Home About us Contact
|
Home About us Contact | ||
|
|
||
Hard Copies (hard + copy)
Selected AbstractsAccrediting radiation technique in a multicentre trial of chemoradiation for pancreatic cancerJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 6 2008N Spry Summary Before a multicentre trial of 3-D conformal radiotherapy to treat cancer of the pancreas, participating clinicians were asked to complete an accreditation exercise. This involved planning two test cases according to the study protocol, then returning hard copies of the plans and dosimetric data for review. Any radiation technique that achieved the specified constraints was allowed. Eighteen treatment plans were assessed. Seven plans were prescribed incorrect doses and two of the planning target volumes did not comply with protocol guidelines. All plans met predefined normal tissue dose constraints. The identified errors were attributable to unforeseen ambiguities in protocol documentation. They were addressed by feedback and corresponding amendments to protocol documentation. Summary radiobiological measures including total weighted normal tissue equivalent uniform dose varied significantly between centres. This accreditation exercise successfully identified significant potential sources of protocol violations, which were then easily corrected. We believe that this process should be applied to all clinical trials involving radiotherapy. Due to the limitations of data analysis with hard-copy information only, it is recommended that complete planning datasets from treatment-planning systems be collected through a digital submission process. [source] Diagnostic value of high signal abnormalities on T2 weighted MRI in the differentiation of Alzheimer's, frontotemporal and vascular dementiasACTA NEUROLOGICA SCANDINAVICA, Issue 5 2002A. R. Varma Objective ,,The occurrence of high signal abnormalities on T2 weighted images is strongly age related. The diagnostic value of these changes in a younger population with dementia is not currently known. We studied the potential of high signal changes on magnetic resonance imaging (MRI) in differentiating Alzheimer's disease (AD), frontotemporal dementia (FTD) and vascular dementia (VaD) in younger patients. Methods ,,High signal abnormalities were rated, using a previously validated scale, from hard copies of T2 weighted axial images of 102 patients with AD (n=49), VaD (n=31), FTD (n=22) (mean ages 63,65 years). Results ,,High signal abnormalities were widespread across AD, VaD and FTD. Although they were most frequent and most severe in the VaD group only lacunes and grade III deep white matter hyperintensities (DWMH) were specific for these patients. Conclusions ,,High signal changes on T2 weighted images on MRI are common across degenerative (AD and FTD) and vascular dementias. Although lacunes and grade III DWMH are specific for VaD, the low sensitivities (sensitivities: for lacunes, 0.32; for grade III DWMH, 0.16) limit their use as diagnostic markers for VaD. High signal changes on MRI should be interpreted with caution in dementias. Their presence, even in younger patients, should not deter one from diagnosing AD or FTD. [source] A simple and low-cost solution for the automation of X-ray powder diffractometers with chart recorder outputJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2006M. Jayaprakasan X-ray powder diffraction is an established method for the qualitative identification of crystalline materials and their quantitative analysis. The new generation of X-ray diffraction systems are based on expensive digital/embedded control technology and computer interfaces. Yet many laboratories use conventional manual-controlled systems with XY strip-chart recorders. Since the output spectrum is a strip chart (hard copy), raw data, essential for structural and qualitative analysis, are not readily available for further analysis. Upgrading to modern computerized diffractometers is very expensive. The proposed automation design described here is intended to enable the conventional diffractometer user to collect, store and analyze data quickly. The design also improves the resolution by five times compared with the conventional setup. For the automation, a PC add-on card has been designed to control and collect the timing and intensity counts from the conventional X-ray diffractometer, and suitable software has been developed to collect, process and present the X-ray diffraction data for both qualitative and quantitative analysis. Moreover, a major advantage of this design is that it does not warrant any physical modification of the hardware of the conventional setup; it is simply an extension to enhance the performance of collecting raw data with a higher resolution at desired intervals/timings. [source] Media-dependent color appearance modeling based on artificial neural networksCOLOR RESEARCH & APPLICATION, Issue 3 2006Binghua Chai Abstract In this study, we tried to consider various color appearance factors and device characterization together by visual experiment to simplify the across-media color appearance reproduction. Two media, CRT display (soft-copy) and NCS color atlas (hard-copy), were used in our study. A total of 506 sample pairs of RGB and HVC, which are the attributes of NCS color chips, were obtained according to psychophysical experiments by matching soft copy and hard copy by a panel of nine observers. In addition, a set of error back-propagation neural networks was used to realize experimental data generalization. In order to get a more perfect generalizing effect, the whole samples were divided into four parts according to different hues and the conversion between HVC and RHVCGHVCBHVC color space was implemented. The current results show that the displays on the CRT and the color chips can match well. In this way, a CRT-dependent reproduction modeling based on neural networks was formed, which has strong practicability and can be applied in many aspects. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 218,228, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20209 [source] | |||||||||||||