UV Radiation Flashcards
heliotherapy
therapeutic use of sunlight
actinotherapy
therapeutic use of light from lamp
UVA lengths
400-315 nm
UVB lengths
315-280 nm
UVC lengths
280-100 nm
biological effects depend on __
wavelength
__ and __ readily absorbed by air
UVR UVC
UV photons have __ energy than visible light
more
UV photos provoke __ in tissues causing ___
chemical reactions
damage
two source of UV production
vaporized mercury
fluorescent tubes
electrons flow through __ pressure mercury vapour (mercury lamp)
medium
Mercury vapour lamp
higher orbit and fall back to stable
__ pressure merc vapour (UV fluorscent lamp)
low
is UV florescent low or high merc vapour
low
UV fluorescent lamp
absorbed by phosphor coating which can re-emit visible light, UVA or UVB
Lamps produce wavelengths of __
mix of UVA, B C, visible light and infrared
do mercury lamps or fluorescent lamps warm up quicker
fluorescent need 1 minute
mercs need several minutes
UV lamps life span
output decreases w use
fluorescent max output at 100 hrs, merc at 20
500-1000 useful lamp life
Broadband UVB
280-320 nm
starting point
narrowband UVB
311-313 nm
more effective
how often should UV lamps be calibrated
twice/year
Uvr subjective
skin type history in the sun allergies/meds previous skin cancer liver disease
skin types
1-6 (always burns to always tans)
biological effects of UVR
on skin: erythema
Effects of UVR on skin
tanning desquamation epdiermal hyperplasia vitamin d production immunosupporession
melanogenesis
tanning
erythema
suburn
Effects of UVR on eyes
photokeratitis / conjunctivitis
cataract
UVB is ___ more potent than UVA
100-1000