If you solve that properly, this will really take off and do a lot of good.
Also, you're going to eventually need to take a very small cut of the donations to pay living expenses for your volunteers. 100% to the patient sounds great, but for my donation, I'd prefer to know that there is someone dedicated full-time to the cause and overseeing the process, and receiving a reasonable salary for it. Of course, be 100% transparent about those salaries as well.