Abstract: With the aid of Thermoluminescent Dosimeter, survey client entrance surface dose (ESD) level caused by three main chest X-ray photography equipment in Hunan province. By stratified sampling method, 35 hospitals are selected, 607 cases of client are selected totally. Through the comparison of ESD caused by different types of equipment, in different level of hospitals, on different modes of kV, come to the following preliminary conclusions: for chest X-ray photography, the average ESD caused by high kV mode is lower than low kV mode; due to the different processing capacity of common X-ray, CR, DR imaging, the ESD caused by the three kinds of equipment usually follow the rule of X-ray machine > CR > DR; the current distribution status of these three equipment in different scale hospitals, to a certain level, can reflect average ESD caused by chest X-ray photography in different level hospitals following the rule of primary hospital> secondary hospital > tertiary hospital. Ordinary X-ray photography brings a greater risk of radiation to the client. When use it to do chest X-ray photography on client, physicians should do well indications analysis. At the same time, on the premise of no affecting to diagnosis, the staff should select appropriate exposure conditions according to the principle of “high voltage, low current, thick filter, little radiation field”.

Key words: regular voltage, chest X-ray radiography, ESD