At 6 weeks , the percentage of patients who achieved PASI 75 and PASI 90 was significantly greater for both regimens , bathing in geothermal seawater three times a week ( 68.1 % and 18.2 % , respectively ) and intensive treatment with geothermal seawater ( 73.1 % and 42.3 % , respectively ) than for NB-UVB monotherapy ( 16.7 % and 0 % , respectively ) ( P < 0.05 in all comparisons ) .