UVA Radiation UVA was once thought to have a minor effect on skin damage, but now studies are showing that UVA is a major contributor to skin damage. UVA penetrates deeper into the skin and works more efficiently. The intensity of UVA radiation is more constant than UVB without the variations during the day and throughout the year. UVA is also not filtered by glass. UVB Radiation UVB affects the outer layer of skin, the epidermis, primary agent responsible for sunburns. most intense between the hours of 10:00 am and 2:00 pm when the sunlight is brightest. more intense in the summer months accounting for 70% of a person's yearly UVB dose. UVB does not penetrate glass. Most important in formation of AK 290-320 Damaging Effects of UVA and UVB Both UVA and UVB radiation can cause skin damage including wrinkles, lowered immunity against infection, aging skin disorders, and cancer. possible mechanisms for UV skin damage are collagen breakdown, the formation of free radicals, interfering with DNA repair, and inhibiting the immune system.
Phototherapy Certain types of electromagnetic radiation can be used to treat some skin disorders. Blue light acne treatment UVB therapy Narrowband UVB therapy UVA1 therapy Targeted phototherapy Home phototherapy Excimer 308 nm laser treatment Photochemotherapy (PUVA) Photodynamic therapy (PDT) including Metvix PDT for skin cancers
Blue light acne treatment Blue light acne treatment is a non-invasive procedure that uses light in the blue wavelength range of 405-420 nm to kill the Propionobacterium acnes or P. acnes bacteria in skin. This photodynamic therapy is FDA-approved for the treatment of moderate acne vulgaris or acne vulgaris that has not responded to other acne therapies.
How does it work? The bacteria in acne release porphyrins. These are naturally occurring substances in the body, arising from the breakdown of haemoglobin in red blood cells. When porphyrins absorb light of certain wavelengths, free radical damage is produced, and this destroys the bacteria. Blue light acne treatment uses a narrow-band, high-intensity blue light source that is readily absorbed by porphyrins released by the bacteria causing acne. Former light therapies used UV light (usually UVB ), which can be damaging to skin. Hence UV light is no longer used to treat acne and blue light devices currently available for use do not contain ultraviolet (UV) light. Blue light acne treatment can be used alone or in conjunction with a photosensitizing agent such as topical aminolevulinic acid (ALA) hydrochloride solution (Levulan® and Kerastick®). Pre-treatment with the photosensitiser appears to offer additional reduction of lesions and pustules but will cause a crusting reaction for a few days.
What does the procedure involve? Blue light acne treatment is administered via a blue light delivery system. The procedure simply involves a patient sitting in front of a blue light lamp for about 15 minutes. Generally 2 sessions per week over a 4-week period is all that is required. Pre-treatment with ALA requires the topical application of ALA 30 minutes prior to sitting in front of the blue light lamp for about 8 minutes. Treatments are usually spaced at 2-week intervals. The number of treatments depends on the severity of acne and improvements seen. Blue light acne treatment is available from a dermatologist and the procedure performed in their rooms. Although blue light delivery systems can be purchased and self-administered at home, a dermatologist should oversee its use.
How effective is it? Several small studies have shown that blue light acne treatment appears to improve acne vulgaris with a reduction in inflammation and the number of pustules and papules in some individuals. In one study, nodulocystic acne lesions worsened when treated with blue light. Further large, controlled studies are needed to prove their efficacy and long-term effects. Other treatments for acne may be more suitable in the individual case.
UVB Phototherapy UVB phototherapy refers to irradiation with short wave ultraviolet radiation. To treat the whole body, the patient, undressed, stands in a specially designed cabinet containing fluorescent light tubes. Traditionally, broadband UVB has been used, but increasingly, narrowband UVB phototherapy (311nm) is provided. Phototherapy cabinet Whole body unit Control panel of Daavlin combined UVB/PUVA unit Increasing doses of UVB are given each exposure (three to five times weekly), aiming to turn the skin slightly pink. Sometimes uncomfortable sunburn will occur, at its worst about 8 hours after treatment. This fades over the next few days and should be treated with frequent and liberal emollients . The effect of UVB is similar to the sun. Excessive exposure contributes to aging skin and to the risk of skin cancer.
Have you lived or worked abroad
Blistering due to UVB
Esp Caucasian south African or Australian patients.
Transplant patients Organ transplant recipients develop cutaneous malignancies at a rate up to 250 times that of the general population.[
Esp if bald
Individual with 8 AK’s has risk of 10% of developing SCC. AK are atypical keratinocytes at the basal cell layer of the epidermis. On advanced lesions may extend across the entire epidermis. Always solar elastosis
AK or solar keratosis usually present as 0.5cm to 1cm scaly rough crusted, reddish-brown, or skin coloured lesions. Sand paper texture GPs major role in identifying and treating Aks Impossible to tell which will progress to SCC and which will not, so treatment recommended for all AK.
Increasing age shows increasing prevalence with 50% of men over 75 having AK Numbers of cases increasing also due to increased identification but increasing incidence
Present as non healing scabby area. Patients often not bothered by them as not bleeding or painful
Important to stretch the skin to see if any induration. Can be difficult to differentiate between actinic keratosis and superficial BCC
Bowen’s disease Persistent indurated discoid scaly area commonly on lower legs. Bowen’s disease or carcinoma in situ ie localised neoplastic degneration limited to the epidermis 3-5% risk of Bowen’s transforming to SCC Treatment for Bowen’s depends on size and location of tumour eg excision, topical trmt verses PDT
Non urgent referral
Lesions with rapid onset, hardened tissue surface, inflammed surface Atypical features eg does not respond, critical site, immunosupressed and lesion >1cm then refer
Indication significantly palpable but not indurated for single or multiple lesions Efudix is 5 fluorouracil is thymine analogue antimetabolite. Discovered when oncology patient treated with systemic 5FU noted inflammation then clearance of Aks. Used to treat Bowen’s disease, Aks and superficial BCC. Must warn patients to expect inflammation (indeed prob not working unless inflammatory response is generated). May become sore, red weep and ooze. This is normal. Apply to abnormal skin and a rim of normal skin. Use cotton bud or gloves to apply. Wash hands after. Use with caution areas around nose or eyes (esp not allowing cream to accumulate in creases)
Clean skin with normal saline and remove scales and crusts Roughen skin surface
Use a skin marker pen and tape measure to mark treatment area Cover margin of 5-10mm, surrounding the lesion
Apply cream to lesion about 1mm thick
Cream and dressings stay in place for 3 hours
After 3 hours, gently remove dressings and cream, using normal saline Settle patient into a comfortable position, maintained for 7-10 minutes for illumination (time may vary depending on light sources)
Large Aktilite®Lamp Check that lamp is calibrated to 37J/cm2
Using a Wood’s lamp check for photo fluorescence Porphyrins, abundant in neoplastic and dysplastic cells, will fluoresce pink (as seen in this picture)
Use the guide light to correctly position the lamp. This ensures lesion is fully illuminated Using a ruler, position the Aktilite®Lamp 5-8cm from the lesion Treatment will take between 7-10 minutes, depending on individual lamps
Following light illumination there is evidence of photo-bleaching
Cover lesion with dressing Advise patient to keep the area dry and covered for 24-48 hrs Patient is treated again after 7 days, as per clinical indication Lesion is assessed after 3 months
Light therapy powerpoint new
THE USE OF LIGHT THERAPY IN DERMATOLOGY Dr Ash Chadha
PhototherapyCertain types of electromagnetic radiationcan be used to treat some skin disorders.Blue light acne treatmentUVB therapyNarrowband UVB therapyUVA1 therapyTargeted phototherapyHome phototherapyPhotochemotherapy (PUVA)lasers/IPL treatmentPhotodynamic therapy (PDT) including Metvix PDTfor skin cancers
Blue light acne treatmentBlue light acne treatment is a non-invasive procedurethat uses light in the blue wavelength range of 405-420 nm to kill the Propionobacterium acnes or P.acnes bacteria in skin. This photodynamic therapy is FDA-approved for thetreatment of moderate acne vulgaris or acne vulgaristhat has not responded to other acne therapies.
How does it work?The bacteria in acne release porphyrins. These arenaturally occurring substances in the body, arising from thebreakdown of haemoglobin in red blood cells. When porphyrins absorb light of certain wavelengths, freeradical damage is produced, and this destroys the bacteria. Blue light acne treatment uses a narrow-band, high-intensity blue light source that is readily absorbed byporphyrins released by the bacteria causing acne.
What does the procedure involve?Blue light acne treatment is administered via a blue light deliverysystem. The procedure simply involves a patient sitting in front of a bluelight lamp for about 15 minutes. Generally 2 sessions per week over a4-week period is all that is required.Pre-treatment with ALA requires the topical application of ALA 30minutes prior to sitting in front of the blue light lamp for about 8 minutes.Treatments are usually spaced at 2-week intervals. The number oftreatments depends on the severity of acne and improvements seen.Blue light delivery systems can be purchased and self-administered athome, a dermatologist should oversee its use.
How effective is it?Several small studies have shown that blue light acne treatmentappears to improve acne vulgaris with a reduction in inflammationand the number of pustules and papules in some individuals.In one study, nodulocystic acne lesions worsened when treatedwith blue light.Further large, controlled studies are needed to prove their efficacyand long-term effects. Other treatments for acne may be moresuitable in the individual case.
UVB PhototherapyUVB phototherapy refers to irradiation with short wave ultraviolet radiation. Totreat the whole body, the patient, undressed, stands in a specially designedcabinet containing fluorescent light tubes.Traditionally, broadband UVB has been used, but increasingly,narrowband UVB phototherapy (311nm) is provided.Phototherapy cabinetWhole body unitIncreasing doses of UVB are given each exposure (three to five timesweekly), aiming to turn the skin slightly pink. Sometimes uncomfortablesunburn will occur, at its worst about 8 hours after treatment. This fades overthe next few days and should be treated with frequent and liberal emollients.The effect of UVB is similar to the sun. Excessive exposure contributes toaging skin and to the risk of skin cancer.
PsoriasisPsoriasis is a common inherited skin disorder, which may vary considerablyin extent and severity. Neither phototherapy nor any other available treatmenteffects a permanent cure.UVB is suitable for most people with extensive psoriasis. It may not suit thosewith very fair skin, or those whose psoriasis gets worse in sunlight.Initially most patients have their treatment three times a week. The first fewexposures will be short (less than 5 minutes). The length of exposure isgradually increased, according to the patients response, up to a maximum of30 minutes per session. Few patients require such long exposures, mostbeing controlled with shorter times.Most psoriasis patients will have their psoriasis cleared or much improvedafter 12 to 24 treatments. At this stage treatments will usually bediscontinued. Even without treatment, the skin may remain clear for somemonths. However, the psoriasis may later flare up again, and further UVBtreatment may be necessary.Those cases of psoriasis which appear to be resistant to UVB may still behelped by another form of ultraviolet treatment called PUVA, or othertreatments (e.g. ointments or tablets).
DermatitisUVB is occasionally used for severe cases ofdermatitis, especially atopic eczema. Frequencyand dosage of treatment is similar to that used forpsoriasis. However, a course of phototherapy mayneed to be more prolonged than that generallyrequired for psoriasis.
VitiligoUVB is one of the most effective treatments for vitiligo.Treatments must be cautious as the white skin burns easily. Itmay take several months to see an improvement.
Other skin conditionsMany other skin conditions have been effectivelytreated with UVB, including Generalised itch, Prurigo, Cutaneous T-cell lymphoma, Pityriasis lichenoides,and symptomatic dermographism.
Narrowband UVB phototherapyNarrowband UVB is now the most common form of phototherapy used to treatskin diseases (2008). Narrow-band refers to a specific wavelength of ultraviolet(UV) radiation, 311 to 312 nm. UVB phototherapy was formerly provided as abroadband source (290 to 320 nm).This range of UV radiation has proved to be the most beneficial component ofnatural sunlight for psoriasis. Narrowband UVB may also be used in thetreatment of many other skin conditions including atopic eczema, vitiligo, pruritus, lichen planus, polymorphous light eruption,early cutaneous T-cell lymphoma and dermographism.Compared with broadband UVB:•Exposure times are shorter but of higher intensity.•The course of treatment is shorter.•It is more likely to clear the skin condition.•Longer periods of remission occur before it reappears.
What does the treatment involve?Patients attend two to five times weekly. The patient is placed in a speciallydesigned cabinet containing fluorescent light tubes.The patient stands in the centre of the cabinet, undressed except for underwear,and wears protective goggles. Usually the whole body is exposed to the UVB fora short time (seconds to minutes).The amount of UV is carefully monitored. A number of protocols exist dependingon the individuals skin type, age, skin condition and other factors.The skin may remain pale or turn slightly pink (the Minimal Erythemal Dose) aftereach treatment.Patches of psoriasis generally start to become thinner after five to ten treatments.Most patients with psoriasis require 15 to 25 treatments to clear.
Side effectsNarrow-band UVB can result in burning, just like sunlight andbroadband UVB.Frequent emollients should be applied to burned skin, and ifrecommended by the dermatologist/ nurse specialist,topical steroids.It sometimes provokes polymorphous light eruption.Long term exposure to ultraviolet radiation ultimately causesskin ageing and skin cancers. Although the risk from narrow-band UVB is unknown, research to date suggests it is no morerisky than broadband UVB and probably less risky thanphotochemotherapy (PUVA).
PUVA (photochemotherapy)What is PUVA?PUVA or photochemotherapy is a type of ultraviolet radiation treatment (phototherapy) used for severe skin diseases.PUVA is a combination treatment which consists of Psoralens (P) and thenexposing the skin to UVA (long wave ultraviolet radiation). It has beenavailable in its present form since 1976.Psoralens are compounds found in many plants which make the skintemporarily sensitive to UVA. The ancient Egyptians were the first to use psoralens for the treatment of skindiseases thousands of years ago. Medicine psoralens include methoxsalen (8-methoxypsoralen), 5-methoxypsoralen and trisoralen.
Whole body PUVAFor oral PUVA, methoxsalen capsules are taken two hours before the appointment fortreatment. For bathwater PUVA, the patient soaks in a bath containing a solution ofpsoralens. In most cases, treatment is undertaken two or three times each week.During treatment, the patient usually stands in a cabinet containing 24 or more 6-foot longUVA fluorescent bulbs.The patient should always wear goggles to protect the eyes from exposure to the radiation.Usually, he or she is dressed only in body exposure. Sometimes just arms and legs maybe exposed to the radiation, in which case the patient should wear the same clothing eachtreatment to prevent inadvertently exposing a new area of skin.The UVA lamps stay on for increasing lengths of time, starting with about one minute andextending for up to half an hour. Their may be fans and/or air conditioning to cool thecabinet, as it tends to get very warm with more prolonged treatment times. hole body PUVA cabinets
Localised PUVAThose patients requiring treatment to small areas only may be treated using a smallerhand and foot unit. Bathwater PUVA may be suitable. In this case the hands and/or feetare soaked in a dilute solution of methoxsalen for 30 minutes, then immediately exposedto UVA.A few patients may be treated with topical PUVA – a psoralens lotion or gel is applied tothe affected areas 10 minutes before UVA exposure PUVA hand unit
What is PUVB?PUVB is the combination of Psoralens and UVB (short wavelength ultraviolet radiation).This is rarely used, as the wavelength that activates the psoralens most effectively is inthe UVA range.Can sunlight be used for PUVA?Where PUVA cabinets are unavailable, some dermatologists have recommendedpatients are exposed to sunlight after taking psoralens by mouth orapplying psoralenstopically. The oral psoralens has usually been trisoralen as this is slightly safer thanmethoxsalen.Unfortunately, sunlight is unpredictable – it is difficult to get the correct dose. Too little,and it is ineffective. Too much, and a nasty blistering burn may occur.
What is PUVA used for?PUVA may be used to treat various skin disorders, including:•Psoriasis•Dermatitis•Vitiligo•Polymorphic light eruption•Cutaneous T-cell lymphomaThe number and the frequency of PUVA treatments willdepend on the condition being treated and individual factors.PUVA is used infrequently in New Zealand, asnarrowband UVB phototherapy has been shown to be nearlyas effective. UVB is also less complicated and less risky.
Side effects of PUVAPUVA has some risks and side effects.BurningAn overdose of PUVA results in a sunburn-like reaction called phototoxic erythema. It is more likely in fair skinned patients who sunburneasily. A burn is most likely 48 to 72 hours after the first two or three treatments.Sensitive areas such as breasts and buttocks may need to be covered for all or part of the treatment.Avoid photosensitizers such as certain oral medications, perfumed cosmetics and applications of coal tar.If the treated skin becomes pink the dose of UVA should not be increased. One or more treatments may be missed.Unfortunately, phototoxic erythema can persist for longer than sunburn from natural sunlight. Moisturizers and painkillers can reduce thediscomfort.ItchingTemporary mild pricking or itching of the skin is common after treatment.The skin is often rather dry. Apply a moisturiser frequently. Antihistamine tablets may help.NauseaNausea occurs in a quarter of those treated with psoralens. If it occurs, tell your phototherapy nurse or doctor. Nausea is less if themethoxsalen capsules are taken with food, or the dose is reduced. Antiemetic tablets can be prescribed.TanningPUVA usually leads to tanning which lasts several months. Although the skin appears brown it may still burn easily on sun exposure. Tanningfrom UVA is not as protective as tanning from combined wavelengths occurring in natural sunlight.Eye damageIf the eyes are not protected from UV radiation, keratitis may occur. This results in red sore gritty eyes and can be very unpleasant.Damage to the lens in the eye leading to cataracts is another possible risk.Skin aging and skin cancerExtensive PUVA treatment results in premature aging changes and can increase the chance of skin cancer.•Dry skin and wrinkles•Discolouration: broken blood vessels, freckles, lentigines•Squamous cell carcinoma, and less often, basal cell carcinoma and melanomaFair skinned individuals or those with previous sun or radiation damage are most at risk. This is not a concern for most patients, who receivePUVA therapy for two or three months only.Patients on long term maintenance therapy should have their skin checked by the specialist at least every 6 months. Bring any new moles,sores which are slow to heal, or growing lumps to the doctors attention.Usually, but not always, skin cancers are readily curable. When significant ageing changes are evident or skin cancers occur, it becomesunwise to continue PUVA.PregnancyThere is no evidence to suggest that PUVA will damage a developing baby. However, should a patient become pregnant, or suspect she ispregnant, during a course of treatment, we advise our patients to stop PUVA treatment immediately.
Treatment of different skin conditionsPsoriasisPUVA is usually reserved for patients in older age groups, or for those whose psoriasisis either severe or not responding adequately to more conventional forms of treatment.For example, psoriasis with very thick and scaly plaques on trunk and limbs. Inapproximately 90% PUVA is effective in clearing psoriasis, and can often control it aslong as treatments are continued (although this is rarely recommended). Psoriasis inbody areas shielded from light (e.g. scalp and body flexures) may not clear satisfactorilywith PUVA.Initially most patients have their treatment two or three times a week. The first fewexposures will be short (less than 5 minutes). The length of exposure is graduallyincreased, according to the patients response, up to a maximum of 30 minutes persession. Few patients require such long exposures, most being controlled with shortertimes.Most psoriasis patients will have their psoriasis cleared or much improved after 12 to 24treatments. At this stage treatments may be reduced to once a week or less. Evenwithout treatment, the skin may remain clear for some months. However, the psoriasismay later flare up again, and PUVA may be recommenced.Those few cases of psoriasis which appear to be resistant to PUVA may still be helpedby combining PUVA with other treatments (e.g. ointments or tablets).
Eczema or dermatitisPUVA is occasionally used for severe cases of dermatitis. Frequency and dosage oftreatment is similar to that used for psoriasis. However, a course of phototherapy mayneed to be more prolonged than that generally required for psoriasis.Mycosis fungoidesFor this rare skin form of cutaneous T-cell lymphoma, PUVA is usually given twice aweek at first, using shorter exposures than for psoriasis. When the skin is clear,treatment is given less frequently. If PUVA is stopped, the condition sometimesrelapses.Polymorphic light eruptionPolymorphic light eruption (PMLE) is a common light sensitivity disorder. A six weekcourse of PUVA in the spring or early summer usually gives patients good protectionfor the remainder of the summer.A further course of treatment will be necessary if protection is required in subsequentyears.VitiligoPatients with vitiligo have areas of completely white skin. PUVA can bring about somerepigmentation, particularly for vitiligo of the face, and in dark-skinned patients.Results for other body sites and white-skinned patients are less encouraging.Treatment is usually twice a week for two years. Even then, complete repigmentationcannot be guaranteed and relapse is possible.
“NICE Endorsement for PDT forNMSCEvidence of efficacy of this procedure for the treatmentof basal cell carcinoma, Bowen’s disease and actinic(solar) keratosis is adequate to support its use for theseconditions, provided that the normal arrangements arein place for consent,audit and clinical governance.”Document available at www.nice.org.uk
The size of the problem•Non-melanoma skin cancers (NMSC) are the mostfrequently observed neoplasms worldwide•NMSC is the most common type of cancer diagnosedin the UK each yearNMSC include:•basal cell carcinoma•squamous cell carcinoma•Their incidence has steadily been growing
National guidelinesNational guidelines for the treatment of NMSCDH guidance•Improving Outcomes: A Strategy for Cancer January 2011•Department of Health Guidance and competencies for theprovision of services using GPs with a special interest (GPwSIs)2007•The Manual for cancer services: skin measures‘ November 2008NICE Guidance•Improving Outcomes for People with Skin Tumours includingMelanoma (update): The Management of Low-risk Basal CellCarcinomas in the Community May 2010•Improving outcomes for people with skin tumours includingmelanoma: the manual (2006 guidance) 22 February 2006
Results of sun damagePre-cancerous and cancerous lesions resultingfrom sun damage: Actinic (solar) keratosis Bowen’s disease Squamous Cell Carcinomas Basal Cell Carcinomas Melanoma
Actinic keratosis AKs are: Potentially pre-malignant skin tumours 1 mainly due to long-term exposure to the sun in susceptible persons and may progress to squamous cell carcinoma11. Journal of the American Academy of Dermatology 1995; 32:95-98
Actinic keratosis Red scaly lesions Single or multiple lesions Generally asymptomatic May be difficult to distinguish more severe AK and some SCCs on clinical grounds Not possible to tell which AKs will progress to SCC1,2 AKs can be treated in primary care1. Yantsos VA et al. Sem in Cutan Med Surg 1999; 18(1): 3-142. Cockerell CJ. J Am Acad Derm 2000; 42(1) part 2: S11-S17
Actinic keratoses Prevalence of AK varies with geography UK prevalence - 5.9%-15.4% of population aged 40+1 Australian prevalence – 40% of the population21. Memon et al. Br J Dermatol 2000; 142: 1154-11592. Green et al. J Am Acad Dermatol 1988; 19: 1045-1052
Actinic keratosis1. Adapted from Harvey I et al. Br J Cancer 1996; 74: 1302-1307
The presentation of AKA few superficial Many small but visible Multiple “thicker” AKs“thin” AKs AKs, which may be many of which are quite palpated hyperkeratotic
Bowen’s DiseasePersistent indurated discoid scaly areacommonly on lower legs. Bowen’s disease or carcinoma in situ ielocalised neoplastic degneration limited to theepidermis3-5% risk of Bowen’s transforming to SCC
Basal cell carcinoma BCC accounts for more than three quarters of skin cancers in the UK1 Typical case is on the face of a 70 yr old Slow growing –non-urgent referral Locally invasive Rarely metastasise1. Cancer Bacup UK
ManagementMost AKs can be safely managed in primarycare thus reducing waiting times for more severelesionsTreatment options for AK include: Surgery (Curettage or excision) Cryotherapy Topical therapy Photodynamic therapy
Photodynamic Therapy (PDT)• Metvix® Mechanism of Action• The active ingredient of Metvix® is methyl aminolevulinate. Metvix®is absorbed selectively by diseased cells and results in accumulation of photoactive porphyrins(PAP)in these cells. Subsequent illumination with a light dose of approximately 631nm wavelength and a total light dose of 37 joules/cm2, leads to the creation of reactive oxygen, which rapidly leaving the eliminates the cancerous cells while healthy skin unharmed.
Topical PDT therapy • Key features of Metvix® Methyl aminolevulinate (MAL) Compared to other NMSC treatments • •Effective in BCC, Bowen’s and AKs • •Selective accumulation in lesions • •Non-invasive • •Minimal scarring • •Fast healing • •Excellent cosmetic outcome compared to surgery • •High patient satisfaction • •Minimal side effects1. Efudix. Summary of Product Characteristics. May 2004.2. Smith SR & Piacquadio DJ. Poster Presented at the Annual Meeting of AAD, Washington, USA, February 2004.
TopicalPhotodynamic Therapy (PDT)Clinical Protocol•Follow clinical protocol•Check diagnosis (histology if present)•Ensure you gain consent (verbal/written)•Take time to explain the procedure. Whathappens before, during and after light treatment•Repeat treatment after 7 days (if indicated).Follow up after 3 months•Keep clear and accurate records Infection Prevention & Control •Hand hygiene before and after each procedure •Personal Protective Equipment (PPE) •Equipment is single patient use, where possible •Wipe down equipment (bed, goggles, lamp) and surfaces between patients •Encourage patients to use alcohol hand gel on entering
History of LasersAlbert Einstein (1905) used Plancks relationship to explain the results ofthe photoelectric effect which showed that the energy E of ejectedelectrons was dependent upon the frequency f of incident light as describedin the equation E=hf. It is ironic that in 1921 Albert Einstein was awardedthe Nobel Prize for this discovery, though he never believed in particles andacknowledged that he did not know the cause of the discrete energytransfers (photons) which were contradictory to his continuous field theoryof matter!All these fifty years of conscious brooding have brought me no nearer to theanswer to the question, What are light quanta? Nowadays every Tom, Dick andHarry thinks he knows it, but he is mistaken. (Albert Einstein, 1954)
Theodore Harold MaimanTheodore Harold "Ted" Maiman (July 11,1927 – May 5, 2007) was an Americanphysicist who made the first laser (LightAmplification by Stimulated Emission ofRadiation). Theodore Harold Maiman (1927-07-11)July 11, 1927 Born Los Angeles, California Inventing, Demonstrating, and Known for Patenting the Worlds First LASER Stuart Ballantine Medal (1962) Notable awards Wolf Prize in Physics (1983) Japan Prize (1987)
Absorption of energyAbsorption of energy: An atom absorbsenergy in the form of heat, light, orelectricity. Electrons may move from alower-energy orbit to a higher-energyorbit.
Ruby Lasers A ruby laser consists of a flash tube ( like you would have on a camera ), a ruby rod and two mirrors (one half-silvered). The ruby rod is the lasing medium and the flash tube pumps it.
2. The flash tube fires and injects light into the ruby 4. Some of these photons run in a direction parallelrod. The light excites atoms in the ruby. to the rubys axis, so they bounce back and forth off the mirrors. As they pass through the crystal, they stimulate emission in other atoms. 5. Monochromatic, single-phase, columnated light 3. Some of these atoms emit photons. leaves the ruby through the half-silvered mirror -- laser light!
Laser ClassificationsLasers are classified into four broad areas depending on the potential for causing biologicaldamage. When you see a laser, it should be labeled with one of these four class designations:•Class I - These lasers cannot emit laser radiation at known hazard levels.•Class I.A. - This is a special designation that applies only to lasers that are "not intended forviewing," such as a supermarket laser scanner. The upper power limit of Class I.A. is 4.0 mW.•Class II - These are low-power visible lasers that emit above Class I levels but at a radiant powernot above 1 mW. The concept is that the human aversion reaction to bright light will protect aperson.•Class IIIA - These are intermediate-power lasers (cw: 1-5 mW), which are hazardous only forintrabeam viewing. Most pen-like pointing lasers are in this class.•Class IIIB - These are moderate-power lasers.•Class IV - These are high-power lasers (cw: 500 mW, pulsed: 10 J/cm2 or the diffuse reflectionlimit), which are hazardous to view under any condition (directly or diffusely scattered), and are apotential fire hazard and a skin hazard. Significant controls are required of Class IV laser facilities.. Laser warning sign