Ultraviolet TherapyUltraviolet TherapyUltraviolet TherapyUltraviolet Therapy

Ultraviolet Radiation(UVR)

Ultraviolet Radiation(UVR)

• In electromagnetic spectrum UVR ranges from 2000 to 4000 Å

• Divided into three ranges: – UV-A- near UV- 3200 to 4000 Å

• Little or no physiologic effect

– UV-B- middle UV- 2900 to 3200 Å • Associated with sunburn and age-related skin

changes

– UV-C- far UV- 2000 to 2900 Å• Bactericidal

• In electromagnetic spectrum UVR ranges from 2000 to 4000 Å

• Divided into three ranges: – UV-A- near UV- 3200 to 4000 Å

• Little or no physiologic effect

– UV-B- middle UV- 2900 to 3200 Å • Associated with sunburn and age-related skin

changes

– UV-C- far UV- 2000 to 2900 Å• Bactericidal

Ultraviolet RadiationUltraviolet Radiation

• UVR apparatus most likely to be used would generate UVR in UV-B, UV-C or both ranges

• UVR is absorbed within first 1 to 2 mm of human skin

• Most of physiologic effects are superficial

• Used to treat various skin disorders

• UVR apparatus most likely to be used would generate UVR in UV-B, UV-C or both ranges

• UVR is absorbed within first 1 to 2 mm of human skin

• Most of physiologic effects are superficial

• Used to treat various skin disorders

Effect On CellsEffect On Cells

• Exposure of skin to UVR causes chemical excitation of cells which leads to physiologic changes within these cells

• Alteration of cell biochemistry and cellular metabolism which affects synthesis of DNA and RNA

• This leads to alterations in protein and enzyme production

• Exposure of skin to UVR causes chemical excitation of cells which leads to physiologic changes within these cells

• Alteration of cell biochemistry and cellular metabolism which affects synthesis of DNA and RNA

• This leads to alterations in protein and enzyme production

Short-Term Effects on SkinShort-Term Effects on Skin• Skin consists of two

layers– Epidermis

• Contains keratinocytes which produce keratin,- fibrous protective protein of skin

– Dermis • Papillary layer - rich blood

supply• Reticular layer - heavy

connective tissue containing fibroblasts, histocytes, and mast cells

• Skin consists of two layers– Epidermis

• Contains keratinocytes which produce keratin,- fibrous protective protein of skin

– Dermis • Papillary layer - rich blood

supply• Reticular layer - heavy

connective tissue containing fibroblasts, histocytes, and mast cells

ErythemaErythema

• Generalized response to UVR exposure culminates in development of an acute inflammatory reaction

• End results of active inflammation are – Erythema - reddening of skin associated

with sunburn– Pigmentation -tanning– Increased epidermal thickness

• Generalized response to UVR exposure culminates in development of an acute inflammatory reaction

• End results of active inflammation are – Erythema - reddening of skin associated

with sunburn– Pigmentation -tanning– Increased epidermal thickness

InflammationInflammation

• Inflammatory response characterized by local vasodilation and increased capillary permeability causing erythema

• Permits certain proteins to move from capillaries into dermis resulting in a change in osmotic pressure

• Water drawn into area and edema occurs

• Phagocytic cells eliminate dead cells

• Inflammatory response characterized by local vasodilation and increased capillary permeability causing erythema

• Permits certain proteins to move from capillaries into dermis resulting in a change in osmotic pressure

• Water drawn into area and edema occurs

• Phagocytic cells eliminate dead cells

PhotosensitizationPhotosensitization

• Over sensitization to UVR as a result of excitation of a chemical by UVR exposure

• Acute effects of UVR exposure can be exacerbated if certain chemicals or medications are present on skin or in body

• Over sensitization to UVR as a result of excitation of a chemical by UVR exposure

• Acute effects of UVR exposure can be exacerbated if certain chemicals or medications are present on skin or in body

TanningTanning• Increase of pigmentation in skin • Protective mechanism activated by UVR

exposure• Increase of melanin (pigment responsible

for darkening) within skin causes tan – Functions as a biologic filter of UVR

• By scattering radiation • By absorbing UVR• By dissipating absorbed energy as heat

• Increase of pigmentation in skin • Protective mechanism activated by UVR

exposure• Increase of melanin (pigment responsible

for darkening) within skin causes tan – Functions as a biologic filter of UVR

• By scattering radiation • By absorbing UVR• By dissipating absorbed energy as heat

TanningTanning

• Immediate tanning occurs following UVR exposure– Appears most often in darkly

pigmented individuals– Represents the darkening of

melanosomes already present in the skin

– Begins to fade 1 hour after exposure and is hardly noticeable 3 to 8 hours

• Immediate tanning occurs following UVR exposure– Appears most often in darkly

pigmented individuals– Represents the darkening of

melanosomes already present in the skin

– Begins to fade 1 hour after exposure and is hardly noticeable 3 to 8 hours

TanningTanning

• Delayed tanning results from formation of new pigment (melanin) through melanogenesis – Delayed tanning usually becomes

apparent 72 hours after UVR exposure

• Delayed tanning results from formation of new pigment (melanin) through melanogenesis – Delayed tanning usually becomes

apparent 72 hours after UVR exposure

Artificial Tanning DevicesArtificial Tanning Devices

• Manufacturers claim tanning beds produce only UVR in UV-A spectrum and are safe – Production of this type of UV-A generator

is largely unregulated – Effects of long-term exposure to UV-A

are unknown – Caution should be exercised before using

an artificial source to expose to UVR

• Manufacturers claim tanning beds produce only UVR in UV-A spectrum and are safe – Production of this type of UV-A generator

is largely unregulated – Effects of long-term exposure to UV-A

are unknown – Caution should be exercised before using

an artificial source to expose to UVR

Long-Term Effects on SkinLong-Term Effects on Skin

• Premature aging of the skin – Dryness, cracking, and a decrease in

elasticity of skin resulting from epidermal solar elastosis • Alteration in the skin's elastic fibers • Linked to UVR-induced DNA damage

• Premature aging of the skin – Dryness, cracking, and a decrease in

elasticity of skin resulting from epidermal solar elastosis • Alteration in the skin's elastic fibers • Linked to UVR-induced DNA damage

Long-Term Effects on SkinLong-Term Effects on Skin• Skin cancer

– Most common malignant tumor found in humans

– Damage to DNA suspected as cause – Major types of skin cancer

• Basal cell carcinoma( rarely metastasizes) • Squamous cell carcinoma (metastasizes in 5%) • Malignant melanoma (Usually metastasizes

– Rate of cure exceeds 95% with early detection

• Skin cancer – Most common malignant tumor found in

humans – Damage to DNA suspected as cause – Major types of skin cancer

• Basal cell carcinoma( rarely metastasizes) • Squamous cell carcinoma (metastasizes in 5%) • Malignant melanoma (Usually metastasizes

– Rate of cure exceeds 95% with early detection

SunscreensSunscreens

• Sunscreen’s effectiveness in absorbing sunburn inducing radiation is expressed as sun protection factor (SPF)

• SPF of 6 indicates you can be exposed to UVR six times longer than without a sunscreen before receiving a minimal erythemal dose

• Sunscreen’s effectiveness in absorbing sunburn inducing radiation is expressed as sun protection factor (SPF)

• SPF of 6 indicates you can be exposed to UVR six times longer than without a sunscreen before receiving a minimal erythemal dose

Effect On EyesEffect On Eyes• UVR exposure of the eyes causes an acute

inflammation called photokeratitis– Delayed reaction occurring within 6 to 24 hours– Conjunctivitis develops, accompanied by

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

• UVR exposure of the eyes causes an acute inflammation called photokeratitis– Delayed reaction occurring within 6 to 24 hours– Conjunctivitis develops, accompanied by

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

Systemic EffectsSystemic Effects

• Photosynthesis of vitamin D following irradiation of skin by UVR in UV-B range– UVR can be used as treatment for

disorders of calcium and phosphorus metabolism, such as rickets and tetany

– Treatment of choice for such problems is dietary supplementation

• Photosynthesis of vitamin D following irradiation of skin by UVR in UV-B range– UVR can be used as treatment for

disorders of calcium and phosphorus metabolism, such as rickets and tetany

– Treatment of choice for such problems is dietary supplementation

Ultraviolet GeneratorsUltraviolet Generators

• Carbon arc lamp

• Xenon compact arc lamp

• Fluorescent ultraviolet lamp (blacklight)

• Mercury arc lamp

• Carbon arc lamp

• Xenon compact arc lamp

• Fluorescent ultraviolet lamp (blacklight)

• Mercury arc lamp

Carbon Arc LampCarbon Arc Lamp

• Composed of two carbon electrodes • Two electrodes move slightly apart

causing current to arc across small gap • UVR is emitted between 3500 and 4000

Å • Electrodes gradually burn and must be

replaced – Burning is noisy and causes an unpleasant

odor

• Composed of two carbon electrodes • Two electrodes move slightly apart

causing current to arc across small gap • UVR is emitted between 3500 and 4000

Å • Electrodes gradually burn and must be

replaced – Burning is noisy and causes an unpleasant

odor

Xenon Compact Arc LampXenon Compact Arc Lamp

• Composed of compressed xenon gas enclosed in a vessel

• Electric arc passed through gas • Gas is heated to 6000° C • Emits infrared, visible, and UVR in

range of 3200 to 4000 Å

• Composed of compressed xenon gas enclosed in a vessel

• Electric arc passed through gas • Gas is heated to 6000° C • Emits infrared, visible, and UVR in

range of 3200 to 4000 Å

Fluorescent UV Lamp(Blacklight)

Fluorescent UV Lamp(Blacklight)

• Low-pressure mercury lamp • Tube of UV-transmitting glass coated

with phosphors • Phosphors are fluorescing

substances that absorb the UVR and then reemit it at a longer wavelength

• UVR emitted ranges from 3000 to 4000 Å

• Low-pressure mercury lamp • Tube of UV-transmitting glass coated

with phosphors • Phosphors are fluorescing

substances that absorb the UVR and then reemit it at a longer wavelength

• UVR emitted ranges from 3000 to 4000 Å

Mercury Arc LampMercury Arc Lamp

• Most likely kind of UVR lamp to be used • Either low-pressure or high-pressure

mercury arcs – Mercury contained in a quartz envelope– An electric arc passes through vaporizing

mercury– At 8000° C atoms become incandescent

and emit ultraviolet, infrared, and visible light

• Most likely kind of UVR lamp to be used • Either low-pressure or high-pressure

mercury arcs – Mercury contained in a quartz envelope– An electric arc passes through vaporizing

mercury– At 8000° C atoms become incandescent

and emit ultraviolet, infrared, and visible light

Mercury Arc LampMercury Arc Lamp

• High-pressure = Hot Quartz• Most of UVR produced falls within UV-

B range• Mainly used to produce erythema and

accompanying photochemical reactions

• High-pressure = Hot Quartz• Most of UVR produced falls within UV-

B range• Mainly used to produce erythema and

accompanying photochemical reactions

Mercury Arc LampMercury Arc Lamp

• Low-pressure = Cold quartz lamp– Temperature of the quartz envelope is about 60° C – UVR spectrum limited to 1849 Å and 2537 Å – Does not require a warm up or cool down period, and is

used mainly where bactericidal effect of UVR is desired

• Low-pressure = Cold quartz lamp– Temperature of the quartz envelope is about 60° C – UVR spectrum limited to 1849 Å and 2537 Å – Does not require a warm up or cool down period, and is

used mainly where bactericidal effect of UVR is desired

Techniques of ApplicationTechniques of Application

• Effectiveness of lamp assessed by determining skin sensitivity to UVR – Measured by the minimal erythemal dose

(MED) • Exposure time needed to produce a faint

erythema of the skin 24 hours after exposure• Question patient regarding photosensitizing

drugs

– Area of skin to be tested should have pigmentation similar to area to be treated

• Effectiveness of lamp assessed by determining skin sensitivity to UVR – Measured by the minimal erythemal dose

(MED) • Exposure time needed to produce a faint

erythema of the skin 24 hours after exposure• Question patient regarding photosensitizing

drugs

– Area of skin to be tested should have pigmentation similar to area to be treated

Measuring MEDMeasuring MED

• Patient is draped except for test site• Piece of paper with five cutouts 1” square

and 1”apart placed over the test site • Height of lamp from patient adjusted to

same level as for treatment• Shutters are opened and cutouts exposed at

15-sec intervals 15, 30 , 45, 60, and 75 secs.

• Patient is draped except for test site• Piece of paper with five cutouts 1” square

and 1”apart placed over the test site • Height of lamp from patient adjusted to

same level as for treatment• Shutters are opened and cutouts exposed at

15-sec intervals 15, 30 , 45, 60, and 75 secs.

Determining MEDDetermining MED Patient returns in 24 hours and a visual

inspection determines MED • Areas tested that reveal no erythema 24 hours

after testing have received a suberythemal dose• Areas showing erythema at 24 hours have

received a minimal erythemal dose. • Erythema still present at 48 hours = 1st degree

erythemal dose • Erythema persists from 48-72 hours = 2nd degree

erythemal dose • Erythema lasts past 72 hours= 3rd degree

erythemal dose

Patient returns in 24 hours and a visual inspection determines MED • Areas tested that reveal no erythema 24 hours

after testing have received a suberythemal dose• Areas showing erythema at 24 hours have

received a minimal erythemal dose. • Erythema still present at 48 hours = 1st degree

erythemal dose • Erythema persists from 48-72 hours = 2nd degree

erythemal dose • Erythema lasts past 72 hours= 3rd degree

erythemal dose

Determining MEDDetermining MED

• 1st-degree and 2nd-degree doses can be estimated – 1st-degree erythemal doses

approximately correspond to 2.5 times minimal erythemal dose

– 2nd-degree doses correspond to 5 times minimal erythemal dose

• 1st-degree and 2nd-degree doses can be estimated – 1st-degree erythemal doses

approximately correspond to 2.5 times minimal erythemal dose

– 2nd-degree doses correspond to 5 times minimal erythemal dose

Determining MEDDetermining MED

• Since human skin adapts to UVR exposure, MED will gradually increase with repeated treatments

• Necessary to gradually increase exposure time to achieve the same reaction

• Once determined it is increased 5 seconds per treatment

• Height of lamp remains constant

• Since human skin adapts to UVR exposure, MED will gradually increase with repeated treatments

• Necessary to gradually increase exposure time to achieve the same reaction

• Once determined it is increased 5 seconds per treatment

• Height of lamp remains constant

Positioning The LampPositioning The Lamp

• Apply cosine law and inverse square law

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

• Generally standardized at each clinic usually ranging from 24 to 40 inches

• Apply cosine law and inverse square law

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

• Generally standardized at each clinic usually ranging from 24 to 40 inches

Treatment TechniqueTreatment Technique

• Patient should be draped and wear eye goggles

• Consistency in positioning of lamp is critical– Must be the same as in MED test

• Clinician must also wear goggles

• Open lamp shutters and begin timing simultaneously

• Patient should be draped and wear eye goggles

• Consistency in positioning of lamp is critical– Must be the same as in MED test

• Clinician must also wear goggles

• Open lamp shutters and begin timing simultaneously

Clinical ApplicationsClinical Applications

• Most common use of UVR is in treatment of dermatologic conditions such as psoriasis and 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

• Most common use of UVR is in treatment of dermatologic conditions such as psoriasis and 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

Indications for Ultraviolet TherapyIndications for Ultraviolet Therapy

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

• 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

• Pressure sores• Osteomalacia• Diagnosis of skin

disorders• Increased vitamin

D production • Sterilization• Tanning• Hyperplasia

Contraindications for Ultraviolet Therapy

Contraindications for Ultraviolet Therapy

• Porphyrias• Pellagra• Lupus erythematosus• Sarcoidosis• Xeroderma

pigmentosum• Acute psoriasis• Acute eczema • Herpes simplex

• 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

• Renal and hepatic insufficiencies

• Diabetes• Hyperthyroidism• Generalized dermatitis• Advanced

arteriosclerosis• Active and progressive

pulmonary tuberculosis