MRI image-based FE modelling of the pelvis system and bladder filling.

In this study, high-resolution magnetic resonance imaging was performed in the transaxial, coronal and sagittal planes to provide comprehensive structural details of the bladder and surrounding systems. Detailed finite-element (FE) models that were specific to each participant were developed by rendering the images, and the process of bladder filling was simulated. The overall model of bladder deformation was compared with repeated images of the filled bladder that were obtained using computed tomography to validate the FE models. The relationship between the changes in the key dimensions of the bladder and the increase in bladder volume during the filling process was also investigated. The numerical results showed that the bladder dimensions increased linearly with its volume during the filling process and the predicted coefficients are comparable to some of the published clinical results.

Escalation and intensification of radiotherapy for stage III non-small cell lung cancer: opportunities for treatment improvement.

In this overview we review and model how radiotherapy tumour control and complication rates vary with dose, fractionation, schedule duration, irradiated volume and use of chemotherapy for stage III non-small cell lung cancer (NSCLC), and use the modelling to study the effectiveness of different NSCLC dose-escalation approaches being developed in the UK. Data have been collated for pneumonitis, lung fibrosis, early and late oesophagitis, cord and cardiac complications, and local progression-free survival at 30 months. Dependences of the various end points on treatment-related factors are catalogued and analysed using the linear-quadratic incomplete repair model to account for dose and fractionation effects, making linear corrections for differences in schedule duration, and loosely characterising volume effects using parallel- and series-type concepts. Tolerance limits are calculated for the different end points and distilled into ranges of prescribed dose likely to be tolerable when delivered in 2.5 and 4 week radiation and 6 week chemoirradiation schedules using conformal techniques. Worthwhile ( approximately 20%) gains in 30 month local progression-free survival should be achievable at safely deliverable levels of dose escalation. The analysis suggests that longer schedules may be more beneficial than shorter ones, but this finding is governed by the relative rates of tumour and oesophageal accelerated proliferation, which are quite imprecisely known. Consequently escalated 2.5, 4 and 6 week schedules are being developed; each should lead to useful improvements in local control but it is not yet known which schedule will be most effective.

Vascular control of the renal pedicle using the hem-o-lok polymer ligating clip in 50 consecutive hand-assisted laparoscopic nephrectomies.

BACKGROUND AND PURPOSE: A crucial step in laparoscopic nephrectomy is control and ligation of the renal pedicle. Commonly, an endovascular gastrointestinal anastomosis (GIA) stapling device, titanium staples, or both is employed for vascular control. Herein, we report on the use of the Hem-o-Lok polymer ligating clip (Weck Closure Systems, Research Triangle Park, NC) for the routine control of the renal pedicle (both venous and arterial) during hand-assisted laparoscopic radical nephrectomies. PATIENTS AND METHODS: From March 2001 to December 2002, 50 hand-assisted simple or radical nephrectomies were performed by a single surgeon. The Hem-o-lok polymer ligating clip was utilized exclusively for ligation of the renal pedicle, with placement of two clips on the patient's side and one distally on the specimen side. RESULTS: Vascular control was achieved safely in all cases. Neither slippage nor complications were found in any of these cases. CONCLUSIONS: Vascular control of the renal pedicle via the Hem-o-Lok polymer ligating clip is safe and dependable for laparoscopic radical/simple nephrectomies.