ULTRAVIOLET RADIATIONSreeraj S R Ultraviolet radiation (UVR) covers a smallpart of electromagnetic spectrum lyingbetween the visible light and X-ray region.Sreeraj S R Types of UVRSreeraj S R Types of UVRUVA400 � 315 nm, near UVEffects: Erythema without pigmentationUVB315 � 280 nm, middle UVEffects: Erythema without pigmentation,formation of vit D, skin tanning (blister/burn)UVC280 � 100 nm, far UVKills bacteria, formation of vit. D, skin tanningSreeraj S R Production� Therapeutic UV usually produced by the passageof a current through an ionized vapour � oftenmercury vapour� at low pressure or high temperatures.Devices commonly used are either� air cooled (using air circulation with fan),or� water cooled (using a water jacket surroundingthe burner with continually circulating water).Sreeraj S R Mercury Vapor Lamp� produced by mercuryvapor lamp� which consists of aquartz burner tubecontaining traces ofargon gas and mercuryunder reducedpressure.� An electrode is insertedat each end of burnertube.Sreeraj S R Mercury Vapor Lamp� The current is applied to theelectrodes,� causes the formation of freemercury ions and electrons� When free electrons are beingaccelerated in the tube, manycollisions with neutral mercuryvapour atoms will occur:� By elastic collisions not

affecting the atom� By knocking an electron off theatom � ionization� By moving an electron to ahigher energy level � excitationSreeraj S R Fluorescent lamps� These are low-pressuremercury discharge tubes witha phosphor coating on inside.� The particular wavelengthsand the amount of eachemitted will depend on thecomposition of the phosphorused. (mixtures ofphosphates, borates, andsilicates.)� This gives a considerable UVAand UVB output but no UVC.Sreeraj S R Theraktin TunnelSreeraj S R Alpine Lamp� Medium � Pressure MercuryArc Lamp / high-altitude lamps� wavelength 253nm (shortwavelength) used in treatmentof generalised skin conditionsas acne and psoriasis.� Short UVR react with oxygen inthe air to produce a smallquantity of ozone (O3),� Ozone is toxic at highconcentrations so ventilationshould be adequate aroundthese lamps.Sreeraj S R Kromayer lamp� medium-pressure mercuryvapour lamps designed to beused in contact with thetissues, both on the skinsurface and in body cavities.� Water-cooled lamps,wavelength at 366nm giveboth UVA and UVB,� used for treating localisedlesions as pressure areas,ulcers, sheves and sinuses inopen areas.Sreeraj S R Physiological effects� Immediate/acute effects1. Erythema2. Pigmentation

3. Increased skin growth4. Vitamin D production5. Esophylactic effect6. Immunosuppressive effects7. Effects on eyeSreeraj S R Erythema� Erythema is reddeningof the skin as a result ofan inflammatoryreaction stimulated byultraviolet rays ?� release of histamine-likesubstance ?� dilatation of thecapillaries andarterioles andexudation of fluid intoskinSreeraj S R Pigmentation� Pigmentation or tanning of the skin followsthe erythema,� its amount varies with the intensity of theerythema.� It is due to the increased deposition of thepigment melanin formed in the basal cell layerof the skin by the melanoblasts, and migratesto the superficial layers of the epidermis.Sreeraj S R Desquamation� Is the casting off ofthe cells which havebeen destroyed bythe UVR,� Desquamation orpeeling isproportional to theintensity of theerythemaSreeraj S R Vitamin D production� UVB is able to convertsterols in the skin, such as7-dehydro-cholesterol tovitamin D� vitamin D is required toassist in the absorption ofcalcium and phosphorousfrom the intestine to bloodstream.� Suberythemal doses of UVBare adequate to promotevitamin D synthesisSreeraj S R

The Esophylactic effect� The resistance of the body to infection isincreased as a result of stimulation of reticulo-endothelial system ?� antibodies against bacteria and toxins.Sreeraj S R Immunosuppressive Effects:� UV destroys Langerhan�s cells and stimulatesthe proliferation of suppressor T cells.� (T cells are regulatory in that they inhibitantibody production)� This immunosuppressive effects maycontribute to the development of skin cancer.� In short, UV radiation induces a state ofrelative immunosuppression that preventstumor rejection.Sreeraj S R Effects on eye� Strong doses of UVB and C radiation to the eyes can leadto conjunctivitis and photokeratitis results in irritationof the eye, a feeling of grit in the eye, watering of theeye and aversion to light (photophobia)� In severe cases intense pain and spasm of the eyelid maybe present. This is also known as �snow blindness�� While UVB and C are absorbed in the cornea, UVA canpass through to be absorbed mainly in the lens of theeye.� The strong doses of UVA may lead to formation ofcataracts.Sreeraj S R Physiological effects� Long term/chronic effects1. Solar elastosis or aging2. CancerSreeraj S R Solar Elastosis & Ageing� Prolonged exposure of UVR lead to� premature ageing of the skin; this isespecially so in the fair-skinned.� decreased function of sebaceous and sweatglands� loss of elastic tissue� The skin becomes wrinkled, dry, and leathery.Sreeraj S R Cancer� skin cancers, basal cell and squamous cellcarcinomas.� Carcinogenesis is a danger, as these rays mayhave an effect on DNA and thus on cellreplication.� shorter ultraviolet waves should be avoidedand courses of treatment should not exceedfour weeks.Sreeraj S R

UVR dosage� Skin response to UVR depends upon:1. Quantity of UVR energy applied to the skin2. Biological responsiveness of skinSreeraj S R UVR dosage1. Quantity of UVR energy applied to the skinwhich depends upon:a) Output of the lampb) Distance between the lamp and the skinc) Angle at which radiation fall on the skind) Time for which radiations are applied onthe skinSreeraj S R UVR dosage2. Biological responsiveness of skin:Sreeraj S R Erythemal responseSreeraj S R Test Dose30 sec.60 sec.90 sec.A minimal dose (MED) is the length of the ultravioletexposure required to produce a mild erythema, whichappears within 6 to 8 hours and still just visible after 24hours.Sreeraj S R Test DoseTest applied11.00 amMondayMonday3 pm7 pm11 pm7 amTuesday11 amLook at the areas at the times shown and place a tick in the box if any redness is seen.If no redness is seen put a crossSreeraj S R Calculation of dosageE1 is determined from the skin test and the othererythemal dosages can be calculated as follows:������Suberythemal 75% of E1.E2 = 2.5 x E1.

E3 = 5 x E1.E4 = 10 x E1.Double E4 = 20 x E1.E4 & Double E4 are used on open wounds.Sreeraj S R Progression of UV dosageDoses can be progressed as follows:� Suberythemal � previous dose plus 12.5%.� E1 � previous dose plus 25%.� E2 � previous dose plus 50%.� E4 � previous dose plus 75%.Dosages used on open wounds are notprogressed because there is no epidermis tothicken.Sreeraj S R Alteration of the intensity with distance� To irradiate a smaller area the source is movednearer to the patient but the time of exposuremust be altered to maintain the sameintensity in accordance with the law of inversesquares.Now time = Old time x (new distance)2(Old distance)2Sreeraj S R Therapeutic uses� Psoriasis1.2.3.Goeckerman regimenIngram/Leeds regimenPhotochemotherapy�����������Acne VulgarisEczemaChronicinfection/woundVitiligoProtection forhypersensitive skinVitamin D deficiencyMild hypertensionPruritisPsychological benefitsNon infected woundsIntact skinSreeraj S R

Psoriasis� a skin condition, whichpresents localized plaquesin which the rate of cellturnover from the basallayer through to thesuperficial layer is too rapid.� The aim of ultravioletirradiation is to decreasethe rate of DNA synthesis inthe cells of the skin andthus slow down theirproliferation(immunosuppressive effectof UVR).Sreeraj S R PsoriasisGoeckerman Regimen:� This consists of coal tar applications 2 to 3 times aday with general (total body) UVB radiation givenonce a day as a suberythemal or E1 dose.Ingram or Leeds Regimen:� The patient has a coal tar bath before beingirradiated with a minimal erythema dose of UVB;� the psoriatic lesions are covered with dithranol.� Next day the dithranol is cleaned off and the processis repeated.Sreeraj S R PsoriasisPhoto chemotherapy :� Psoralen-type drug is given to the patient some 2 hourspreviously, to make him/her sensitive to UVA radiations,� This will produce an erythema at lower intensities thannormal.� The drug 8-methoxy-psoralen is used making the patienthighly reactive to UVA once it has been absorbed, for some 6� 8 hours.� As the peak of PUVA erythema occurs at 48 � 72 hours,treatment should be given twice a week until clearance.� This should be approximately 12 �18 exposures.Sreeraj S R Acne Vulgaris:� This is a chronicinflammatory conditionof the pilosebaceousunit especially affectingthe face, chest, andback.� Using UVR is aiming toproduce desquamationto open the blockedpores and hair follicles.� usually E2 are usedSreeraj S R Eczema:

� an inflammatory responsein the skin, with associatedoedema, itching withredness, scaling, vesicles,and exudation of serum onthe skin.� It may be caused by contactdermatitis, atopic eczema.� It is often these who canbenefit from mild ultraviolettreatment.�Sreeraj S R Infected Wound� treated with high doses of ultravioletradiation.� A Kromayer lamp is successful in inhibitingbacterial colony growth.� The doses given must be an E4.Sreeraj S R Non-Infected Wounds� the aim of ultraviolet radiation is to stimulatethe growth of granulation tissue and thusspeed up repair.� Can be used in surgical incisions, pressureareas, venous and arterial ulcers.� UVA, E3 dose is sufficient.Sreeraj S R Incipient pressure areas� UVR may be used toprevent pressure areas frombreaking down and� stimulate the growth ofepithelial cells and todestroy the surfacebacteria.� E1 dose progressed dailyusing the Kromayerlamp.� In areas such as the heels orthe elbows where the skin isthicker, an E2 may be used.Sreeraj S R Vitiligo� an autoimmune disease inwhich destruction ofmelanocytes in local areascauses white patches to appearon the skin.� Both UVA and B stimulatemelanocyte activity� UVA seems to provoke a darkerand long-lasting tan althoughthe protective effects do notseem to be so marked� UVB provokes more thickeningSreeraj S R

Protection for Hypersensitive Skin� Polymorphic light eruption is the commonestof photodermatoses� increased tolerance to sunlight can beachieved by a course of UVB� start with a very low dose and graduallyprogressing.Sreeraj S R Vitamin D Deficiency� Vitamin D3 is formed in skin by the action ofUVB and C on 7-dehydrocholesterol.� natural sunlight can also be curative forvitamin D deficiency diseasesSreeraj S R Mild Hypertension� The general (whole body) suberythemaldoses of UVB can significantly lower bloodpressure� it is believed to be due to calcium regulatinghormones associated with increased vitamin Dproduction.Sreeraj S R Pruritus� The intractable and serious itching that canoccur due to raised bile acid level in biliarycirrhosis or uraemia.� can successfully treated by suberythemalwhole-body UVB either alone or incombination with the drug cholestyramine.Sreeraj S R Psychological Benefit� patients expect to feel better and� the consequent tanning makes them lookbetter.Sreeraj S R Contraindications to UVR� Acute skin conditions � acute eczema, dermatitis, lupuserthematosis(auto-immune disease) and herpes simplex� an existing ultraviolet Erythema.� Skin damage due to ionizing radiations � deep X-raytherapy.� Photo allergy � allergic reaction to ultraviolet radiation.� Acute febrile illness � whole-body treatment should beavoided.� Recent skin grafts.Sreeraj S R Dangers� Shock: the machine should be earthed and the main power cordinsulation intact.� Eyes: it is important to protect the eyes of both patient andtherapist from scattered and reflected radiations. The patientshould wear goggles even when not facing the source of radiations.The physiotherapist should be aware of the cumulative effect of

UVR through the day.� Over dosage: to avoid long exposure to UVR, use an accurate timingdevice especially for periods over about 1 minute. Overlap of dosesmay lead to burn.� In case of an accidental overdose infrared radiation may be givento the area in an attempt to increase local circulation and therebydisperse the histamine-like substance that produces the erythema.� Sensitization: a number of drugs and some foods in few patientscan alter the effect of UVR and cause sensitivity.Sreeraj S R References1.2.3.4.5.6.Electrotherapy Explained by Low and ReedTextbook of Electrotherapy by Singh Jagmohanhttp://faculty.ksu.edu.sa/68417/RHS%20321/ULTRAVIOLET%20%20RADIATIONS%20(2).pdfhttp://www.aarogya.com/conditions-and-diseases/specialties/physiotherapy/4823-electrotherapy.html?start=2Ultraviolet Radiation by Sagar Naik. physio4allUltraviolet germicidal irradiation: current best practices by Stephen B.Martin, Jr. et al. ASHRAE Journal, August, 2008Sreeraj S R