摘要医用电子直线加速器的吸收剂量校准是放射治疗质量控制最重要的内容之一，特别是当前普遍开展的精准放疗，对吸收剂量测定的精度提出了更高要求。基于水吸收剂量校准因子的吸收剂量测定规程，相对基于空气比释动能/照射量校准因子的吸收剂量测定规程，具有吸收剂量测定不确定度更小、无需量的转换计算、物理概念更简单、计算公式更简化等优势。本指南参考国内外相关标准，对医用直线加速器高能射束基于水吸收剂量校准因子的吸收剂量测定方法及相关要求作出了规定，为国内医疗机构基于水吸收剂量校准因子测定外照射高能光子束和高能电子束的吸收剂量提供指导，为精确放疗的广泛开展提供支持。

abstractsThe calibration of absorbed dose of medical electronic linear accelerator is one of the most important contents of radiotherapy quality control. In particular, the widespread application of precision radiotherapy puts forward higher requirements for the accuracy of radiotherapy dosimetry. Compared with the absorbed dose dosimetry procedure based on calibration factor in terms of air kerma/exposure, the advantages of the absorbed dose dosimetry based on calibration factor in terms of absorbed dose to water are: reduced uncertainty, no quantity conversion factors, simpler physical concept and simpler calculation formula, etc. According to relevant existing standards, this guideline specifies the dosimetry procedures and relevant requirements for high-energy beams of medical linac based on calibration factor of absorbed dose to water, provides guidance for domestic medical institutions to determine the absorbed dose of high-energy photon and electron beams, and provides support for the development of precision radiotherapy.