Based on analyses for the reason of the inaccuracy and the controlled status of the radiation -measurement equipment, this paper points out that the calibration of the radiation-measurement equipment has to be performed periodically during verification intervals, which is determined by the status of the equipment and stepwise weighting method.

Objective To analyze the efficacy,dose and complications of total body irradiation(TBI) for patients to receive hematopoietic stem cell transplantation(HSCT) in the treatment of leukemia and malignant lymphoma.Methods From May 2002 to February 2007,78 cases with leukemia or malignant lymphoma received the TBI before HSCT in our department.All the patients were irradiated with linear accelerator in 2 consecutive days at a total dose of 7 to 11 Gy,dose rate of 4.5 to 5.0 cGy/min,once per day.Among them,55 cases received traditional high-dose chemotherapy before radiotherapy,and the other 23 cases got TBI first followed by high-dose chemotherapy.Results All the cases used TBI prior to transplantation was successful,and no serious complication such as radiation pneumonitis was observed.Conclusion Our TBI regime is a safe and effective pretreatment for HSCT.TBI used before the large doses of the chemotherapy is recommended because it is proved to be effective,without affecting the survival rate,and of lesser TBI reaction and of lesser preparation work for irradiation to radiotherapist.More attention should be paid when the linear accelerator is employed for TBI.