Yes. You can create your own symbol, with your own meaning behind it, and use it for the purpose you have created it for. My husband and I both have our own personal symbols we use as a signature of sorts. We also have our own symbols for various use that we have drawn in trance. These, in my opinion, have a much stronger link to our subconscious and conscious, and therefore our entire being accepts their influences far more readily than foreign symbols we may find in a book.
So you can put careful thought into your symbol, using numerology, alchemy, or runes (such as a bindrune), or you can just meditate on a particular energy or purpose, IE: protection and when you feel ready or an image appears in your mind, start drawing. Sometimes I draw them by feel, like my pen dances on the page as it feels right. Sometimes I see the symbol crystal clear in my mind and merely copy it onto paper.