Mammogram有效分辨率只有5-10mm.比大小不如超声波敏感

乳腺超声理论分辨率可以达到0.5mm，临床实际有效分辨大约3mm左右。

http://www.cancer.org/cancer/news/news/faster-tumor-growth-rate-proof-younger-women-need-yearly-mammograms

http://www.uptodate.com/contents/diagnostic-evaluation-of-women-with-suspected-breast-cancer

http://www.ncbi.nlm.nih.gov/pubmed/14652148