It's an excellent question.
Therapeutic Touch can be done completely hands off and still be very effective, so someone who does not wish to be touched can have that preference honoured quite easily. I once had a client like this and we had many sessions together that were completely without touch. Many people find light stroking touch to be soothing and relaxing and if so it can facilitate their session. But it’s not necessary. When touch is used it is always with permission.
If a person is reluctant to lie on their back on the massage table, they could lie on their side or rest in a recliner or other chair. The most important thing is for the client to feel safe and comfortable. Establishing trust and a comfortable environment is the first step in a Therapeutic Touch session. Then the relaxation response can be elicited and the healing begin.