针对无均整器(FFF)光子束，建立一种描述光子束的射野离轴比(OAR)曲线特性的新方法，无需借助有均整器光子束，即可独立描述FFF光子束的射野离轴比特性的方法，该方法能计算FFF光子束的射野大小，可用高斯函数拟合FFF光子束的OAR曲线形状。
", "ds_source": "对无均整器(FFF)光子束，建立一种描述其射野离轴比(OAR)曲线特性的新方法。方法用扫描水箱测量得到Varian Edge、Elekta VersaHD、Tomotherapy三类治疗机在FFF模式下1．5、5．0、10．0、20．0 am深度处的OAR曲线，然后分别由野内向野外、由野外向野内求离轴比的二\n次导数．前者的最大值和后者的最小值所在位置连线的中点定义为射野边界。左右两侧射野边界之间的距离定义为剂量学射野大小。用高斯函数对80％射野范围内的OAR曲线进行拟合，拟合所得参数用于描述OAR形状特点。结果用新方法计算得到的射野大小误差<0．11 cm，射野中心误差<0．05cm。用高斯函数拟合OAR曲线时，拟合相关系数>0．998。OAR曲线拟合误差随深度的变化不明显，但随射野增大略有增加，10、20、30、40 cm射野时拟合最大误差分别为0．49％、0．67％、1．25％、2．52％。建立一种无需借助有均整器光子束即可独立描述FFF光子束射野离轴比特性的方法。该方\n法能计算FFF光子束射野大小，可用高斯函数拟合FFF光子束OAR曲线形状。
", "ds_process_way": "用扫描水箱测量得到Varian Edge、Elekta VersaHD、Tomotherapy三类治疗机在FFF模式下1．5、5．0、10．0、20．0 am深度处的OAR曲线，然后分别由野内向野外、由野外向野内求离轴比的二次导数。前者的最大值和后者的最小值所在位置连线的中点定义为射野边界。左右两侧射野边界之间的距离定义为剂量学射野大小。用高斯函数对80％射野范围内的OAR曲线进行拟合，拟合所得参数用于描述OAR形状特点。
", "ds_quality": "数据质量良好
", "ds_acq_start_time": "2017-07-01 00:00:00", "ds_acq_end_time": "2019-12-31 00:00:00", "ds_acq_place": "甘肃兰州", "ds_acq_lon_east": null, "ds_acq_lat_south": null, "ds_acq_lon_west": null, "ds_acq_lat_north": null, "ds_acq_alt_low": null, "ds_acq_alt_high": null, "ds_share_type": "apply-access", "ds_total_size": 806840, "ds_files_count": 2, "ds_format": "pdf", "ds_space_res": null, "ds_time_res": "", "ds_coordinate": "无", "ds_projection": "", "ds_thumbnail": "1ecb9b42-9d2d-4ba8-b8a5-33dbf8ce9860.png", "ds_thumb_from": 0, "ds_ref_way": "", "paper_ref_way": "", "ds_ref_instruction": "", "ds_from_station": null, "organization_id": "9971252d-7beb-4464-bc08-bdcc5a1d7dd1", "ds_serv_man": "敏玉芳", "ds_serv_phone": "0931-4967596", "ds_serv_mail": "ncdc@lzb.ac.cn", "doi_value": "", "subject_codes": [], "quality_level": 3, "publish_time": "2023-08-25 09:38:55", "last_updated": "2023-08-28 15:45:03", "protected": false, "protected_to": null, "lang": "zh", "cstr": "11738.11.NCDC.IMP.DB3936.2023", "i18n": { "en": { "title": "A method for describing the characteristics of a photonic beam without a homogenizer", "ds_format": "", "ds_source": "A new method is proposed to describe the off-axis ratio (OAR) curve of FFF photon beam. Methods the oar curves at 1.5, 5.0, 10.0 and 20.0 am depth of Varian edge, Elekta versahd and tomotherapy were measured by scanning water tank, and then the off-axis ratio was calculated from field to field and from field to field respectively\nThe midpoint of the line between the maximum of the former and the minimum of the latter is defined as the field boundary. The distance between the left and right field boundaries is defined as the dose field size. Gaussian function is used to fit the oar curve in the range of 80% field, and the fitting parameters are used to describe the shape characteristics of oar. Results the error of field size and center was less than 0.11 cm and 0.05 cm respectively. When the oar curve was fitted with Gaussian function, the fitting correlation coefficient was more than 0.998. The fitting error of oar curve did not change obviously with the depth, but increased with the increase of the field. The maximum fitting error of 10 cm, 20 cm, 30 cm and 40 cm field was 0.49%, 0.67%, 1.25% and 2.52% respectively. A method is proposed to describe the off-axis ratio of FFF photon beam without the aid of a homogenizer. The party\nThe method can calculate the field size of FFF photon beam and fit the oar curve shape of FFF photon beam with Gaussian function.
", "ds_quality": "Good data quality
", "ds_ref_way": "", "ds_abstract": "A new method is proposed to describe the off-axis ratio (OAR) curve of FFF photon beam. The method can describe the off-axis ratio of FFF photon beam independently without the aid of equalizer photon beam. The method can calculate the field size of FFF photon beam and fit the oar curve shape of FFF photon beam with Gaussian function.
", "ds_time_res": "", "ds_acq_place": "", "ds_space_res": "", "ds_projection": "", "ds_process_way": "The oar curves of Varian edge, Elekta versahd and tomotherapy at 1.5, 5.0, 10.0 and 20.0 am in FFF mode were measured by scanning water tank, and then the two values of off-axis ratio were calculated from field to field and from field to field respectively\nSecond derivative. The midpoint of the line between the maximum value of the former and the minimum value of the latter is defined as the field boundary. The distance between the left and right field boundaries is defined as the dose field size. Gaussian function is used to fit the oar curve in the range of 80% field, and the fitting parameters are used to describe the shape characteristics of oar.
", "ds_ref_instruction": "" } }, "submit_center_id": "ncdc", "data_level": 0, "license_type": "CC BY 4.0", "doi_reg_from": "reg_local", "cstr_reg_from": "reg_local", "doi_not_reg_reason": null, "cstr_not_reg_reason": null, "is_paper_in_submitting": false, "ds_topic_tags": [ "无均整器光子束", "射野大小" ], "ds_subject_tags": [], "ds_class_tags": [], "ds_locus_tags": [ "兰州", "甘肃省" ], "ds_time_tags": [ 2017, 2018, 2019 ], "ds_contributors": [ { "true_name": "肖国青", "email": "xiaogq@impcas.ac.cn", "work_for": "中国科学院近代物理研究所", "country": "中国" } ], "ds_meta_authors": [ { "true_name": "肖国青", "email": "xiaogq@impcas.ac.cn", "work_for": "中国科学院近代物理研究所", "country": "中国" } ], "ds_managers": [ { "true_name": "肖国青", "email": "xiaogq@impcas.ac.cn", "work_for": "中国科学院近代物理研究所", "country": "中国" } ], "category": "其他" }