【摘要】 目前新型可移动式低能光子放射治疗设备INTRABEAM的应用越来越广泛。针对该设备产生的X射线剂量特性研究甚少，为准确掌握其在组织内的剂量分布带来一定挑战。针对INTRABEAM系统产生的X射线在空气和水中的剂量学特征进行研究。利用MCNP6中增加的原子弛豫过程，对产生的光子能谱、百分深度剂量曲线和近距离治疗剂量参数（二维各向异性函数和径向剂量分布）进行计算研究。结果表明，模拟得到的空气中注量谱有精细的电子跃迁特征峰，在空气中30 cm处平均能量为20.0 keV，产生百分剂量深度接近x–3变化趋势；二维各向异性函数由Be管壁靠近Ni管壁中变化趋势出现转折，径向剂量函数在小于10 mm处出现陡降，而后变化相对缓慢。利用蒙卡方法计算的TG-43文件中必要数据为临床剂量计算使用的治疗计划系统提供参考方法和数据，便于在术中放射治疗进行有效剂量计算。更多还原

【Abstract】 The new mobile equipment with low energy photon is widely used in the interstitial treatment of small tumors. Up do date, there is little research on the dosimetric characteristics of the INTRABEAM X-ray,which brings some challenges to master the distribution of the dose distribution in the tumor accurately. The aim of the research is to study the dosimetric characteristic in air and water of the X-ray produced by the INTRABEAM. The photon spectrum, percentage depth dose and the dose parameters of bare probe of INTRABEAM(2D anisotropy function and radial dose function) were calculated by using Monte Carlo software added the function of atomic relaxation process. From the study results, the fluence spectrum was obtained in the air with the fine electron transition characteristic peaks. The average energy is 20.0 keV at the30 cm distance in the air. The trend of the Percentage Depth Dose varied close to x–3. The variation trend of the2D anisotropy function was changed from the Be-made tube to the Ni-made tube. The radial dose function showed a steep fall-off close to the probe within 10 mm and subsequently the change was relatively slow.These results is of great importance in the TG-43 report, which can provide data reference for commercial treatment planning system to calculate the dose distribution in intraoperative radiotherapy.更多还原