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Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges:...

Date post: 26-Mar-2015
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Page 1: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.
Page 2: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.
Page 3: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Ultraviolet Radiation (UVR)• Electromagnetic spectrum (2000 to

4000 nm)• Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm)• Little or no physiologic effect

– UV-B = Middle UV (2900 to 3200 nm)• Sunburn and age-related skin changes

– UV-C = Far UV (2000 to 2900 nm)• Bactericidal

Page 4: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.
Page 5: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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

Page 6: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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 is altered, which may result in cell death

Page 7: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Effects on Skin: Erythema

• Generalized response to UVR exposure– Reddening of skin

• Acute inflammatory reaction

• End results:– Erythema - sunburn– Pigmentation - tanning– Increased epidermal

thickness

Page 8: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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 or medications

are present on skin (or in

body)

Page 9: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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

Page 10: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Effects on Skin: Tanning

• Artificial Tanning - produce only UV-A

• Production of UV-A is largely unregulated

• Effects of long-term exposure to UV-A are unknown

Page 11: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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

Page 12: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Effects on Eyes

• UVR exposure causes acute inflammation called photokeratitis

• Delayed reaction, occurs within 6 - 24 hours

• Signs/Symptoms:– Conjunctivitis accompanied by erythema

of adjacent facial skin – Sensation of a foreign body on eye – Photophobia– Increased tear production– Spasm of the ocular muscles

Page 13: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Systemic Effects

• Photosynthesis of vitamin D – Following exposure to UVR in UV-B

range

• May be used to treat Ca++ and phosphorus disorders – Rickets and tetany

• Treatment of choice; however, is dietary supplementation

Page 14: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Ultraviolet Generators

• Carbon arc lamp• Xenon compact arc

lamp• Fluorescent

ultraviolet lamp (black light)

• Mercury arc lamp– Most commonly

used in sports medicine

Page 15: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Mercury Arc Lamp

• Mercury contained in a quartz envelope– Heavy metal in a liquid state

• At 8000°C, mercury atoms vaporize and become incandescent

• Emit ultraviolet, infrared, and visible light

Page 16: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Mercury Arc Lamp

• High-pressure lamp = “Hot” lamp

• UVR produced falls within UV-B range

• Mainly used to produce erythema

and accompanying photochemical

reactions

Page 17: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Mercury Arc Lamp

• Low-pressure = “Cold” lamp• Does not require warm-up or cool-

down • Used mainly for bactericidal effect

Page 18: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Mercury Arc Lamp

• Positioning– Apply cosine law and inverse square law

• Distance of lamp must be kept constant if intensity of treatments is to be equal

• Standardized at each clinic – Usually ranges between 24 - 40 inches

Page 19: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Techniques of Application

• Minimal Erythemal Dose (MED) – Exposure time needed to produce a faint

erythema of the skin 24 hours after exposure

• Question patient regarding photosensitizing drugs

Page 20: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Minimal Erythemal Dose

• Patient draped only exposing test site• Height of lamp adjusted to same level as

testng• Paper with five cutouts (1” square) 1” apart

placed over test site• Shutters are opened and cutouts exposed at

15-sec intervals

Page 21: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Minimal Erythemal Dose

• Visual inspection after 24 hours to determine MED– 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

Page 22: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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

Page 23: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

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 the use of ultraviolet

Page 24: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Indications

• Acne • Aseptic wounds• Folliculitis• Pityriasis rosea• Tinea capitum• Septic wounds• Sinusitis• Psoriasis

• Pressure sores• Osteomalacia• Diagnosis of skin

disorders• Increased vitamin

D production • Sterilization• Tanning• Hyperplasia

Page 25: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Contraindications

• Porphyrias• Pellagra• Lupus erythematosus• Sarcoidosis• Xeroderma

pigmentosum• Acute psoriasis• Acute eczema • Herpes simplex

• Renal and hepatic insufficiencies

• Diabetes• Hyperthyroidism• Generalized dermatitis• Advanced

arteriosclerosis• Active and progressive

pulmonary tuberculosis

Page 26: Ultraviolet Radiation (UVR) Electromagnetic spectrum (2000 to 4000 nm) Divided into three ranges: – UV-A = Near UV (3200 to 4000 nm) Little or no physiologic.

Thank you


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