Reconstructing institutional complexity in practice: A relational model of institutional work and complexity

This article develops a relational model of institutional work and complexity. This model advances current institutional debates on institutional complexity and institutional work in three ways. First, it provides a relational and dynamic perspective on institutional complexity by explaining how constellations of logics - and their degree of internal contradiction - are constructed rather than given. Second, it refines our current understanding of agency, intentionality and effort in institutional work by demonstrating how different dimensions of agency interact dynamically in the institutional work of reconstructing institutional complexity. Third, it situates institutional work in the everyday practice of individuals coping with the institutional complexities of their work. In doing so, it reconnects the construction of institutionally complex settings to the actions and interactions of the individuals who inhabit them

Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy

Background: The shift from conventional two-dimensional (2D) to three-dimensional (3D)conformal target definition and dose-planning seems to have introduced volumetric as well as geometric changes. The purpose of this study was to compare coverage of computed tomography (CT)-based breast and boost planning target volumes (PTV), absolute volumes irradiated, and dose delivered to the organs at risk with conventional 2D and 3D-conformal breast conserving radiotherapy. Methods: Twenty-five patients with left-sided breast cancer were subject of CT-guided target definition and 3D-conformal dose-planning, and conventionally defined target volumes and treatment plans were reconstructed on the planning CT. Accumulated dose-distributions were calculated for the conventional and 3D-conformal dose-plans, taking into account a prescribed dose of 50 Gy for the breast plans and 16 Gy for the boost plans. Results: With conventional treatment plans, CT-based breast and boost PTVs received the intended dose in 78% and 32% of the patients, respectively, and smaller volumes received the prescribed breast and boost doses compared with 3D-conformal dose-planning. The mean lung dose, the volume of the lungs receiving > 20 Gy, the mean heart dose, and volume of the heart receiving > 30 Gy were significantly less with conventional treatment plans. Specific areas within the breast and boost PTVs systematically received a lower than intended dose with conventional treatment plans. Conclusion: The shift towards CT-guided target definition and planning as the golden standard for breast conserving radiotherapy has resulted in improved target coverage at the cost of larger irradiated volumes and an increased dose delivered to organs at risk. Tissue is now included into the breast and boost target volumes that was never explicitly defined or included with conventional treatment. Therefore, a coherent definition of the breast and boost target volumes is needed, based on clinical data confirming tumour control probability and normal tissue complication probability with the use of 3D-conformal radiotherapy

25th Annual Computational Neuroscience Meeting: CNS-2016

Abstracts of the 25th Annual Computational Neuroscience Meeting: CNS-2016 Seogwipo City, Jeju-do, South Korea. 2–7 July 201

Accelerated Partial Breast Irradiation (APBI): A review of available techniques

Breast conservation therapy (BCT) is the procedure of choice for the management of the early stage breast cancer. However, its utilization has not been maximized because of logistics issues associated with the protracted treatment involved with the radiation treatment. Accelerated Partial Breast Irradiation (APBI) is an approach that treats only the lumpectomy bed plus a 1-2 cm margin, rather than the whole breast. Hence because of the small volume of irradiation a higher dose can be delivered in a shorter period of time. There has been growing interest for APBI and various approaches have been developed under phase I-III clinical studies; these include multicatheter interstitial brachytherapy, balloon catheter brachytherapy, conformal external beam radiation therapy and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include Mammosite, Axxent electronic brachytherapy and Contura, Hybrid brachytherapy devices include SAVI and ClearPath. This paper reviews the different techniques, identifying the weaknesses and strength of each approach and proposes a direction for future research and development. It is evident that APBI will play a role in the management of a selected group of early breast cancer. However, the relative role of the different techniques is yet to be clearly identified

Estimation of the centre of mass for the study of postural control in Idiopathic Scoliosis patients: a comparison of two techniques

The objective of the present study is to quantify the position of the Centre of Mass (COM) during quiet standing using a force plate and compare this technique to the quantification of the COM with an anthropometric model. The postural control of 18 healthy adolescents and 22 IS patients was evaluated using an Optotrak 3D kinematic system, and two AMTI force plates during quiet standing. The position of anatomical landmarks tracked by the Optotrak system served to estimate the position of the COM of both groups using an anthropometric model (COManth). The force plate served to estimate the position of the COM through double integration of the horizontal ground reaction forces (COMgl). The mean position and root mean square (RMS) amplitude of COMgl, in reference to the base of support (BOS) and the first sacral prominence (S1) were quantified in the Anterior–Posterior (A/P) and Medial–Lateral (M/L) directions. There was a significant difference between the control subjects and IS patients for the displacement of the COMgl in reference to the BOS in both the A/P and M/L directions. There was no difference between groups for the mean position of the COMgl, however, 63% of the IS and 43% of the controls had a lateral position of the COMgl in reference to S1 of greater than 5 mm. There was a significant difference between groups in the A/P and M/L directions for the amplitude of error between the COMgl and COManth techniques