A presente dissertação aborda as relações entre a escrita chinesa e a instância da letra no inconsciente. O estudo aqui compartilhado se propôs a investigar que recursos a escrita chinesa pode oferecer ao psicanalista a fim de aguçar sua prática de leitura da "letra". Para tal, aprofundamos uma rede de conceitos imbricados que suportam essa questão: escrita, significante, letra, lalangue, semblante, poesia. A pesquisa realizada partiu da experiência de análise da pesquisadora, tocada pelos modos de intervenção em uma análise lacaniana. E se acentuou com a leitura d'O Seminário 24 (Lacan, 1976-7) onde consta a proposição lacaniana de que os analistas fossem à escrita poética dos chineses da dinastia Tang, indicando que neste sistema de escrita e no uso que os poetas fazem das letras chinesas haveria algo que pudesse interessar à psicanálise para sua práxis. A fim de cercar nosso objeto a escrita chinesa, vivenciamos a tentativa de aprendizado do mandarim, construímos uma interlocução direta com uma intercambista chinesa no Brasil, e estudamos a obra “L'écriture poétique chinoise”, de François Cheng, indicada por Lacan no “L’insu que sait de l’une-bévue s’aile à mourre” (1976). No que diz respeito ao laço desta pesquisa teórica com a clínica, trouxemos recortes de análises de sonhos e de falas no contexto de situação analítica. Tal percurso nos apontou que, ao escutar um sujeito em análise, além da escuta de seus significantes, deve-se estar atento à dimensão do que é letra, inclusive na sua dimensão visual, para então, quiçá, transpor algo disto para o simbólico. / The present dissertation deals with the relations between the chinese writting and the instance of the letter in the unconscious. The study shared here set out to investigate what resources the Chinese writing can offer to the analyst in order to increase his practice of reading of the “letter”. For this, we developed a network of interwoven concepts that support this issue: writing, signifier, letter, lalangue, semblant, poetry. The research started from the analysis experience of the researcher, influenced by the intervention modes in lacanian analysis and was accentuated reading the Seminar XXIV (Lacan, 1976-7), where is presented the lacanian proposition that the analyst should go to the Chinese poetic writing from the Tang Dynasty, indicating that in this writing system and on the use that the poets do of the Chinese writting would be found something that would interest to psychoanalysis for its praxis. In order to surround our object, we experience the attempt of Mandarin learning, as well as established a direct interaction with a Chinese exchange student in Brazil, and we studied the work “L'écriture poétique chinoise” (1977) of Francois Cheng, indicated by Lacan in “L’insu que sait de l’une-bévue s’aile à mourre” (1976). Concerning to the bond of this theoretical research with the clinic, we bring fragments of dream analysis, and speeches in the context of analytical situation. This way show to us that while listening to a subject in analysis, in addition to its significant listening we must be aware of the dimension of what is the letter, including its visual dimension, so than, perhaps, transpose something of it to the symbolic.

Ring artifacts are a common problem with the use of photon-counting detectors and commercial deployment rests on being able to compensate for them. Deep learning has been proposed as a candidate for tackling the inefficiency or high cost of traditional techniques. In that spirit, we propose a new approach to ring artifact reduction, namely one that employs Residual Networks in sinogram domain. We train them on data simulated via a realistic photon-counting CT model based on numerical phantoms of real scans acquired by the KiTS19 Challenge dataset. By exploring various architectures we find that shallow ResNets achieve a significant artifact reduction by staying more true to the ground truth in terms of not introducing new artifacts. All networks introduce a smoothing effect which is attributed to the use of MSE as a loss function. An alternative training scheme using patches instead of whole sinograms is tested and it shows a slightly improved model stability. Lastly, we demonstrate via a performance metric study that common metrics are not suitable for quantifying the performance in this problem, save for a potential new approach in the virtual mono-energetic domain. / Ringartefakter är ett vanligt problem vid användning av fotonräknande detektorer och kommersiell introduktion kräver att man kan kompensera för dem. Djupinlärning har föreslagits som en kandidat för att hantera ineffektiviteten eller de höga kostnaderna för traditionella tekniker. I den andan föreslår vi ett nytt tillvägagångssätt för att reducera ringartefakter, nämligen en som använder sig av residualnätverk i sinogramdomänen. Vi tränar dem på data simulerad via en realistisk fotonräkning CT modell baserad på numeriska fantomer av verkliga skanningar från datamängen KiTS19 Challenge. Genom att utforska olika arkitekturer finner vi att grunda ResNet uppnår en betydande minskning av artefakter genom bevara en större likhet med den sanna bilden när det gäller att inte introducera nya artefakter. Alla nätverk introducerar en utsmetningseffekt som tillskrivs användningen av MSE som en förlustfunktion. Ett alternativt träningsschema med utsnitt istället för hela sinogram testas och det visar en något förbättrad modellstabilitet. Slutligen visar vi genom en prestandamåttstudie att vanliga prestandamått inte är lämpliga för att kvantifiera prestandan i detta problem med undantag för ett potentiellt nytt tillvägagångssätt i den virtuella monoenergetiska domänen.

Interstitial and intracavitary brachytherapy plays an essential role in management of several malignancies. However, the achievable accuracy of brachytherapy treatment for prostate and cervical cancer is limited due to the lack of intraoperative planning and adaptive replanning. A major problem in implementing TRUS-based intraoperative planning is an inability of TRUS to accurately localize individual seed poses (positions and orientations) relative to the prostate volume during or after the implantation. For the locally advanced cervical cancer patient, manual drawing of the source positions on orthogonal films can not localize the full 3D intracavitary brachytherapy (ICB) applicator geometry. A new iterative forward projection matching (IFPM) algorithm can explicitly localize each individual seed/applicator by iteratively matching computed projections of the post-implant patient with the measured projections. This thesis describes adaptation and implementation of a novel IFPM algorithm that addresses hitherto unsolved problems in localization of brachytherapy seeds and applicators. The prototype implementation of 3-parameter point-seed IFPM algorithm was experimentally validated using a set of a few cone-beam CT (CBCT) projections of both the phantom and post-implant patient’s datasets. Geometric uncertainty due to gantry angle inaccuracy was incorporated. After this, IFPM algorithm was extended to 5-parameter elongated line-seed model which automatically reconstructs individual seed orientation as well as position. The accuracy of this algorithm was tested using both the synthetic-measured projections of clinically-realistic Model-6711 125I seed arrangements and measured projections of an in-house precision-machined prostate implant phantom that allows the orientations and locations of up to 100 seeds to be set to known values. The seed reconstruction error for simulation was less than 0.6 mm/3o. For the physical phantom experiments, IFPM absolute accuracy for position, polar angle, and azimuthal angel were (0.78 ± 0.57) mm, (5.8 ± 4.8)o, and (6.8 ± 4.0)o, respectively. It avoids the need to match corresponding seeds in each projection and accommodates incomplete data, overlapping seed clusters, and highly-migrated seeds. IFPM was further generalized from 5-parameter to 6-parameter model which was needed to reconstruct 3D pose of arbitrary-shape applicators. The voxelized 3D model of the applicator was obtained from external complex combinatorial geometric modeling. It is then integrated into the forward projection matching method for computing the 2D projections of the 3D ICB applicators, iteratively. The applicator reconstruction error for simulation was about 0.5 mm/2o. The residual 2D registration error (positional difference) between computed and actual measured applicator images was less than 1 mm for the intrauterine tandem and about 1.5 mm for the bilateral colpostats in each detector plane. By localizing the applicator’s internal structure and the sources, the effect of intra and inter-applicator attenuation can be included in the resultant dose distribution and CBCT metal streaking artifact mitigation. The localization accuracy of better than 1 mm and 6o has the potential to support more accurate Monte Carlo-based or 2D TG-43 dose calculations in clinical practice. It is hoped the clinical implementation of IFPM approach to localize elongated line-seed/applicator for intraoperative brachytherapy planning may have a positive impact on the treatment of prostate and cervical cancers.

La thèse a pour corpus le Canon des Poèmes (Shijing 詩經). S’appuyant sur l’étude de diverses interprétations des Poèmes, elle propose une application numérique pour interpréter le procédé incitatif (Xing 興) qui, jusque-là, n’a pas été clairement défini au plan rythmique. On y considère le sinogramme à la manière d’une note musicale, ou plus précisément d’une sino-syllabe (hanzi -yinjie 漢字-音節). La thèse peut alors se baser sur trois principes d’analyse :1. le contraste d’effectifs des sino-syllabes ;2. le calcul combinatoire des sino-syllabes ;3. l’échelle de perception des sino-syllabes.En suivant ces trois principes d’analyse, la thèse expose une méthode de lecture expérimentale qui distingue deux aspects dans les sino-syllabes aperçues pendant la lecture : les composants fondamentaux (qui créent le rythme dominant) et les idées principales (qui constituent le sujet thématique). La collaboration harmonieuse du rythme dominant avec le sujet thématique, révèle un système de figuration qui transforme les propos en langage poétique sur le plan rythmique. Ce système sert de référence interne au corpus pour objectiver le rapport rythmique entre le motif initial (= premier groupe de vers) et le motif final (= deuxième groupe de vers), dans la strophe créée par le procédé de Xing. On propose de nommer ce système « figure rythmique » (jielü xiuci 節律修辭). / The present thesis has chosen to center its attention on The Book of Odes. After the study of diverse interpretations of these poems, the thesis is brought to suggest using numeric humanities in the analysis of what Xing calls “the incentive process” whose rhythmic figure has not yet been clearly defined. At the condition that a sinogram could be considered a musical note, it would be more accurate to call it a “sino-syllable” (hanzi-yinjie 漢字-音節). The results are relayed by these three principles: 1. The contrast of occurrences between sino-syllables 2. The sino-syllables’ combinatorial calculation 3. The scale of perception in comprehending sino-syllablesApplying these principles of analysis, the thesis then reveals an experimental method of reading which sets forth two aspects: the basic components that create the dominant rhythm and the mean ideas that constitute the thematic subject.The harmonious relationship of the dominant rhythm with the thematic subject reveals a system that rhythmically transforms words to poetic language. This metaphorical system, called “rhythmic figure” (jiulü xiuci 節律修辭) for the purpose of this research, serves as an internal reference to the corpus to manifest the rhythmic relationship between the first and final patterns in verses produced with Xing’s method.

A produção lexicográfica japonesa iniciou-se logo no período Nara (710-794), florescendo durante o período Heian (794-1185). Os primeiros trabalhos constituíam-se de vocabulários e manuais de poesia, ou manuais de pronúncia para monges budistas. Alguns séculos depois, com a ascensão das classes militares, obras com o intuito de educar esses novos líderes começaram a organizar o léxico de maneira mais universal. Dentro dessa nova tradição, também é possível encontrar as obras produzidas pelos missionários portugueses da Companhia de Jesus. No presente trabalho serão exploradas as características de duas obras: o Vocabulario da Lingoa de Iapam com a declaração em Portugues, feito por alguns Padres, e Irmãos da Companhia de Iesu, e o RACVYOXV. Uma atenção especial será dada para o RACVYOXV, um dicionário de sinogramas dividido em três volumes impressos no ano de 1598, com uma máquina tipográfica trazida da Europa ao Japão pelos jesuítas. Existem poucos estudos dessas duas obras no ocidente, e, no caso do RACVYOXV, nenhum estudo em língua portuguesa. Através da comparação dos vocábulos e entradas desses dois trabalhos cuja publicação é separada por apenas cinco anos, o presente trabalho almeja apresentar o RACVYOXV com a descrição da sua estrutura interna e mostrar as possíveis relações entre o léxico deste com o do Vocabulario tendo em vista a finalidade pedagógica das duas obras / The Japanese lexicographic production begun at the Nara era (710-794), blooming during the Heian era (794-1185). The first works were vocabularies and poetry handbooks, or pronunciation guides to Buddhist monks. Few centuries later, with the rising of military classes, works with the intention to educate those new leaders started to organize all lexicon more universally. Inside this new tradition, it is also possible to find the works made by the Portuguese missionaries of the Companhia de Jesus. In this paper, it will be explored the features from two works: the Vocabulario da Lingoa de Iapam com a declaração em Portugues, feito por alguns Padres, e Irmãos da Companhia de Iesu, and the RACVYOXV. One special atention will be given to the RACVYOXV, one sinogram dictionary divided in three volumes, pressed at the year of 1598, with a typography machine brought from Europe to Japan by the Jesuits. There are few studies of these two works in the western world, and, about the RACVYOXV, there are no studies in Portuguese. Through the comparison of the lexicon and entries of those two works, whose publication are just five years apart, this paper wills to present the RACVYOXV with the description of its internal structure and show the possible relation with its lexicon with the Vocabularios lexicon, in the light of pedagogical finality of both works

A produção lexicográfica japonesa iniciou-se logo no período Nara (710-794), florescendo durante o período Heian (794-1185). Os primeiros trabalhos constituíam-se de vocabulários e manuais de poesia, ou manuais de pronúncia para monges budistas. Alguns séculos depois, com a ascensão das classes militares, obras com o intuito de educar esses novos líderes começaram a organizar o léxico de maneira mais universal. Dentro dessa nova tradição, também é possível encontrar as obras produzidas pelos missionários portugueses da Companhia de Jesus. No presente trabalho serão exploradas as características de duas obras: o Vocabulario da Lingoa de Iapam com a declaração em Portugues, feito por alguns Padres, e Irmãos da Companhia de Iesu, e o RACVYOXV. Uma atenção especial será dada para o RACVYOXV, um dicionário de sinogramas dividido em três volumes impressos no ano de 1598, com uma máquina tipográfica trazida da Europa ao Japão pelos jesuítas. Existem poucos estudos dessas duas obras no ocidente, e, no caso do RACVYOXV, nenhum estudo em língua portuguesa. Através da comparação dos vocábulos e entradas desses dois trabalhos cuja publicação é separada por apenas cinco anos, o presente trabalho almeja apresentar o RACVYOXV com a descrição da sua estrutura interna e mostrar as possíveis relações entre o léxico deste com o do Vocabulario tendo em vista a finalidade pedagógica das duas obras / The Japanese lexicographic production begun at the Nara era (710-794), blooming during the Heian era (794-1185). The first works were vocabularies and poetry handbooks, or pronunciation guides to Buddhist monks. Few centuries later, with the rising of military classes, works with the intention to educate those new leaders started to organize all lexicon more universally. Inside this new tradition, it is also possible to find the works made by the Portuguese missionaries of the Companhia de Jesus. In this paper, it will be explored the features from two works: the Vocabulario da Lingoa de Iapam com a declaração em Portugues, feito por alguns Padres, e Irmãos da Companhia de Iesu, and the RACVYOXV. One special atention will be given to the RACVYOXV, one sinogram dictionary divided in three volumes, pressed at the year of 1598, with a typography machine brought from Europe to Japan by the Jesuits. There are few studies of these two works in the western world, and, about the RACVYOXV, there are no studies in Portuguese. Through the comparison of the lexicon and entries of those two works, whose publication are just five years apart, this paper wills to present the RACVYOXV with the description of its internal structure and show the possible relation with its lexicon with the Vocabularios lexicon, in the light of pedagogical finality of both works

<p dir="ltr">X-ray computed tomography (CT) based on photon counting detectors (PCD) extends standard CT by counting detected photons in multiple energy bins. PCD data can be used to increase the contrast-to-noise ratio (CNR), increase spatial resolution, reduce radiation dose, reduce injected contrast dose, and compute a material decomposition using a specified set of basis materials [1]. Current commercial and prototype clinical photon counting CT systems utilize PCD-CT reconstruction methods that either reconstruct from each spectral bin separately, or first create an estimate of a material sinogram using a specified set of basis materials and then reconstruct from these material sinograms. However, existing methods are not able to utilize simultaneously and in a modular fashion both the measured spectral information and advanced prior models in order to produce a material decomposition. </p><p dir="ltr">We describe an efficient, modular framework for PCD-based CT reconstruction and material decomposition using Multi-Agent Consensus Equilibrium (MACE). Portions of this dissertation appear in [2]. Our method employs a detector proximal map or agent that uses PCD measurements to update an estimate of the path length sinogram. We also create a prior agent in the form of a sinogram denoiser that enforces both physical and empirical knowledge about the material-decomposed sinogram. The sinogram reconstruction is computed using the MACE algorithm, which finds an equilibrium solution between the two agents, and the final image is reconstructed from the estimated sinogram. Importantly, the modularity of our method allows the two agents to be designed, implemented, and optimized independently. Our results on simulated data show a substantial (2-3 times) noise reduction vs conventional maximum likelihood reconstruction when applied to a phantom used to evaluate low contrast detectability. Our results with measured data show an even higher reduction (2-12 times) in noise standard deviation. Lastly, we demonstrate our method on a Lungman phantom that more realistically represents the human body. </p>

Recent interests in computer based tools and simulations for PET imaging studies have been a leading source for many new developments. A strong emphasis in these studies has been to improve and optimize the PET scanners for better image quality and quantification of related system parameters. In this project, an attempt has been made to develop a Matlab tool intended to be of educational nature for new students where one can perform demonstration of PET-like imaging in a simple and quick way. This demonstration tool utilizes a high resolution, voxel based digital brain (Zubal) phantom as a primary study object. A tumor of specific size is defined by the user on a chosen slice of the phantom. The output images from this tool show the exact location of the predefined tumor. The algorithm attempts to estimate the positron emission direction, positron range distribution and photon detection in a circular geometry. Additional attempt has been made to estimate certain statistical parameters against a specific amount of radiotracer uptake. These include spatial resolution, photons count, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the ultimate PET image. Dependence of these estimated results by the tool on different system input parameters has been studied.

The focus of this thesis is variational image restoration techniques that involve novel non-smooth first-order gradient regularisers: Total Variation (TV) regularisation in image and data space for reconstruction of thin structures from PET data and regularisers given by an infimal-convolution of TV and $L^p$ seminorms for denoising images with piecewise affine structures. In the first part of this thesis, we present a novel variational model for PET reconstruction. During a PET scan, we encounter two different spaces: the sinogram space that consists of all the PET data collected from the detectors and the image space where the reconstruction of the unknown density is finally obtained. Unlike most of the state of the art reconstruction methods in which an appropriate regulariser is designed in the image space only, we introduce a new variational method incorporating regularisation in image and sinogram space. In particular, the corresponding minimisation problem is formed by a total variational regularisation on both the sinogram and the image and with a suitable weighted $L^2$ fidelity term, which serves as an approximation to the Poisson noise model for PET. We establish the well-posedness of this new model for functions of Bounded Variation (BV) and perform an error analysis through the notion of the Bregman distance. We examine analytically how TV regularisation on the sinogram affects the reconstructed image especially the boundaries of objects in the image. This analysis motivates the use of a combined regularisation principally for reconstructing images with thin structures. In the second part of this thesis we propose a first-order regulariser that is a combination of the total variation and $L^p$ seminorms with $1 < p \le \infty$. A well-posedness analysis is presented and a detailed study of the one dimensional model is performed by computing exact solutions for simple functions such as the step function and a piecewise affine function, for the regulariser with $p = 2$ and $p = 1$. We derive necessary and sufficient conditions for a pair in $BV \times L^p$ to be a solution for our proposed model and determine the structure of solutions dependent on the value of $p$. In the case $p = 2$, we show that the regulariser is equivalent to the Huber-type variant of total variation regularisation. Moreover, there is a certain class of one dimensional data functions for which the regularised solutions are equivalent to high-order regularisers such as the state of the art total generalised variation (TGV) model. The key assets of our regulariser are the elimination of the staircasing effect - a well-known disadvantage of total variation regularisation - the capability of obtaining piecewise affine structures for $p = 1$ and qualitatively comparable results to TGV. In addition, our first-order $TVL^p$ regulariser is capable of preserving spike-like structures that TGV is forced to smooth. The numerical solution of the proposed first-order model is in general computationally more efficient compared to high-order approaches.

No description available.