ultraviolet radiation (uvr) radiation between the visible light & x-ray sections of the...

ULTRAVIOLET RADIATION (UVR)

Radiation between the visible light & X-ray sections of the electromagnetic spectrum. (J. Ritter)

VISIBLE LIGHTIRR UVRRADIO f

NATURE OF UVR1. Strongly absorbed in air (*short-

wavelength UVR)2. Behave like visible radiation in

terms of properties (reflection, refraction, transmission and absorption)

3. Transmit more energy, thus, producing more chemical changes not just simply heat

CATEGORIES OF UVR UVA UVB UVC

Wavelength(nm)

320-400 290-320 200-290

315-400 280-315 100-280

Other Names

Long Medium Short

Blacklight Erythemal Germicidal

Near Near Far

CATEGORIES OF UVRNear UVR- nearer the visible light spectrum but are longer in wavelength

*Longer wavelength are more beneficial (BIOTIC)

Shorter wavelength are ABIOTIC

PRODUCTIONS OF UVR

I. NATURAL WAY: SUN

II. ARTIFICIAL WAY

I. NATURAL WAY: SUN5-10% of the sun’s energy is in the UVR range (180-400 nm)

UVA 6.3% of sunlight during summer; UVB 0.5%

Both UVA & UVB can be involved in sunburn and skin diseases

II. ARTIFICIAL WAYPassage of electric current thru gas (vaporized

mercury)

Collision with the electrons flowing between the lamp’s electrodes

Mercury atoms become excited

Excited electrons return to particular electronic states in the mercury atom

Release some of the energy they have absorbed

RADIATION

II. ARTIFICIAL WAY

UVR can be produced if the temperature is high enough and pressure is low

UVR= T° + P°

ARTIFICIAL UVR APPARATUS John Low Wadsworth1. Kromayer lamp 1. Water-cooled lamp

(Kromayer lamp)2. Fluorescent lamp 2. Fluorescent lamp

3. Medium pressure mercury arc lamp (Alpine Sunlamp)

3. Air-cooled lamp (Alpine Sunlamp)

4. Low pressure mercury vapor discharge tubes

A. KROMAYER LAMPa.k.a. water-cooled lampsrequires pre-heating of 5 minutesa medium pressure mercury vapor designed to be used in contact with the tissue (i.e. treatment of localized pressure areas and ulcers).

A. KROMAYER LAMP

wavelengths of the rays produced are concentrated at 366 nm but a wide range of both UVA & UVB are produced.

B. FLUORESCENT LAMPS

low-pressure mercury discharge tubes with a phosphor coating on the insideabsorbs short UVR which causes excitation of the phosphor atoms and remission at a longer wavelength

B. FLUORESCENT LAMPS

gives considerable UVA & UVB output; NO UVC

more commonly used for Psoriasis affecting large body areas

C. ALPINE SUN LAMP

a.k.a air-cooled lampsgenerally used for treatment of generalized skin conditions like Acne and PsoriasisUsually applied at a distance of 45-50 cm

D. LOW PRESSURE MERCURY VAPOR DISCHARGE TUBES

Components:a. Tube or envelope made of quartz or special glass to allow UVR to pass throughb. Metal electrodes sealed in the ends of the tubec. Electric circuit to regulate electric current

PHYSIOLOGIC EFFECTS

1. Erythema or redding & tanning- only encountered when UVB (at

250-297 nm) treatment is used.

Minimal Erythemal Dose = smallest UVR dose to result in erythema that is just detectable by eye between 8-24 hrs after exposure

PHYSIOLOGIC EFFECTS

2. Pigmentation- results from formation of melanin

in deep regions of the skin & migration of melanin noticeable about 2 days after exposure

- UVB at 300 nm

PHYSIOLOGIC EFFECTS3. Hyperplasia- occurs at 72 hrs using UVB

4. Increase skin growth- increase keratinocyte cell

turnover so that skin grows more rapidly for a time leading to shedding of most superficial cells at an earlier stage

PHYSIOLOGIC EFFECTS5. Vitamin D production- UVB convert sterols in the skin

(7-dehydrocholesterol) to vitamin D at 280-300 nm

6. Destruction of bacteria-occurs by suppressing DNA and

RNA synthesis at UVB at 250-270 nm

PHYSIOLOGIC EFFECTS7. Wound healing- using UVB at 260-280 nm

8. Increase production of RBC

9. Stimulation of steroid metabolism- UVR promotes vasomotor responses

causing antirachitic effect

PHYSIOLOGIC EFFECTS

10. Immunosuppressive effects

- UVB destroys Langerhans cells & stimulate proliferation of suppressor T cells

PHYSIOLOGIC EFFECTS

11. Conjunctivitis / photokeratitis / cataract

- conjunctivitis occur at UVB with 270 nm

- cataracts at UVA since it can pass thru the eye’s lens

PHYSIOLOGIC EFFECTS

12. Premature aging of the skin (dry, wrinkled, decreased function of sebaceous and sweat glands)

13. Skin cancers

14. Psychological effects

INDICATIONS OF UVR

1. Skin diseasesa.) Psoriasis treatmentb.) Acne vulgaris treatment

To accelerate skin growth, help control infection, sterilize skin surface temporarily

INDICATIONS OF UVR

2. Healing of wounds (venus ulcers & pressure sores)

To increase rate of skin growth and to provide antibiotic effect

INDICATIONS OF UVR

3. VitiligoTanning and thickening of the

skin

4. Protection of hypersensitive skin

INDICATIONS OF UVR

5. Alopecia

6. Treatment of vitamin D deficiency

INDICATIONS OF UVR

7. Pruritus due to biliary cirrhosis or uremia

8. Jaundice for newborn babies

CONTRAINDICATIONS1. Acute skin conditions (acute

eczema, dermatitis)

2. Skin damage due to ionizing radiations like deep X-ray therapy

CONTRAINDICATIONS

3. Systemic lupus erythematosus can be triggered or exacerbated

4. Photoallergy / photosensitivity (albinism will not tolerate UVR)

CONTRAINDICATIONS

5. Porphyrias (rare metabolic disorder)

6. Pellagra (dermititis due to severe niacin deficiency)

CONTRAINDICATIONS

7. Acute febrile illness (pulmonary tuberculosis, severe cardiac involvement, acute diabetes mellitus)

8. Recent skin graft

PRECAUTIONS

Patients with:

a.) little pigmentation, often seen in blondes and redheads.

b.) conditions like syphilis, alcoholism, cardiac or renal disease, acute psoriasis, acute eczema, elderly and infants.

PRECAUTIONS

c.) Ingested certain food like strawberries, eggs or shellfish before treatment.

d.) Taking any of the ff: birth control, pills, tetracycline, diuretics and insulin.

e.) Recent superficial heat treatment before UVR radiation.

DANGERS OF USING UVR1. Eyes (conjunctivitis)2. Overdose (too long exposure; too close

to the lamp)3. Previously protected skin4. Electric shock5. Burns6. Chill7. Sensitizers8. Change of lamp

LEVELS OF UVR ERYTHEMAE1 E2 E3 E4

Latent period

6-12 hrs

6 hrs 3 hrs Less than 24

hrsAppeara

nceMildly pink

Definite pink-red; blanches

on pressure

Very red;does

not blanches

on pressure

Angry red

Approx. duration

of erythema

Less than

24 hrs

2 days 3-5 days A week

Skin edema None None Some Blisters

LEVELS OF UVR ERYTHEMAE1 E2 E3 E4

Skin discomfort

None Slight soreness

; irritation

Hot& painful

Very painfu

l

Desquamation

None Powdery

In thin sheets

In thick

sheetsRelation to

dose causing E1

1 2.5 5 10

SELECTION OF DOSAGE LEVELDOSAGE FREQUENCY

1. E1 or Minimal Erythemal Dose may be given to total body area

Given daily

2. E2 up to 20% of total body area

Every second day

3. E3 up to 250 square cm of normal skin

Every third or fourth day

4. E4 up to 25 square cm of normal skin

Once a week or every forth night

CALCULATION OF UVR DOSAGE

Basis: determined by performing skin test to get MED or E1

Two units of measurements to consider:a.) length of time (seconds)b.) distance from the lamp (mm)

CALCULATION OF UVR DOSAGE

Levels of dosage intensity

a.) E1= determined by the skin test

b.) E2= 2.5 x E1

c.) E3= 5 x E1

d.) E4= 10 x E1

If the E1 of the patient is 50 s at a distance of 200 mm, find E3 at 200 mm.

CALCULATION OF UVR DOSAGE

Progression of dosage:a.) E1 is progressed by 25% of the

preceding dose

b.) E2 is progressed by 50% of the preceding dose

c.) E3 is progressed by 75% of the preceding dose

If E1 is 30 s at 200 mm, find the second progression (P2E1).

CALCULATION OF UVR DOSAGE

Alteration of intensity with distance-guided by Law of Inverse Square which states that as the distance between the source and the patient increases, the intensity decreases in proportion to the square of the distance.

Formula: I = 1/ d2

nt= ot x nd2 od2

CALCULATION OF UVR DOSAGE

Using Kromayer lamp:-use the levels of dosage for intensity since the distance is always at 25 mm.

Using air-cooled lamps:-distance is from the burner of the lamp to the patient and follow the Inverse square law formula.

Using the kromayer, if the E1 of the patient is 2 s I/C, find the E1 at 100 mm.

Using the air cooled lamp, if the E1 at 400 mm is 30 s, find the E1 at 200 mm.

CALCULATION OF UVR DOSAGEUsing an applicator:

1.) Compute for coefficient of the applicator:

*Length of applicator in mm divided by 25

2.) Compute for applicator dose:

*in-contact dose (secs at mm) x coefficient of applicator (in mm)