchissant des problèmes de positionnement des têtes entre elles grâce aux technologies importées de la microélectronique. La démarche qui a amené à proposer la structure du composant est présentée ici. La faisabilité de cette structure est ensuite validée par l’étude de briques de base technologiques et la réalisation d’un premier démonstrateur. Par ailleurs les perturbations du fonctionnement magnétique des têtes introduites par l’utilisation d’une technologie têtes doubles ainsi que les phénomènes de diaphonie entre les têtes sont étudiés par simulation numériques
The data storage techniques knew an important development due to the success of the multimedia activities. Helical recording on tape, that remains the most economical media, is used for the very important data volumes. The number of read/write heads used by this type of recorders increases to improve the transfer rates. Thus the problem of the relative heads positioning becomes central. The manufacture technology of helical recording heads proposed by Alditech is fully integrated on silicon wafers. It constitutes the departure point of the work presented here. The purpose is to build a double head suppressing the positioning problems of heads thanks to the imported technologies of the microelectronic. The gait that brought to propose the structure of the component is presented here. Next the feasibility of this structure is validated by the study of basic technological steps and the realization of the first demonstrator. Besides the perturbations of the magnetic function of the heads introduced by the “double head” technology as well as the crossfeed phenomena between the heads are studied by numerical simulations

Head-up display (HUD) är en beprövad teknik inom flyg och bil, vilken gör det möjligt för piloter och förare att få tillgång till information utan att uppmärksamheten avleds från omvärlden. Liknande fördelar kan uppnås genom installation av HUD i tåg. Syftet med denna studie är att utveckla ett användargränssnitt för HUD baserat på European Rail Traffic Management System (ERTMS). HUD kommer att vara en extra säkerhetsfunktion för tågen för att förhindra förare från att skifta fokus mellan instrumentpanelen och omgivningen, vilket leder till minskad förareutmattning och bättre observation av spåren framåt. Scenario Based Design-metoden har använts för att genomföra projektarbetet och i rapporten diskuteras metodens  fördelar och begränsningar. Användningen av scenarier har gjort det möjligt för designteamet att på djupet förstå de situationer som förarna står inför samt  har hjälpt till att under workshops få en bättre förståelse för drivrutinerna. Dessutom har rekommendationer för hårdvara, installation och framtida arbete beskrivits för fortsatt genomförande av projektet.
Head-up display (HUD) has a proven track record in the aviation and automobile sectors, allowing pilots and drivers to access information without diverting attention from the outside world. Similar benefits may be realized by the installation of HUD in locomotive cabs. The objective of this thesis work is to develop the user interface for HUD based on the ERTMS system. The HUD will be an added safety feature to the trains to prevent drivers from refocusing between the instrument panel and the outside view thus leading to reduced driver fatigue and better observation of the tracks ahead. Scenario Based Design method has been used to implement the project work with discussions regarding its advantages and limitations. The use of scenarios has allowed the design team to understand the scenarios that the drivers face in depth and has aided during the workshops to understand the drivers’ routine better. Additionally, recommendations for the hardware, installation and future work have been provided to support further implementation of the project.

Indiana University-Purdue University Indianapolis (IUPUI)
Radiation Therapy has been one of the most common techniques to treat various types of cancers, in particular is Head and Neck Cancer (HNC) which accounts for three percent of all cancers in the United States. During the treatment procedure, the patient is immobilized using immobilization devices such as the full head face mask, bite blocks, stereotactic frame, etc. to get accurate location of tumor. The disadvantage of these devices is that they are very uncomfortable to the patient especially people suffering from Post-Traumatic Stress Disorder (PTSD) and claustrophobia who cannot wear any confined masked system such as the full head mask or bite block during the treatment procedure. To mitigate this problem, there has been a lot of research in modifying such immobilizing devices without neglecting the accurate location of tumor. To this end, the research presented in this thesis focuses on developing a mask less system with accurately locating the position of tumor using the technique of coordinate transformation at the same time fulfilling the three important characteristics: • Comfort • Accuracy • Low price Such a system is comfortable to the patient because no confining mask system is used and we choose minimal contact points on the patient for fixing the patient. Traditionally, such type of cancer treatment is carried out in two stages: Diagnosis stage, which identifies the location of the tumor and the external markers and the Treatment stage where the tumor is treated with immobilization device being common in both the stages. In the new system, the immobilization devices vary at the two stages. The head position is monitored by using pressure sensor assembly where spring and pressure sensor setup detects the amount and direction of head deviation. We also prepare a customized 3D printed nose bridge part for extra referencing in the treatment room. Also, it is important that we use material for our immobilization devices which does not contain any metal and MRI compatible. Once the patient lies down on the treatment couch and is immobilized using the immobilization devices, then tumor location is calculated using the theory of coordinate transformation and transformation matrix in the Diagnosis and Treatment Stage. To validate the system, simulation of immobilization devices used in the new design was carried out using ANSYS Workbench 15.0 and LS-Dyna software’s Explicit Dynamics method. The simulation for the head-fixing device showed a deflection of ±0.1974 mm with respect to machine isocenter with a load of 60 N, which is lower than the customer requirement of ±3 mm with respect to machine isocenter of head deviation. The material used for the external markers for patient positioning was selected to be polyetheretherketone (PEEK) which is a radiolucent and widely used MRI compatible material. The system also takes into consideration the effect of weight loss, which is one of the drawbacks of the current systems. Although still in the development stage, this mask less system holds to be the next new variety of immobilization devices that are comfortable to the patient and less expensive to be implemented in future cancer treatment practices.

碩士
臺北醫學大學
傷害防治學研究所
95
About one million people in the US receive brain computed tomographic examination every year due to head injuries.with 80% of them suffering a mild head injury. Among patients arriving in the emergency room with a Glasgow Coma Scale (GCS) of 15, 3%-15% of them were found to be abnormal in their brain CT scan, and up to 5% of them required neurosurgical intervention. We used the Taiwan National Head Injury Database collected by the Head and Spinal Injury Research Team. we selected patients (n=2,294) with a mild head injury in from July 1,2005 to June 30,2006. Based on information from the database and clinical research material, we then established a neural network to predict whether any abnormality appeared in the brain CT in patients with a mild head injury. The ANN’S ability to discriminate outcomes was assessed using receiver operating characteristic (ROC) curve analysis and the results were compared with a multiple logistic regression model. The results of the study that brain CT abnormalities following a mild head injury occurred in 44.2% of the patients, and that 17 predictive variables were identified by the ANN model. When tested on the same validation set, the ANN model had the greatest area under the ROC curve (AUC=0.887). we also found that a pair-wise comparison between the ANN and LR (AUC=0.861) models showed a similar predictive performance (p=0.078). The ANN model had the best simultaneous sensitivity and specificity at two pre-defined cut-off values. If the cut-off point sensitivity was fixed at an optimal level of 90.3%,we found the study showed that the ANN model had a better specificity and performance than a classical statistical logistical regression model (87% vs. 50.3%) Based on this study results, we conclude that we can merge clinical tests to determinate the exceptional outliers from the CT results after studying mild head injury, symptoms, such as vomiting and headache, to help clinicians better decide on whether to order brain CT scan.

The present work deals with the development of a computational geometric framework for vision modeling for performing visibility and legibility analyses in Digital Human Modeling (DHM) using the field-of-view (FoV), estimated geometrically from 3D tessellated head scans. DHM is an inter-disciplinary area of research with the prime objective of evaluating a product, job or environment for intended users through computer-based simulations. Vision modeling in the existing DHM’s has been primarily addressed through FoV modeling using right circular cones (RCC). Perimetry literature establishes that the human FoV is asymmetric due to unrestricted zygomatic vision and restrictions on the nasal side of the face. This observation is neither captured by the simplistic RCC models in DHM, nor rigorously studied in vision literature. Thus, the RCC models for FoV are inadequate for rigorous simulations and the accurate modeling of FoV is required in DHM. The computational framework developed in this work considers three broad components namely, the geometric estimation and representation of FoV, visibility and statistical visibility, and legibility of objects in a given environment. A computational geometric method for estimating FoV from 3D laser-scanned models of the human head is presented in this work. The strong one-to-one similarity between computed and clinically perimetry maps establishes that the FoV can be geometrically computed using tessellated head models, without necessarily going through the conventional interaction based clinical procedures. The algorithm for FoV computation is extended to model the effect of gaze-direction on the FoV resulting in binocular FoV. A novel unit-cube scheme is presented for robust, efficient and accurate modeling of FoV. This scheme is subsequently used to determine the visibility of 3D tessellated objects for a given FoV. In order to carry out population based visibility studies, the statistical modeling FoV and generation of percentile-based FoV curves are introduced for a given population of FoV curves. The percentile data thus generated was not available in the current ergonomics or perimetry literature. Advanced vision analysis involving character-legibility is demonstrated using the unit-cube with an improved measure to incorporate the effect of character-thickness on its legibility.

碩士
國立成功大學
航空太空工程學系碩博士班
94
With the development of the laser technique, the industrial applications have increased more than before. Laser power, laser wavelength, cavity and scan head are the key points of the laser processing systems. The scan head is the equipment which affects the accuracy of the laser focus, because it can control the direction of the laser and adjust the laser focus. In this research, we discuss how to control the galvanometer of the scan head precisely as soon as possible. Galvanometer is one of the voice-coil motors. It has the low moment of inertia and high bandwidth. It’s a mechanical system with the settling time on the level of minimum second. To match up the characteristic of high bandwidth, the traditional technique uses the analog control. However, the noise affects the analog control very much and altering the control law is equivalent to redesigning the control circuit. Therefore, we try to use the digital control in this research. In this research, the gray box is used to establish the numerical model of the galvanometer and then use the frequency response to prove the model. After that, the two phase PID control is designed and the PC-Based system is used to operate. The experiment shows that the settling time of the 20° position control is 4.15ms. It already reaches the extremity of the performance of the PC-Based system. In order to reduce the settling time and increase the accuracy, we use the DSP system to be the core digital system. According to the experiment, we find that the settling time can reduce 11.84%.At least, according to the result of experiments, the three phase controller is used to improve the performance.

Title: Reliability of Child SCAT 3 Component Scores in Children at Rest and Following Exercise Author Names: Jeff Billeck, BPE, CAT(C)1, Mike Ellis, MD2, Jeff Leiter, PhD2, Joanne Parsons, PhD, BPT3. Jason Peeler, PhD, CAT(C)4 Problem: A lack of research exists regarding the test-retest reliability of the Child Sport Concussion Assessment Tool 3 (Child SCAT 3) in healthy non-concussed adolescent females in both baseline and post-exercise settings. Method: This study consisted of two testing sessions. Within each session the Child Sport Concussion Assessment Tool 3 (Child SCAT 3) was administered once prior to exercise and once after a bout of exercise. Results: Individual component scores displayed a wide range of reliability and response stability values. A positive correlation existed within one session, between child symptom scores and slower rates of heart rate recovery after exercise. Conclusions: Overall, the Child SCAT 3 appears to be a moderately reliable assessment tool when used to evaluate uninjured female children. However, further research is required to clarify the exact sources of method error within individual Child SCAT 3 component scores.
May 2016

While it is well known that exposure to radiation can result in cataract formation, questions still remain about the presence of a dose threshold in radiation cataractogenesis. Since the exposure history from diagnostic CT exams is well documented in a patient’s medical record, the population of patients chronically exposed to radiation from head CT exams may be an interesting area to explore for further research in this area. However, there are some challenges in estimating lens dose from head CT exams. An accurate lens dosimetry model would have to account for differences in imaging protocols, differences in head size, and the use of any dose reduction methods.

The overall objective of this dissertation was to develop a comprehensive method to estimate radiation dose to the lens of the eye for patients receiving CT scans of the head. This research is comprised of a physics component, in which a lens dosimetry model was derived for head CT, and a clinical component, which involved the application of that dosimetry model to patient data.

The physics component includes experiments related to the physical measurement of the radiation dose to the lens by various types of dosimeters placed within anthropomorphic phantoms. These dosimeters include high-sensitivity MOSFETs, TLDs, and radiochromic film. The six anthropomorphic phantoms used in these experiments range in age from newborn to adult.

First, the lens dose from five clinically relevant head CT protocols was measured in the anthropomorphic phantoms with MOSFET dosimeters on two state-of-the-art CT scanners. The volume CT dose index (CTDIvol), which is a standard CT output index, was compared to the measured lens doses. Phantom age-specific CTDIvol-to-lens dose conversion factors were derived using linear regression analysis. Since head size can vary among individuals of the same age, a method was derived to estimate the CTDIvol-to-lens dose conversion factor using the effective head diameter. These conversion factors were derived for each scanner individually, but also were derived with the combined data from the two scanners as a means to investigate the feasibility of a scanner-independent method. Using the scanner-independent method to derive the CTDIvol-to-lens dose conversion factor from the effective head diameter, most of the fitted lens dose values fell within 10-15% of the measured values from the phantom study, suggesting that this is a fairly accurate method of estimating lens dose from the CTDIvol with knowledge of the patient’s head size.

Second, the dose reduction potential of organ-based tube current modulation (OB-TCM) and its effect on the CTDIvol-to-lens dose estimation method was investigated. The lens dose was measured with MOSFET dosimeters placed within the same six anthropomorphic phantoms. The phantoms were scanned with the five clinical head CT protocols with OB-TCM enabled on the one scanner model at our institution equipped with this software. The average decrease in lens dose with OB-TCM ranged from 13.5 to 26.0%. Using the size-specific method to derive the CTDIvol-to-lens dose conversion factor from the effective head diameter for protocols with OB-TCM, the majority of the fitted lens dose values fell within 15-18% of the measured values from the phantom study.

Third, the effect of gantry angulation on lens dose was investigated by measuring the lens dose with TLDs placed within the six anthropomorphic phantoms. The 2-dimensional spatial distribution of dose within the areas of the phantoms containing the orbit was measured with radiochromic film. A method was derived to determine the CTDIvol-to-lens dose conversion factor based upon distance from the primary beam scan range to the lens. The average dose to the lens region decreased substantially for almost all the phantoms (ranging from 67 to 92%) when the orbit was exposed to scattered radiation compared to the primary beam. The effectiveness of this method to reduce lens dose is highly dependent upon the shape and size of the head, which influences whether or not the angled scan range coverage can include the entire brain volume and still avoid the orbit.

The clinical component of this dissertation involved performing retrospective patient studies in the pediatric and adult populations, and reconstructing the lens doses from head CT examinations with the methods derived in the physics component. The cumulative lens doses in the patients selected for the retrospective study ranged from 40 to 1020 mGy in the pediatric group, and 53 to 2900 mGy in the adult group.

This dissertation represents a comprehensive approach to lens of the eye dosimetry in CT imaging of the head. The collected data and derived formulas can be used in future studies on radiation-induced cataracts from repeated CT imaging of the head. Additionally, it can be used in the areas of personalized patient dose management, and protocol optimization and clinician training.

Dissertation