We have gone markless and tattoo less with the introduction of AlignRT.
I think your question Dustin is a sound one, however may I invite you to think about this slightly differently? Drawing markings and SSD’s on the patients skin I guess is fine if you then image and do not move your couch based on that image. Do you only look at images post radiation delivery daily?
If in fact you image and shift prior to delivery per fraction those marks begin to mean less and less. If you image and shift, do your therapists then re-enter the treatment room and re-draw the position of the fields post imaging? For me the anatomical position of the fields is key, the SGRT system is a tool to help to get you very close to that and then monitor during delivery of the radiation. You know you will be in the correct position as your imaging shows you this. You can also check coverage/swelling/weight loss from your daily cone beams. I think its more a protocol and process shift to drop your markings.
To make yourself happier could you audit the first fraction of say the last 30 patient XVi’s and table shifts post imaging? We also use a skin render from CT for a visual check on fraction 1. Very happy to talk through our process if this will help at all?