Multicatheter brachytherapy can be applied as a monotherapy or in combination with external beam radiotherapy as an adjuvant treatment for soft tissue sarcoma. Successful application of brachytherapy in the treatment of soft tissue sarcoma requires implementation of multiple imaging modalities during preoperative and postoperative planning. Preoperative imaging is essential in planning local therapy for soft tissue sarcoma in that it defines the proximity of the tumor to adjacent critical structures, predicts the likelihood of close or positive surgical margins, and aids in defining the target volume for a brachytherapy implant. In the postoperative setting, imaging is utilized to assess the accuracy of target volume coverage and integrity of the implant, as well as in three-dimensional treatment planning.