Mucosal dose prescription in endobronchial brachytherapy: a study based on CT-dosimetry

Purpose: To investigate the consequences of using different dose prescription methods for endobronchial brachytherapy (EB), both with and without the use of a centered applicator.Materials and Methods: A CT scan was performed during EB procedures in 13 patients after insertion of the lung applicator. A dosimetric analysis was subsequently performed in five of these patients using a 3D-brachytherapy treatment planning system (PLATO v13.3, Nucletron). Results: Dose prescription to the mucosa yields uniform dose distributions to the bronchial mucosa when a centrally positioned applicator is used. When non-centrally positioned applicators are used, mucosal dosing results in a significant underdosage to parts of the target volume. Due to the rapid dose fall-off in EB, dose prescription to the mucosa resulted in inadequate coverage of the outer portion of the bronchial wall and adjacent peribronchial space. When compared to mucosal dose prescription, prescription to the outer aspect of the bronchial wall appears to improve target coverage while limiting the hyperdose (i.e., 200%) volume. The diameters of the different bronchial segments, as determined by CT measurements in 13 patients, correlated well with calculated values based upon the tracheal diameter. Conclusions: Mucosal dose prescription should only be used in combination with centered EB applicators. Given the rapid dose fall-off in EB mucosal dose prescription should be used with caution in curative treatments where EB, without additional external radiotherapy, is used as the sole treatment modality. In curative EB, both improved target coverage and a limited hyperdose volume can be achieved by dose prescription to the outer aspect of the bronchial wall. Copyright (C) 2000 Elsevier Science Inc

Small bowel involvement in Crohn’s disease: a prospective comparison of wireless capsule endoscopy and computed tomography enteroclysis

Background: Wireless capsule endoscopy (WCE) offers endoscopic access to the small bowel and may therefore change diagnostic and therapeutic strategies in small bowel diseases. Aim: The aim of this prospective study was to validate the gain in information and therapeutic impact of WCE in patients with Crohn’s disease. Methods: Fifty six consecutive patients with Crohn’s disease underwent computed tomography (CT) enteroclysis, and if stenoses <10 mm were excluded, WCE was carried out. Results: In 15 patients (27%), WCE could not be performed due to strictures detected by CT enteroclysis. From the other 41 patients, jejunal or ileal lesions were found in 25 patients by WCE compared with 12 by CT enteroclysis (p = 0.004). This gain in information was mainly due to detection of small mucosal lesions such as villous denudation, aphthoid ulcerations, or erosions. Both methods were not significantly different in the detection of lesions in the terminal/neoterminal ileum (WCE 24 patients, CT enteroclysis 20 patients). Therapy was changed due to WCE findings in 10 patients. Consecutively, all of them improved clinically. Conclusions: Capsule endoscopy improves the diagnosis of small bowel Crohn’s disease. This may have significant therapeutic impact

Walking the neighbourhood, seeing the small details of community life: reflections from a photography walking tour

This paper examines the value of photography walking tours for exploring meanings and experiences of community. The work is part of a larger visual research project which sought to examine the everyday lives of residents in a neighbourhood identified as ‘disadvantaged’, with the tour being organized as an opportunity for residents to identify what they valued about their local environment and what they considered to be problematic. The dynamics involved in gathering this photographic record are one element of the discussion as is analysis of the ways in which the participants constructed and re-constructed their sense of community through the different examples they selected for photographing. The paper is thus concerned with the ways in which visual data bring different insights to understandings of which practices, services and resources are embedded in meanings of community in working-class neighbourhoods and, in turn, how such data might have value for informing policy and practice about the experiences of inequality in contemporary England

Customized computed tomography-based boost volumes in breast-conserving therapy: use of three-dimensional histologic information for clinical target volume margins

PURPOSE: To determine the difference in size between computed tomography (CT)-based irradiated boost volumes and simulator-based irradiated volumes in patients treated with breast-conserving therapy and to analyze whether the use of anisotropic three-dimensional clinical target volume (CTV) margins using the histologically determined free resection margins allows for a significant reduction of the CT-based boost volumes. PATIENTS AND METHODS: The CT data from 49 patients were used to delineate a planning target volume (PTV) with isotropic CTV margins and to delineate a PTV(sim) that mimicked the PTV as delineated in the era of conventional simulation. For 17 patients, a PTV with anisotropic CTV margins was defined by applying customized three-dimensional CTV margins, according to the free excision margins in six directions. Boost treatment plans consisted of conformal portals for the CT-based PTVs and rectangular fields for the PTV(sim). RESULTS: The irradiated volume (volume receiving > or =95% of the prescribed dose [V(95)]) for the PTV with isotropic CTV margins was 1.6 times greater than that for the PTV(sim): 228 cm(3) vs. 147 cm(3) (p < .001). For the 17 patients with a PTV with anisotropic CTV margins, the V(95) was similar to the V(95) for the PTV(sim) (190 cm(3) vs. 162 cm(3); p = NS). The main determinant for the irradiated volume was the size of the excision cavity (p < .001), which was mainly related to the interval between surgery and the planning CT scan (p = .029). CONCLUSION: CT-based PTVs with isotropic margins for the CTV yield much greater irradiated volumes than fluoroscopically based PTVs. Applying individualized anisotropic CTV margins allowed for a significant reduction of the irradiated boost volume