Clinical Study of 2 Radiotherapy Techniques for Semi-Hepatic Alternating Radiotherapy on Diffuse Liver Metastasis in Patients with Breast Cancer oleh Jiangzhou Zhang MD, Shuheng Bai MD, Xingzhou Zhang MS, Yanli Yan MD, Haojing Kang MD, Guangzu Li MD, Zhaode Feng MD, Wen Ma MD, Hong Sun MD, Juan Ren MD, PhD