中能X射线水吸收剂量量值复现方法研究

Research on Measurement System for Medium-energy X-rays Absorbed Dose to Water

中能X射线应用于癌症的辐射诊断和深、浅层肿瘤的治疗,而X射线沉积在人体内的辐射剂量用水吸收剂量表征。现有的中能X射线水吸收剂量的测量方法有量热法、电离法和化学剂量法,水量热法是通过测量某种辐射射束在水中的能量沉积引起的温升来确定其水吸收剂量。为了测量中能X射线水吸收剂量,建立了100~220kV下的5个治疗水平X射线辐射质,用空腔圆柱型水量热计直接测量了各辐射质下的水吸收剂量。初步实现了中能X射线水吸收剂量的量值复现,为建立中能X射线水吸收剂量基准或标准装置提供了基础。

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.