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| Research on Measurement System for Medium-energy X-rays Absorbed Dose to Water |
| FAN Song1,WU Jin-jie1,WANG Kun1,WANG Zhi-peng1,2,ZHAO Rui1 |
1. National Institute of Metrology, Beijing 100029, China
2. Beijing Jiaotong University, Beijing 100044, China |
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Abstract Medium-energy X-rays are mainly used for radiation diagnosis of cancer and radiotherapy of deep or superficial tumors. Absorbed dose to water is characterized by the physical quantity that X-rays are deposited in the human body. Three are currently three methods for measuring absorbed dose to water of X-rays, such as calorimetry, ionization and chemical dosing. The hydrothermal method is to determine the dose absorbed to water by measuring the temperature rise caused by the energy deposition of radiation beams in water. In order to measure the medium-energy X-ray water absorption dose, five X-ray radiation matters of (100~220) kV for radiotherapy were established, and the dose absorbed to water under each radiation was directly measured by a cavity cylindrical hydrocalorimeter. The method initially realizes the absolute measurement of the dose absorbed to water for the medium energy X-rays, and provides a basis for establishing the dose absorbed to water of the medium energy X-rays primary or second standard device.
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2018, Vol. 39 
