EFFECT OF FIELD SIZE ON ULTRAVIOLET MINIMAL ERYTHEMA DOSE

[摘要] The presence or absence of detectable erythema depends not only upon the quantity of light administered but also upon the size of the irradiated area. The amount of energy required to produce a perceptible erythema is greater for small radiation areas than for large. Therefore MED''s [minimal erythema dose] of different sized areas cannot be directly compared, especially when the field size is small. These relationships may be important in explaining discrepancies of minimal erythema doses reported by previous investigators who irradiated areas of small and widely variable size.