Pelvic insufficiency fractures (PIF) is a vital complication after radiotherapy for pelvic neoplasms. It often leads to intractable pain and limited activity and is likely to be misdiagnosed as bone metastases and improperly treated. MRI is a common method for the diagnosis and differential diagnosis of PIF. The optimal approach to prevent PIF is to correctly identify the high-risk population and provide drug intervention when necessary. The low bone density state serves as a pivotal predictor at the beginning of radiotherapy. Reasonable selection of irradiation dose in pelvic lymphatic drainage area and minimizing the dose of pelvic bone probably reduce the incidence of PIF after radiotherapy.

Pelvic neoplasm/radiation therapy; Pelvic insufficiency fractures; Sacral bone