Possibility of OD on UVB narrowband
The second anecdote offered is an unpublished report of a psoriasis patient who was receiving narrow band UVB treatment. Sullivan suggests that since artificial, narrow band UVB treatment contains only that portion of the spectrum that is responsible for the synthesis of vitamin D and not other portions of the spectrum that degrade it, toxic amounts of vitamin D can be synthesized. The patient's vitamin D level rose to 127 ng/mL, which is theoretically toxic. Physicians are clearly obliged to measure their patients' vitamin D levels when administering a treatment that affects those levels.
From Masterjohn Dec 2006