Presentation on theme: "ULTRAVIOLET RADIATION (UVR) Radiation between the visible light & X-ray sections of the electromagnetic spectrum. (J. Ritter) VISIBLE LIGHTIRRUVRRADIO."— Presentation transcript:
ULTRAVIOLET RADIATION (UVR) Radiation between the visible light & X-ray sections of the electromagnetic spectrum. (J. Ritter) VISIBLE LIGHTIRRUVRRADIO f
NATURE OF UVR 1. 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) Other Names LongMediumShort BlacklightErythemalGermicidal Near Far
CATEGORIES OF UVR Near 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: SUN 5-10% of the sun’s energy is in the UVR range ( nm) UVA 6.3% of sunlight during summer; UVB 0.5% Both UVA & UVB can be involved in sunburn and skin diseases
II. ARTIFICIAL WAY Passage 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°
A.KROMAYER LAMP a.k.a. water-cooled lamps requires pre-heating of 5 minutes a 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 inside absorbs 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 lamps generally used for treatment of generalized skin conditions like Acne and Psoriasis Usually applied at a distance of cm
D. LOW PRESSURE MERCURY VAPOR DISCHARGE TUBES Components: a. Tube or envelope made of quartz or special glass to allow UVR to pass through b. Metal electrodes sealed in the ends of the tube c. Electric circuit to regulate electric current
PHYSIOLOGIC EFFECTS 1. Erythema or redding & tanning - only encountered when UVB (at 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 EFFECTS 3. 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 EFFECTS 5. Vitamin D production - UVB convert sterols in the skin (7- dehydrocholesterol) to vitamin D at nm 6. Destruction of bacteria -occurs by suppressing DNA and RNA synthesis at UVB at nm
PHYSIOLOGIC EFFECTS 7. Wound healing - using UVB at 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 diseases a.) Psoriasis treatment b.) 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. Vitiligo Tanning 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
CONTRAINDICATIONS 1. 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)
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 UVR 1. Eyes (conjunctivitis) 2. Overdose (too long exposure; too close to the lamp) 3. Previously protected skin 4. Electric shock 5. Burns 6. Chill 7. Sensitizers 8. Change of lamp
LEVELS OF UVR ERYTHEMA E1E2E3E4 Latent period 6-12 hrs6 hrs3 hrsLess than 24 hrs Appearan ce Mildly 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 days3-5 daysA week Skin edema None SomeBlisters
LEVELS OF UVR ERYTHEMA E1E2E3E4 Skin discomfort None Slight soreness; irritation Hot& painful Very painfu l Desquamatio n NonePowder y In thin sheets In thick sheets Relation to dose causing E
SELECTION OF DOSAGE LEVEL DOSAGEFREQUENCY 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 DOSAGE Using 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)