Consenting subjects will receive a semi-permanent tattoo in place of the standard of care permanent tattoo for radiation marking at the time of the radiation planning scan. Subjects will be monitored to ensure alignment is the same with the semi-permanent tattoo as the current standard of care. Subjects will be monitored to ensure there are no skin reactions or other side effects. Subjects will be followed for 15 months and will send pictures to the treatment team to ensure that the tattoo fades away within 12 months as expected.

Over 3 million patients are treated each year with radiation therapy, with most of these patients receiving permanent tattoos for treatment alignment. The purpose of these tattoos is to ensure accurate initial patient position prior to treatment. In the case where further on-board imaging such as x-ray or cone-beam CT is used, the radiation tattoos help minimize large shifts which increase treatment time and radiation exposure as further imaging may be required. The tattoos are simple and effective, but also permanent. These permanent tattoos serve as a daily reminder of prior radiation therapy in cancer survivors which may have a negative psychological impact on the patients quality of life. Due to this, many patients will seek laser tattoo removal after completing radiation therapy. There have been attempts at non-permanent tattoo options such as henna as well as omitting tattoos altogether using surface imaging. Unfortunately, henna and other temporary tattoos start to fade quickly and do not last the 6-8 weeks required for longer radiation courses. This means that the tattoos must be reapplied over the course of treatment which can introduce inaccuracies as well as prolongs the treatment time.

A novel semi-permanent ink has been developed and recently released which begins to fade after 6 months and disappears after about 1 year. This is the first ink of its kind and is delivered using a needle into the dermis just like a permanent tattoo, however it is able to be resorbed by the body after approximately 1 year. While the original purpose is for cosmetic tattoos it has a possible application in medical tattoos for radiation therapy.

It is the goal of this study to show that the semi-permanent ink is safe, allows for accurate alignment of the patient prior to treatment, lasts long enough for a full treatment course, and fades over time. The goal in subsequent studies is to improve patient quality of life by decreasing the negative psychological impact of having permanent tattoos following radiation therapy.

Inclusion Criteria:

• Patients requiring medical tattoo for treatment alignment.
• Patient being treated with some form of image guidance including kV, MV, or cone-beam CT.
• Age ≥ 18.
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2.
• Patients will engage in the informed consent process and provide study-specific informed consent prior to study entry and must be willing to have photos taken of their tattoos through the treatment and follow-up process and may be required to take pictures of their own tattoo to submit to the research team.
• Patient able to send picture of tattoo via secure messaging.

Exclusion Criteria:

• Known allergies or hypersensitivity to tattoo ink.
• Personal or religious objection to medical tattooing.
• Autoimmune or skin disorders which may be worsened by medical tattooing.
• Inability to complete the required forms; however, verbal completion is adequate if recorded on the consent documents.