Diffey B L
Phys Med Biol. 1981 Nov;26(6):1129-35. doi: 10.1088/0031-9155/26/6/011.
A theoretical analysis is presented of the biologically effective dose of the solar long wave ultraviolet radiation (UVA) received by patients who are being treated for psoriasis by oral psoralen photochemotherapy. It is shown that patients treated during the summer months in the UK may well receive a UV dose which is comparable with, or even in excess of, the dose of artificial UVA received in the treatment centre and consequently should be advised about limiting their exposure to sunlight on the treatment days. In the winter months in the UK the UVA intensity in sunlight is such that no unduly restrictive precaution need apply. However, at locations between about 40 degrees N and 40 degrees S, the solar UVA intensity in midwinter is still sufficiently high that unnecessary sunlight exposure on treatment days should be avoided.
对接受口服补骨脂素光化学疗法治疗银屑病的患者所接受的太阳长波紫外线辐射（UVA）的生物有效剂量进行了理论分析。结果表明，在英国夏季接受治疗的患者很可能接受的紫外线剂量与治疗中心接受的人工UVA剂量相当，甚至超过该剂量，因此应建议他们在治疗期间限制阳光照射。在英国冬季，阳光中的UVA强度使得无需采取过度严格的预防措施。然而，在北纬约40度至南纬40度之间的地区，冬至时太阳UVA强度仍然足够高，应避免在治疗日进行不必要的阳光照射。
