Chapter 15_PET 4995(2)
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Transcript of Chapter 15_PET 4995(2)
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Ultraviolet Therapy
Jennifer L. Doherty-Restrepo, MS, ATC, LAT
Entry-Level Master Athletic TrainingEducation Program
PET 4995: Therapeutic Modalities
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Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to
4000 ) Divided into three ranges:
UV-A = Near UV (3200 to 4000 ) Little or no physiologic effect
UV-B = Middle UV (2900 to 3200 ) Sunburn and age-related skin changes
UV-C = Far UV (2000 to 2900 )
Bactericidal
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Ultraviolet Radiation Most likely to be used
UV-B or UV-C
UVR depth of penetration is 1 to 2 mm Physiologic effects are superficial Used to treat various skin disorders
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Effect on Cells UVR causes chemical excitation of cells Results in alteration of cell biochemistry
and cellular metabolism Affects synthesis of DNA and RNA
Protein and enzyme production isaltered, which may result in cell death
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Effects on Skin Epidermis
Keratinocytes, whichprovide fibrous protective
protein of skin Dermis
Papillary layer - rich bloodsupply
Reticular layer - heavyconnective tissue containingfibroblasts, histocytes, andmast cells
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Effects on Skin: Erythema Generalized response to UVR exposure
Reddening of skin
Acute inflammatory reaction End results:
Erythema- sunburn Pigmentation - tanning Increased epidermal thickness
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Effects on Skin:
Photosensitization Process in which a person becomes
overly sensitive to UVR Acute effects of UVR exposure may be
exacerbated if certain chemicals ormedications are present on skin (or in
body)
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Effects on Skin: Tanning Increase of pigmentation
Protective mechanism activated by UVR exposure
Increase of melanin Pigment responsible for darkening skin
Melanin functions as a biologic filter of
UVR By scattering radiation By absorbing UVR By dissipating absorbed energy as heat
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Effects on Skin: Tanning Artificial Tanning - manufacturers claim
tanning beds produce only UV-A Production of UV-A is largely
unregulated Effects of long-term exposure to UV-A
are unknown
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Effects on Skin: Long-term Premature aging of the skin Dryness, cracking, and decreased elasticity
Linked to UVR-induced DNA damage Skin cancer
Most common malignant tumor found in humans Basal cell carcinoma (rarely metastasizes) Squamous cell carcinoma (metastasizes in 5%) Malignant melanoma (usually metastasizes)
Damage to DNA suspected as cause Rate of cure exceeds 95% with early detection
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Effects on Eyes UVR exposure causes acute inflammation
called photokeratitis Delayed reaction, occurs within 6 - 24 hours Signs/Symptoms:
Conjunctivitis accompanied by erythema ofadjacent facial skin
Sensation of a foreign body on eye
Photophobia Increased tear production Spasm of the ocular muscles
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Systemic Effects Photosynthesis of vitamin D
Following exposure to UVR in UV-B range
May be used to treat Ca++ andphosphorus disorders Rickets and tetany
Treatment of choice; however, is dietarysupplementation
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Ultraviolet Generators Carbon arc lamp
Xenon compact arc lamp
Fluorescent ultraviolet lamp (black light)
Mercury arc lamp
Most commonly used in sports medicine
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Mercury Arc Lamp Mercury contained in a quartz envelope
Heavy metal in a liquid state
At 8000C, mercury atoms vaporize andbecome incandescent
Emit ultraviolet, infrared, and visible
light
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Mercury Arc Lamp High-pressure lamp = Hot lamp UVR produced falls within UV-B range Mainly used to produce erythema and
accompanying photochemical reactions
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Mercury Arc Lamp
Low-pressure = Cold lamp UVR between 1849 - 2537 Does not require warm-up or cool-down Used mainly for bactericidal effect
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Mercury Arc Lamp
Positioning Apply cosine law and inverse square law
Distance of lamp must be kept constantif intensity of treatments is to be equal
Standardized at each clinic Usually ranges between 24 - 40 inches
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Techniques of Application
Minimal Erythemal Dose (MED) Exposure time needed to produce a faint
erythema of the skin 24 hours afterexposure
Question patient regarding
photosensitizing drugs
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Minimal Erythemal Dose
Patient draped only exposing test site
Height of lamp adjusted to same level as Tx Paper with five cutouts (1 square) 1 apartplaced over test site
Shutters are opened and cutouts exposed at
15-sec intervals
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Minimal Erythemal Dose
Visual inspection after 24 hours to determineMED No erythema = suberythemal dose
Erythema still present at 48 hours 1st degree erythemal dose (2.5 times MED)
Erythema persists from 48-72 hours
2nd degree erythemal dose (5 times MED) Erythema lasting past 72 hours
3rd degree erythemal dose
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Minimal Erythemal Dose
Skin adapts to UVR exposure,therefore, MED will gradually increase
with repeated treatments Must gradually increase exposure time
to achieve the same reaction Increased by 5 seconds per treatment
Height of lamp remains constant
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Clinical Applications
Dermatologic conditions Psoriasis, acne, and hard to cure infectious
skin conditions such as pressure sores
Development of oral and topical
medications has greatly reduced theuse of ultraviolet
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Indications
Acne Aseptic wounds
Folliculitis Pityriasis rosea Tinea capitum Septic wounds Sinusitis Psoriasis
Pressure sores Osteomalacia
Diagnosis of skindisorders Increased vitamin D
production Sterilization Tanning Hyperplasia
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Contraindications
Porphyrias Pellagra
Lupus erythematosus Sarcoidosis Xeroderma
pigmentosum
Acute psoriasis Acute eczema Herpes simplex
Renal and hepaticinsufficiencies
Diabetes Hyperthyroidism Generalized dermatitis Advanced
arteriosclerosis Active and progressive
pulmonary tuberculosis