| Part I.Calibration of TLD and measurement of absorbed dose in radiation-induced liver injury modelsObjective:To seek the feasibility of constructing a small animal precision radiotherapy model under linear accelerator precision radiotherapy by applying a thermoluminescent detector（TLD）for dose detection at the irradiated site of a mouse liver.Methods:TLDs with dispersion and reproducibility errors<1.5%were screened by irradiating 5 MU of TLDs with a linear accelerator,and the TLDs that had been screened and annealed were irradiated with 5,30,50,70,100,150,200,and 300 MU to find out the calibration factor of the batch of TLDs.A volumetric rotational intensity-modulated radiotherapy（VMAT）plan with a prescribed dose of 2 Gy and 360°arc was developed using the planned target volume（PTV）at the location of the TLD within the solid water,and the difference between the measured dose of TLD and the evaluated parameters in the TPS system was compared.The TLD was implanted into the liver of mice,and a VMAT plan with a prescription dose of 2 Gy and 360°arc was designed using the location of the TLD in the mouse liver as the PTV,and the difference between the measured dose of TLD and the prescription dose in the TPS system was compared.Results:TLD had a linear dose-response under the linear accelerator,with measured values of solid underwater TLD within±3%of the D mean value of the parameter evaluated in the TPS system,and deviations of-1.5%to 6%between measured and prescribed doses of TLD in the mouse liver.Conclusions:It is feasible to construct a precise mouse model of radiation-induced liver injury（RILD）using the VMAT technique under a linear accelerator.Part II.Establishment of a mouse model of radiation-induced liver injury under precise radiotherapyObjective: To construct a biologically accurate model of radiation-induced liver injury（RILD）in mice by irradiating the mouse liver locally with a single high dose（SBRT）,and to provide a reliable and stable animal study model for exploring the molecular pathogenesis of RILD.Methods: Fifteen SPF-rated C57BL/6J male mice of 6-8 weeks of age were randomly divided into a control group（no radiation treatment）and radiation group（30 Gy radiation,and 35 Gy radiation treatment）,and their survival rate was observed for 20 days.Another 75 mice were randomly divided into a control group（no radiation treatment）and radiation group（20 Gy radiation,and 25 Gy radiation treatment）,and the change of body weight of the mice was examined daily after radiation,and the mice were executed at 4 weeks after radiation to observe the change of liver organ ratios.The changes of serum aspartate aminotransferase（AST）,alanine aminotransferase（ALT）,and alkaline phosphatase（ALP）levels in the liver of mice were detected,and the liver tissues were examined by HE staining and Masson staining pathology after 36 weeks of radiation.Results: The mice in the 30 Gy and 35 Gy radiation groups showed high lethality;The mice in the 20 Gy and 25 Gy radiation groups showed a significant decrease in body weight（compared to the control group）.The serum levels of ALT（relative to the control group）were significantly increased in the 20 Gy radiation group,and the serum levels of AST and ALT（relative to the control group）were increased in the 25 Gy radiation group.No significant changes were observed in the liver of mice in the 20 Gy and 25 Gy radiation groups,but pathological tests showed that both the 20 Gy and 25 Gy prescription doses induced radiation-induced liver injury in the liver of mice.Conclusions: 30 Gy prescription dose and 35 Gy prescription dose are not suitable for constructing a precise model of radiation-induced liver injury in mice under a linear accelerator.20 Gy prescription dose and 25 Gy prescription dose both induce radiationinduced liver injury in mice.The mouse model of RILD constructed by the SBRT technique under linear accelerator is of great research significance to explore the disease of RILD. |
PDF Full Text Request