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基于URQ模型的I帧码率控制
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作者 王朋 倪翠 +1 位作者 张广渊 李克峰 《应用科学学报》 CAS CSCD 北大核心 2015年第1期70-78,共9页
当目标码率较低时,在编码视频序列中周期性地插入I帧,会导致重建视频播放时出现"闪烁"现象.为提高I帧重建质量,抑制"闪烁",提出了一种基于URQ模型的I帧码率控制算法.首先根据图像的运动趋势和复杂度将I帧划分为运... 当目标码率较低时,在编码视频序列中周期性地插入I帧,会导致重建视频播放时出现"闪烁"现象.为提高I帧重建质量,抑制"闪烁",提出了一种基于URQ模型的I帧码率控制算法.首先根据图像的运动趋势和复杂度将I帧划分为运动区域、图像复杂区域和平坦区域;然后依据人眼视觉系统对不同区域"闪烁"的敏感性,为视觉敏感区域分配更多的码率,其他区域分配较少码率;最后,利用URQ模型计算编码所需的量化参数值,实现对I帧的码率控制.实验结果表明,所提算法能够在保证码率控制精度的前提下,有效抑制由于周期性插入I帧导致的视频"闪烁"现象,提高重建视频的整体主客观质量. 展开更多
关键词 URQ模型 “闪烁”抑制 I帧 码率控制
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Somatostatin receptor subtype 2-mediated scintigraphy and localization using ^(99m)Tc-HYNIC-Tyr^3-octreotide in human hepatocellular carcinoma-bearing nude mice 被引量:2
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作者 YongLi Jian-MingSi +3 位作者 JunZhang JinDu FanWang BingJia 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第25期3953-3957,共5页
AIM: To investigate the uptake of 99mTc-HYNIC-Tyr3-octreotide (99mTc-HYNIC-TOC) in human hepatocellular carcinoma (HCC), which can provide the localizable diagnosis in hepatic carcinoma. METHODS: The expression of som... AIM: To investigate the uptake of 99mTc-HYNIC-Tyr3-octreotide (99mTc-HYNIC-TOC) in human hepatocellular carcinoma (HCC), which can provide the localizable diagnosis in hepatic carcinoma. METHODS: The expression of somatostatin receptor 2 (SSTR2) messenger RNA (mRNA) in human HCC cell line HepG2 was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Uptake of 99mTc-HYNIC-TOC was evaluated in the human HCC implanted into BALB/c nude mice. ANMIS2000 nuclear medicine analysis system was used to calculate the ratio of 99mTc uptake between tumor tissue and vital organs. RESULTS: We demonstrated the expression of SSTR2 mRNA in human HCC cell line HepG2 by RT-PCR. The size of the RT-PCR products was 364 bp detected by sequence analysis of the human SSTR2 mRNA. Scintigraphy proved that 99mTc-HYNIC-TOC was uptaken in the tumor tissue, liver and kidney of the tumor-bearing mice. CONCLUSION: Based on expression of the SSTR2 mRNA in human HCC, 99mTc-HYNIC-TOC can markedly bind with and be uptaken by human HCC tissues as compared with normal liver tissue. The significant retention of radionudide in kidney and bladder is probably related to non-specific peptide uptake in the tubulus cells of kidney and possibly due to excretion by kidney. Our results show that localizable diagnosis and targeting radiotherapy with radionuclide-labeled somatostatin analog for HCC are of great value to be further studied. 展开更多
关键词 Hepatocellular carcinoma 99mTc-HYNIC-Tyr3-octreotide Somatostatin receptor 2
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A “false positive” octreoscan in ileal Crohn’s disease
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作者 Alberto Fernandez Olga Tabuenca Angeles Peteiro 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5349-5352,共4页
We present a case report of a patient with a suspicious ileal carcinoid tumour. Clinical examination as well as computer tomograghy (CT) scan suggested a tumour. Octeotride scan showed uptake in the same bowel loop re... We present a case report of a patient with a suspicious ileal carcinoid tumour. Clinical examination as well as computer tomograghy (CT) scan suggested a tumour. Octeotride scan showed uptake in the same bowel loop reported as pathological in CT. The patient underwent surgery and biopsy which reported Crohn’s disease (CD). The interest in the case is due to the fact that this is, to the best of our knowledge, the second report of Crohn’sdisease as a cause of false positive octeotride scan. Unfortunately, no somatostatin recptors could be found in the sample, so further studies should be performed. 展开更多
关键词 Crohn's disease Carcinoid tumour OCTREOSCAN Somatostatin receptor scintigraphy ^111In-DTPA- octreotido
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