What ships left US (Boston) late 1906?

Hello! I hope someone can help me finding Anna Person/Persdotter who left US and turned up back in Sweden in December 1906. She probably travelled from Boston late that year. Could have been another harbour though... Boston was the place she travelled to in 1893 - but we don't know where she stayed all the years between. We guess she lived in Chicago or Michigan...but she could have stayed elsewhere! Anna was born Dec 22 1867 in Persby, Sunne, Sweden. [:)]