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)