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Planning and Dosimetric Comparisons of IMRT Lung Cancers with Three Advanced Optimization Algorithms
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作者 Yie Chen Jie Qu +3 位作者 Jack Yang mitch weiss Sang Sim Xiongfei Liao 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2013年第2期52-60,共9页
Purpose: To evaluate planning quality and dosimetric differences of clinically deliverable Intensity-modulated Radiation Therapy lung plans generated from Tomotherapy, Pinnacle3, and RayStationTM treatment planning sy... Purpose: To evaluate planning quality and dosimetric differences of clinically deliverable Intensity-modulated Radiation Therapy lung plans generated from Tomotherapy, Pinnacle3, and RayStationTM treatment planning systems. Method and Materials: Ten patients diagnosed with non-small-cell lung carcinoma (NSCLC) previously treated with plans on Pinnacle using Direct Machine Parameter Optimization were randomly selected and re-planned with Tomotherapy dose volume constraints and same beam geometry with RayStation Multi Criteria Optimization (MCO) equivalent uniform dose (EUD) or dose volume constraints, respectively.? Prescription was established as 60 Gy to cover > 95% of PTV. Planning outcomes such as D95 (95% of volume of PTV receiving the prescribed dose), D5, D33, mean heart and lung doses, V20 (volume of lung receiving 20 Gy), and max cord dose of 1cm3 were evaluated according to our departmental clinical protocols. Conformity index (CI = PTV / prescription isodose volume) and homogeneity index (HI = D5/D95) were also reported simultaneously. All plans were successfully uploaded for delivery verification. Results: Mean volume of calculated PTV was 356 ± 141 cm3. The planning results indicated that CI, HI, D95 and D5 of PTV, V20 of lung, and 1cm3 max cord dose were comparable but with better overall dosimetric distributions with conformity and homogeneity index from Tomotherapy plans in comparison to both Pinnacle and RayStation planning outcomes. Conclusions: Tomotherapy plans achieved better uniform tumor coverage with fewer hot spots while sparing more critical structures with superior dose fall-off. RayStation plans with MCO automatically generated a set of Pareto optimized solutions with given objectives to allow tradeoffs between targets and critical organs and tended to achieve better tumor coverage compared to Pinnacle. All three planning algorithms can generate clinical deliverable IMRT lung plans while Tomotherapy plans provide superior dosimetric indexes compared to Pinnacle and RayStation due to its unique beamlet optimization process with high modulation. 展开更多
关键词 MCO DMPO TOMOTHERAPY LUNG IMRT
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FIRPTA:投资美国易被忽视的房地产交易税收问题
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作者 Rob Rothenberg Jim Watson +2 位作者 mitch weiss George Graham 郑天成 《国际税收》 CSSCI 北大核心 2016年第9期50-53,共4页
近年来,越来越多的中国公司及个人投资者投资于美国的房地产及相关产业。在投资人取得收益时,美国的《境外投资者房地产税收法令》("FIRPTA")可能会对其产生较大的税务影响,但该影响在投资之前却常被投资人所忽视。对此,德勤... 近年来,越来越多的中国公司及个人投资者投资于美国的房地产及相关产业。在投资人取得收益时,美国的《境外投资者房地产税收法令》("FIRPTA")可能会对其产生较大的税务影响,但该影响在投资之前却常被投资人所忽视。对此,德勤团队详细分析了FIRPTA及其税务影响,并对中国投资者进行了风险提示。 展开更多
关键词 投资过程 税收问题 房地产交易 美国 中国公司 市场进入 退出策略 税收法规
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