Abstract: Tattooing is halachically prohibited. A true medical need supercedes this prohibition. Marking a location for radiation therapy may be such a need. However, halacha observant women may prefer the use of other techniques such as markers.
Discussion: In many cancer centers, proper alignment of the radiation field is achieved by tattooing the outline of the area to be irradiated with tiny dots . Tattooing poses a halachic problem stemming from Leviticus 19:28. According to most halachic authorities, this biblical prohibition applies to any mark that is caused by the use of both an instrument and color. There is a minority opinion that unless letters are formed there is only a rabbinic prohibition.
The halachic imperative to save lives permits tattooing if there is no other option, and there is no need for a patient to look for another, possibly less satisfactory, facility just to avoid tattooing. If tattooing is required, however, it is preferable for the procedure to be done by a non Jew. If this is not feasible and a Jew performs the tattooing, at the least the patient should not assist in the procedure but should remain passive.
Another option is to use markers. Most facilities find this less preferable because the markings tend to fade. However, since radiation therapy is generally performed daily, new marking can be reintroduced over the existing color. Problems may arise when there is a hiatus of a few days, or the color may fade when the woman showers. Even in this case, however, there is usually enough color remaining for the technician to reintroduce the markings.
As the ink is under the skin, a tattoo is not considered a barrier to ritual immersion. Marking is also not considered a barrier to immersion since it must be in place for an extended period, the patient wants (and needs) it to be there, and the ink is absorbed into the skin rather than adhering to its surface.
Implications for Patient Care: Due to halachic issues with tattooing, halacha observant women may prefer to use markers. In cases where the physician considers tattooing to be critical, the reasons should be conveyed to the patient's halachic advisor.
 DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, Seventh Edition. Philadelphia: Lippincott Williams and Wilkins, 2005:1440-41.
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