Reiki is just another form of what used to be known as Spiritual Healing, but is now more commonly termed just 'healing'.
Registered healers do work with patients in the NHS, and healing is widely used in palliative care settings worldwide. Healing is an instinctive human ability as old as we are - it is in our ancient history and in our very essence.
Here is a link to evidence based research carried out in a hospital setting: www.thehealingtrust.org.uk/contact-us/research/
The main problem I have with Reiki is the very short training (just a couple of days) and the (to my mind) unnecessary use of symbols which add to the general sense of 'wooo'.
Training to be a registered healer takes place over several years, and requires a mentor and many case histories, as well as regular assessment at every stage of the four stages of training before you can become a 'registered healer' within the recognised body of the Healing Trust (formerly NFSH - National Federation of Spiritual Healers.)
Reiki uses the same energy which surrounds us all. It is a dramatic shortcut though, and there is no screening for suitability which worries me. Basically anyone could do it and could then go on to exploit the vulnerable.
I am a qualified complimentary therapist and became aware of clients' energies many years ago in my work. I embarked on the NFSH training years ago up to stage 3. If I continue at all I will complete the final stage 4 of the training required to become a registered healer. I won't be waving any symbols around, which seems to be what Reiki mainly is about.
If any Reiki Masters would like to put me straight about Reiki I'd be interested to hear.