检索结果-南通市图书馆

Effects of Beam Startup Characteristics on Dose Delivery Accuracy at Low Monitor Units in step-and-shoot Intensity Modulated Radiation Therapy

引用

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2013年第1期2卷 1-5页

作者： Kazunori Fujimoto Kunihiko Tateoka Yuji Yaegashi Katsumi Shima Junji Suzuki Yuichi Saito Akihiro Nakata Takuya Nakazawa Tadanori Abe Masaki Yano Masanori Someya Kensei Nakata Masakazu Hori Masato Hareyama Koichi Sakata Department of Medical Physics Graduate School of Medicine Sapporo Medical University Sapporo Japan Department of Radiology Sapporo Medical University Sapporo Japan Radiation Therapy Research Institute Social Medical Corporation Teishinkai Sapporo Japan

Intensity modulated radiation therapy (IMRT) is a highly accurate technique that is usually implemented in either dynamic or step-and-shoot fashion with many segments each having low monitor units (MUs). The present study evaluated the effects of beam startup characteristics on the dose delivery accuracy for each segment at low MUs for step-and-shoot IMRT with an Elekta Precise accelerator at the highest dose rates. We used a two-dimensional semi-conductor detector for the dose measurements. The field size of each segment was assumed to be 20 ×20 cm2 and each segment was set to deliver 1 - 10 MUs. Our results show a variation in dose delivery accuracy between segments for the same IMRT beam, which can be attributed to the beam startup characteristics. This variability is attributed to the changes in the transient changes in the temperatures of the electron gun filament and the magnetron. That is, the transient increase in the temperature of the filament leads to increasing doses with time and that of the magnetron leads to decreasing doses with time during the first few MUs.

关键词： Startup Performance step-and-shoot IMRT Low Monitor Units

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Beam Characteristics at Low Dose Monitor Unit Settings for Vero4DRT

引用

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2015年第4期4卷 284-289页

作者： Hideharu Miura Shuichi Ozawa Shintaro Tsuda Masahiro Hayata Kiyoshi Yamada Yasushi Nagata Hiroshima High-Precision Radiotherapy Cancer Center Hiroshima Japan Department of Radiation Oncology Institute of Biomedical & Health Science Hiroshima University Hiroshima Japan

The stability of delivery of low monitor unit (MU) setting is important especially for step-and-shoot intensity-modulated radiotherapy (IMRT), because the nature of the technique is inherent to repeat beam on/off according to the number of the segments. This study evaluates the dose linearity and profile flatness/symmetry under low MU settings for Vero4DRT, a new linear-accelerator based irradiation system that currently implements step-and-shoot IMRT. To evaluate the dose linearity and flatness/symmetry, the point doses and beam profiles were measured as functions of MU and dose rates. The accuracy of dose delivery depended on the dose rate. Under all dose rates, the dose was linear within 1% above 5 MU and within 2% above 3 MU. The beam symmetry was degraded in-line compared with crossline, although both profiles were symmetric within 2% at all dose settings. The profile flatness was also within 2% above 5 MU at any dose rate and showed no significant variation among the low MU settings. To ensure stable beam delivery without increasing the treatment time of Vero4DRT, we recommend a delivery of 5 MU per segment at a dose rate of 500 MU/min.

关键词： Vero4DRT step-and-shoot IMRT Low Monitor Unit Beam Characteristic

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：