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1.

Purpose

This study aimed to investigate 3 planning target volume (PTV) margin expansions and determine the most appropriate volume to be used in bladder preservation therapy when using daily cone beam computed tomography (CBCT). We aimed to establish whether a smaller PTV expansion is feasible without risking geographical miss.

Methods and materials

The study included patients with bladder cancer who were treated with a hypofractionated course of radiation therapy delivered with intensity modulated radiation therapy. The clinical target volume (CTV) was the whole empty bladder, and the PTV consisted of a 1.5-cm margin around the bladder (PTV1.5 cm). Patients underwent daily CBCT imaging before treatment to assess the bladder volume and ensure accurate positioning. We investigated 2 additional smaller PTV margin expansions to determine the most appropriate volume to be used with CBCT as a daily image guided radiation therapy modality. These margins were created retrospectively on every CBCT. The first additional volume was a uniform PTV margin of the surrounding 1 cm (PTV1 cm). When considering that the majority of the internal bladder movement was due to the variation in filling that occurs in the superior and anterior directions, a second volume of an anisotropic PTV margin with a 1.5-cm superior/anterior and 1 cm in other directions (PTV1/1.5 cm) was created. We recorded the frequency and measured the volume of bladder falling out of each PTV based on the daily CBCT.

Results

For the purpose of this study, we considered an arbitrary 5 cm3 of CTV falling out of the designated PTV as a clinically significant volumetric miss. The frequency of such a miss when applying the uniform PTV1 cm was 1%. However, when applying the uniform PTV1.5 cm and anisotropic PTV1/1.5 cm margins, the frequency was 0.5% and 0.5%, respectively.

Conclusions

The anisotropic PTV expansion of 1.5 cm superiorly and anteriorly and 1 cm in all other directions around the bladder (CTV) provides a safe PTV approach when daily CBCT imaging is used to localize an empty bladder.  相似文献   
2.
Nerve growth factor (NGF) and NGF receptors were measured in cortex and hippocampus of rats treated with drugs affecting cholinergic neurotransmission. High (Kd= 0.045nM) and low (Kd= 21nM) affinity125I-NGF binding sites were present in both cortical and hippocampal membranes with hippocampus containing higher numbers of both sites than cortex. Chronic treatment of rats with the muscarinic receptor antagonist scopolamine (5 mg/kg, twice daily) decreased the density of high- and low-affinity sites by 50–90% in cortical and hippocampal membranes. These changes were seen after 7 days, but not 3 days, of scopolamine treatment. Chronic infusion of physostigmine (1 mg/kg/day) using minipumps increased the number of high- and low-affinity sites in cortex 3- and 6-fold, respectively. The changes in receptor-binding parameters induced by physostigmine were transient as they were evident after 3 days of treatment, but returned to control levels after 7 days. NGF content in cortex and hippocampus was reduced by about 50% following 7, but not 3, days of chronic physostigmine infusion. In contrast, scopolamine treatment failed to change NGF levels in the cholinergic neuronal target regions but it decreased NGF content in the septal area. The content of NGF mRNA in the cortex measured by Northern blot analysis failed to change following either scopolamine or physostigmine treatment. The results suggest that levels of NGF and NGF receptors in the target regions of cholinergic neurons are regulated by the extent of cholinergic neurotransmitter activity.  相似文献   
3.
In the cat synapses between vesicle containing profiles were observed in ventral and dorsolateral pontine nuclei. The presynaptic elements consisted of two types of axon terminals: axon terminals characterized by a population of small (38-40 nm) round synaptic vesicles (SSV) and axon terminals containing pleomorphic synaptic vesicles (PSV). The postsynaptic pale elements (PP) had pleomorphic vesicles and some features attributed to dendrites. In the dorsolateral pontine nucleus most of PP profiles took part in serial synapses, usually as an intermediate component, they were rarely observed in triads. On the basis of their electron microscopical appearance and synaptic relations they might be considered to represent a dendritic part of putative interneurons.  相似文献   
4.
Diagnostic validity of the criteria of myocardial ischemia in coronary patients exposed to the treadmill test is assessed. The risk of a false diagnosis of coronary insufficiency on the basis of the pain syndrome was 5 times as high as that of diagnosis based on ischemic electrocardiographic ST depression. In subjective assessment of walking tolerance, patients with severe angina were particularly prone to mistakes. Limitations of angina classifications by severity, based on subjective sensations of coronary patients, are considered.  相似文献   
5.
Based on the experience with treatment of 26 patients the authors recommend to use mainly conservative treatment with the intrapleural administration of fibrinolytic drugs. The method was used in 20 patients. All of them recovered.  相似文献   
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8.
The authors describe results of using endoscopic papillosphincterotomy in 100 patients with acute pancreatitis. Methods of endoscopic papillosphincterotomy and endoscopic papillosphincterowirsungotomy are presented. The effectiveness of the treatment was 96%. Operative procedures on emergency made up 1%, lethality-1%, complications-3% of the cases.  相似文献   
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10.
A method of diagnostics and assessment of the severity of arterial insufficiency of lower extremities was developed on the basis of multistep treadmill-test and measuring time of reestablishment of continuous bloodflow in the popliteal artery by the method of ultrasonic doppler flowmetry. An examination of 40 patients with angiographically detected alterations of the vessels and 18 healthy persons was performed. It was found that the diagnostic and assessment criterion of arterial insufficiency in treadmill-test with high parameters of sensitivity and specificity is longer duration of the period of reestablishment of continuous bloodflow over 180 sec. The arterial insufficiency severity is estimated by the value of exercise by the moment of the appearance of the criterion.  相似文献   
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