What sort of radiation treatment is best for treating leiomyosarcomas?

Standard radiation. The size and grade of this tumor and extent of resection is all very important to be able to answer this. Surgery is the most important in treatment. If the patient needs radiation depending on initial size and location, radiation after surgery is best performed with imrt based standard daily radiation is likely the best method. However the planning process may be done in other successful ways.
Like real estate.. It's location, (not uterus).. Soft part sarcomas (as opposed to osteo- and chondro-) are un-common, need resection with a clear margin of healthy tissue, but still tend to recur locally (depending on size and grade) - thus XRT and distally- thus chemo, most commonly to lungs. Doses of 50-60gy are used, the technical issues depend on location. Extremities are easier to deal with than truncal.