Purpose:The aim of this study is to investigate a new type of imaging technique of using the 11 C and 15 O positron nuclear emission while high energy X-Ray(50 MV)irradiate on patients.Using this information to further quantitative discuss dose delivery and accuracy of the irradiated tumor biological targets.Methods:According to procedures of conventional radiotherapy,A Plexglass phantom position was firstly verified by PET/CT and the phantom was irradiated by three different energies(10MV,25MV and 50MV)with various 1Gy-10Gy dosages X-Rays on MM50 accelerator.The accelerator also planned three irradiation fields in Treatment Planning System(TPS).As Carbon and Oxygen are the two main elements of the human body,we only investigate the imaging form of 11 C and 15 O this time.After irradiation,PET immediately scanned the phantom for data analyzing.In the scanned images,we analyzed radiation field tracks,the scale of irradiation area and compared them with physical radiation field area.After determined 11 C activity distribution,we examined the relationship between 11 C imaging position,imaging intensity,irradiation field,and irradiation dosage.Results:50MV X-Ray with 2Gy irradiation could acquire clearly 11 C image on PET and have capabilities to accurate analysis irradiation tracks and irradiation position with precise of 1mm.In the direction of radiation ray off-axis,activity curve of 11 C was consistent with the TPS calculated dose curve.However,in the direction of radiation ray axis,the activity curve of 11 C had a big difference with the TPS calculated depth dose curve.Conclusion:The positron nuclear emission 11 C that generated by photon-nuclear reaction with 2Gy 50MV X-Ray irradiating on the phantom can acquire clearly scanning images on PET.The imaging positions able to biological validate the accuracy of the irradiated target.