Abstract: Purpose: To measure the dosimeter of the peripheral organization of cancer patients who receive radiotherapy.Materials and Methods: To use TLD to measure thenormal peripheral organiztion and organs of 47 patients who receive radiotherapy. Results : The normal periphered organization receives 5.31 cGy dose if a breast cancer patient receives 250 cGy dose once.In the whole course, the normal peripheral organization receives 127.44 cGy while the treated part 6000 cGy. Conclusion : This report indicates doctors must accurately fix the position on target to improve the precision of theputting place and protect normal tissuse and imp important organs.When making atreatment plan, doctors must pay attention not only to the treatment effect, but also tothe method to reduce and prevent radiotherapy damage to the periphral organization andorgans to reduce new sicknesses.