I have decided to use soap nuts as my post chemo shampoo. I have used them before and found it to be really good as they are a natural product with no chemicals or additives.
I have used them in a little bag to do my washing and also concocted a brew to use as shampoo and have found it really nice.
Google/Wikki it to find out stuff about them.
I will let you know once I have lost my hair and it begins to grow back as to how I get on 
Lisa J