Non-rigid registration of serial intra-operative images for automatic brain shift estimation

Measurement of intra-operative brain motion is important to provide boundary conditions to physics-based deformation models that can be used to register pre- and intra-operative information. In this paper we present and test a technique that can be used to measure brain surface motion automatically. This method relies on a tracked laser range scanner (LRS) that can acquire simultaneously a picture and the 3D physical coordinates of objects within its field of view. This reduces the 3D tracking problem to a 2D non-rigid registration problem which we solve with a Mutual Information-based algorithm. Results obtained on images of a phantom and on images acquired intra-operatively that demonstrate the feasibility of the method are presented

Atlas-based segmentation of the brain for 3-dimensional treatment planning in children with infratentorial ependymoma

This paper presents a fully automated brain segmentation method that has been applied to a group of patients with infratentorial ependymoma. The purpose of the study was to test the hypothesis that fully-automated atlas-based segmentation methods provide useful normal tissue dosimetry from which dose-volume modeling may be performed in a manner equivalent to dose-volume data obtained from manual contouring. To test this hypothesis, we compared the integrated average dose for three small (chiasm, pituitary, hypothalamus) and three large (temporal lobes and total brain) normal tissue structures from ten patients using automated and manual contouring. There was no significant difference in the calculated average dose for the structures of interest. The greatest difference was noted for smaller structures which were located along the midline and in the gradient of dose. The results of this study form the basis of an ongoing larger study involving similar patients to evaluate automated and manual contouring as well as the clinical significance of any differences using dose-volume modeling

Automatic Segmentation of Brain Structures for Radiation Therapy Planning

Delineation of structures to irradiate (the tumors) as well as structures to be spared (e.g., optic nerve, brainstem, or eyes) is required for advanced radiotherapy techniques. Due to a lack of time and the number of patients to be treated these cannot always be segmented accurately which may lead to suboptimal plans. A possible solution is to develop methods to identify these structures automatically. This study tests the hypothesis that a fully automatic, atlas-based segmentation method can be used to segment most brain structures needed for radiotherapy plans even tough tumors may deform normal anatomy substantially. This is accomplished by registering an atlas with a subject volume using a combination of rigid and non-rigid registration algorithms. Segmented structures in the atlas volume are then mapped to the corresponding structures in the subject volume using the computed transformations. The method we propose has been tested on two sets of data, i.e., adults and children/young adults. For the first set of data, contours obtained automatically have been compared to contours delineated manually by three physicians. For the other set qualitative results are presented

Promoting advance planning for health care and research among older adults: A randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Family members are often required to act as substitute decision-makers when health care or research participation decisions must be made for an incapacitated relative. Yet most families are unable to accurately predict older adult preferences regarding future health care and willingness to engage in research studies. Discussion and documentation of preferences could improve proxies' abilities to decide for their loved ones. This trial assesses the efficacy of an advance planning intervention in improving the accuracy of substitute decision-making and increasing the frequency of documented preferences for health care and research. It also investigates the financial impact on the healthcare system of improving substitute decision-making.</p> <p>Methods/Design</p> <p>Dyads (<it>n </it>= 240) comprising an older adult and his/her self-selected proxy are randomly allocated to the experimental or control group, after stratification for type of designated proxy and self-report of prior documentation of healthcare preferences. At baseline, clinical and research vignettes are used to elicit older adult preferences and assess the ability of their proxy to predict those preferences. Responses are elicited under four health states, ranging from the subject's current health state to severe dementia. For each state, we estimated the public costs of the healthcare services that would typically be provided to a patient under these scenarios. Experimental dyads are visited at home, twice, by a specially trained facilitator who communicates the dyad-specific results of the concordance assessment, helps older adults convey their wishes to their proxies, and offers assistance in completing a guide entitled <it>My Preferences </it>that we designed specifically for that purpose. In between these meetings, experimental dyads attend a group information session about <it>My Preferences</it>. Control dyads attend three monthly workshops aimed at promoting healthy behaviors. Concordance assessments are repeated at the end of the intervention and 6 months later to assess improvement in predictive accuracy and cost savings, if any. Copies of completed guides are made at the time of these assessments.</p> <p>Discussion</p> <p>This study will determine whether the tested intervention guides proxies in making decisions that concur with those of older adults, motivates the latter to record their wishes in writing, and yields savings for the healthcare system.</p> <p>Trial Registration</p> <p><a href="http://www.controlled-trials.com/ISRCTN89993391">ISRCTN89993391</a></p

Produção e desenvolvimento de colônias de abelhas africanizadas (Apis mellifera l.) a partir de diferentes áreas e idades de cria Production and development of africanized honey bee (Apis mellifera l.) colonies departing from different comb brood areas and brood ages

A apicultura brasileira usa da captura de enxames silvestres de abelhas melíferas africanizadas (Apis mellifera L.) para repor e/ou aumentar o número de colônias dos apiários, possuindo inconvenientes como a dependência da natureza para captura dos enxames, a heterogeneidade genética das colônias capturadas e a possibilidade desses enxames serem portadores de doenças e parasitas prejudiciais à sanidade das abelhas. O presente trabalho testa e apresenta uma técnica de divisão de colônias de abelhas melíferas africanizadas para a produção de novas colônias fortes em curto espaço de tempo, a partir de recursos mínimos de cera, cria e alimento. Os resultados mostraram que núcleos de A. mellifera formados inicialmente com uma rainha jovem e fecundada, 1 kg de operárias, um quadro de cria fechada, um quadro de favo puxado e vazio e dois quadros com cera alveolada permitem a produção de novas colônias em 42 dias. Portanto, pode-se concluir que a técnica de divisão de colônias por formação de núcleos como descrito acima, oferece aos apicultores uma alternativa viável para a produção e comercialização em larga escala de novas colônias de abelhas melíferas africanizadas.<br>The Brazilian apiculture relies upon collecting wild swarms of Africanized honey bees (Apis mellifera L.) to replace and/or increase the number of colonies in the apiaries. This practice brings problems such as dependence on nature to capture any swarm, diverse genetic make-up of the colonies captured and the possibility of these swarms be carrying diseases and parasites harmful to the bees. The present work tests and presents a technique to split colonies of Africanized honey bees to produce new strong colonies in short time, departing from little resources of wax, brood and food stores. Results showed that A. mellifera nuclei formed by a young and mated queen, 1kg of workers, a frame of sealed brood, an empty frame of drawn beeswax and two frames containing an embossed sheet of beeswax each, allows producing new colonies within 42 days. Therefore, it is concluded that the technique to split colonies in nuclei as described above gives beekeepers a viable alternative to produce and commercialize new colonies of Africanized honey bees in large scale