Ultraviolet Radiation Mohammed TA, Omar PhD, PT, PGDCR Dr.Taher_M@yahoo.com momarar@ksu.edu.sa

What’s the UV? Ultraviolet radiation is a portion of electromagnetic spectrum that is lies between X-ray and visible light. UV wavelength ranges from 100 to 400 nm .

Sources & Production of UV rays

Natural Source of UVR The natural source of UVR is the sun , which emits a broad spectrum of UV (UVA 98.7% , UVB, &UVC) both UVA & UVB reach the earth however the UVC is filtrated out by the ozone layers.

Artificial Source of UVR UVR produced artificially for therapeutic purpose by the passage of electrical current through an ionized vapor –often mercury. The therapeutic UVR are produced by: 1-Mercury vapour lamp which consists of a quartz burner tube evacuated from air and containing traces of argon gas and mercury under reduced pressure. 2- An electrode is inserted at each end of burner tube. 3- Electrical current is applied to the electrodes,

Types Artificial Source of UVR 2-Water cooled lamps (Kromayer lamp) Wavelength at 366nm (UVA+UVB) Used for localised lesions ( pressure areas, ulcers, ) 1-Air-cooled lamps: Wavelength 253nm (short wavelength) Used for acne and psoriasis.

Artificial Source of UVR 3-Fluorescent lamps (Theraktin lamp) Consists of a number of fluorescent tubes incorporated into a semicircular tunnel - The wavelength between 290 and 350 nm (UVA long) - Used in treating psoriasis affecting large areas. 4-Carbon arc lamps 5-Xenon compact lamps 6-Mercury lamps.

Classification of UV Bactericidal effect Sunburn & Cancer Dermis 100 to 280 nm Sunburn & Cancer Epidermis 280 to 315nm Aging of skin Dermis 315 to 400nm

Physiological Effects of UV

When radiation strikes the skin, part is reflected, part is absorbed and penetrates in various layers, (subcutaneous tissue, hair follicles, and sebaceous glands) , until the energy of the incident beam has been dissipated usually at 2mm depth.

The effects produced by the absorption of UVR are Primarily Local Effects, although some General Effects occur if the larger areas are treated with high doses

Local Effects of UV Erythema vasodilation Pigmentation or tanning of the skin Increased deposition of the pigment melanin DesquamationIs Casting off of the cells which have been destroyed by the UVR desquamation is proportional to the intensity of the erythema Growth of epithelial cells increased as a part of the repair process which follows the erythema Antibiotic effects include the destruction of viruses, bacteria, and other small organisms on the skin surface (effect of UVB).

1- Erythema Erythema is reddening of the skin as a result of an inflammatory reaction stimulated by ultraviolet rays→ release of Prostaglandins &Histamine-like substance→ dilatation of superficial dermal blood vessels, and exudation of fluid into skin.

Pigmentation or tanning of the skin follows the erythema, its amount varies with the intensity of the erythema. Pigmentation is due to the increased deposition of the melanin pigment formed in the basal cell layer of the skin by the melanoblasts, and migrates to the superficial layers of the epidermis. Immediate tanning; Appears most often in darkly pigmented individuals. Occurs immediately following UVR exposure. Immediate tanning represented the darkening of melanosomes already present in the skin. It begins to fad 1 hour after exposure and is hardly to noticeable 3-8 hours later Delayed tanning; Results form formation of new melanin pigment through the process of the melanogenesis. Melanogenesis occurs within the melanocytes of the basal layer of the epidermis. The end product of this process are melanosomes, new pigment granules. Delayed tanning usually become apparent 72 hours after UVR exposure. 14

General Effects of UV Formation of vitamin D Vitamin D is required to assist in the absorption of calcium and phosphorous from the intestine to blood stream

General Effects of UV 2-The esophylactic effect The resistance of the body to infection is enhanced after exposure to UVA . This is thought to be the results of stimulation of Reticular- endothelial system (the cell that ingest bacteria and produce antibodies against bacteria and toxins. 3- Variations in responses to UVR Depend on skin type, Degree of pigmentation Age of subject.

Long Term Effect of UV on the skin I- Ageing of the skin:- II- Skin cancer:- III-The effects on eyes Photokeratitis Conjunctivitis Cataract

Indications of UVR Diseases can be treated by ultraviolet phototherapy are:- Dermatological conditions as; Psoriasis, Acne Vitiligo Eczema, Herpes zoster, Alopecia, Dermatitis, Ringworm. Local ulcerations & wound ( infected or non-infected) Calcium and phosphorus diseases. i.e. osteomalacia.

Contraindications of UV Dermatological conditions; (Lupus erythematosus, Sarcoidosis, Acute psoriasis, Herpes simplex , Acute eczema, and generalized dermatitis). known photosensitivity, Photosensitive drugs , recent deep X-ray therapy. Pulmonary tuberculosis. Sever diabetes, Hyperthyroidism. Advanced arteriosclerosis. Pellagra.

Dangers and Precaution of UV 1-Shock is a danger for both patient and therapist. The machine should be earthed and the main power cord insulation intact. 2-Damage to the eye; The eyes of both therapist and patient must be protected by wear Goggles made of glass absorb all UVR and offer maximum protection. 3-Over dosage & Burn; There is a risk of producing an ultraviolet burn if care is not taken to prevent the overlap of doses 4-Sensitizing drugs; Number of drugs and some food in a few patients are known too sensitive patient to the effect of UVR.

Principle of Application UVR

Principle of Application of UVR To assess the individual patient's reaction to UVR a test dose (erythema dose or response) is required. The technique is very similar whether a Therakin tunnel, an air- cooled or Kromayer lamp is used. Only the distance and time are varying.

Test Dose (Erythema test) of UVR The patient should be placed in comfortable position and the area test must be cleaned and washed to remove grease usually flexor aspect of the forearm. The eye must be protected by wearing goggles either of patients and therapist. If not available closing the eye and wrapping with peace of cotton . A piece of typing paper with five cutouts 1-inche square and 1-inche apart is placed over the test site.

Test Dose (Erythema test) of UVR If necessary the lamp is warmed up with the protective shutter is closed; 1-The arc lamp requires warm up time of 5-10 minutes. 2-The fluorescent lamp requires warm up time of 1 minute. Once the lamp is warmed up, direct the beam toward the patient, with care being taken to adjust the height of the lamp from the patient to the same level as for treatment. With lamp is positioned directly on the test area the shutter is open and the cutouts covered at 15 seconds interval, so that the five portions of the skin will be exposed for 15, 30, 45, 60, 75 seconds.

Test Dosage (Erythema test) of UVR 30 15 60 75 45 The patient is asked to visually inspect the response of the areas in 24 hours and return to therapist who also visually inspects to determine the minimal erythema dose.

Blister Weeks or more < 2 DESQUAMATION PIGMENTATION DISAPPEARANCE APPEARANCE LATENT PERIOD DOSE Nil 24 No change SED <24 Pink 6-12 MED E1 Powdery Slight 48 Red 4-6 E2 In thin sheet Marked 72-96 Fiery-red& painful 2-4 E3 Blister Weeks or more Angry-red& < 2 E4

Calculation of Dosage The two significant units of measurement are: The length of time (seconds). The distance from the source of UVR to the patient (millimetres). E1 is determined from the skin test, the E2, E3 and E4 are calculated using the formulas: E2 = 2½ x E1 E3 = 5 x E1 E4 = 10 x E1

Calculation of Dosage EXAMPLE: If the E1 of the patient is 30s at a distance of 100mm, calculate the E3 at 100mm. E1 = 30s at 100mm E3 = 5 x E1 E3 = 5 x 30 = 150s at 100mm. 28

Progression of Dosage Because UV, when applied to normal skin causes reaction which thicken superficial layer of the skin, each dose must be progressed in a specific way to reach the same effective level of UV at each treatment. E1 is progressed by 25% of the preceding dose P1E1=25%E1. E2 is progressed by 50% of the preceding dose P1E2=50%E2. E3 is progressed by 75% of the preceding dose P1E3=75%E2

Examples of Progression of Dosage If E1 is 30s at 450mm, find the second progression (P2E1)? E1= 30s at 450mm P1E1 = E1 + 25% of E1 = 30 +30/4 = 30 + 7.5 =37.5s P2E1 = P1E1 + 25% of P1E1 = 37.5 +37.5/4 = 46.9s P2E1 = 47s at 450mm. 30

Selection of dosage The dosage level is selected according to the effects required for the treatment of the presenting condition. The following guide lines should be followed: 1- E1 or MED may be given to the total body area. 2- E2 may be only be given to up to 20% of the total body area. 3- E3 may be only given to up to 250cm2 of normal skin. 4- E4 may only be given to 25cm2 of the total body area. 31

Frequency of Treatment The frequency of treatment depends on the level of erythema produced. Successive doses of ultraviolet must never be given to normal skin while the erythema produced by preceding dose is still visible. The following guide lines should be followed when treating normal skin: E1 or MED may be given daily. E2 should be given every second day. E3 should be given every third or forth day (twice weekly). E4 may be only given once a week. N.B. when treating non-skin areas such as pressure areas or ulcers, all doses may be given daily as there is no erythema reaction produced. 32

Selection of UVR Lamp In general the lamp that provides a narrow band of radiation and uniform treatment of area with reasonable time should be selected. 1-The Arc lamp are generally small and emits radiation of consistent intensity, therefore used for treatment of smaller surface area e.g. hand. 2-The fluorescent lamp are long and emits higher radiation intensity in the middle than at the end.

Duration of treatment Every UV lamp should have its average E1 time and distance clearly marked as results of average reaction test on the numbers of peoples. Or as calculated form the test doses. Therefore the following guidelines can be used to calculate treatment time for different erythema level. E2 time = E1 time X2.5 E3 time = E1 time X 5 E4time =E1time X10

Duration of treatment If the E1 time for UV lamp is 1 minutes at 100cm, calculate the E2 time at 50cm. According to the inverse square law the half the distance require quarter the time E1 time at 50cm will equal 15 seconds. According to law of E2time = E1time X2.5 E2time = 15x2.5=37.5seconds