Medical Light Sources

• Introduction• Light therapy

– Full spectrum– UV– IR

• Applications– Endoscopy– Medical LASER

Light Therapy in History• Tuberculosis since

1895• Rachitis since 1921

Sanatoriums in Davos, Braunwald….7h in sunlight

Generation of Vitamin D3– Produced in the skin– Needs UV-B (290 - 315

nm)

Vitamin D3

Utilisation of Vitamin A660-668Red

Heat Therapy880-904IR

Vitalization446Blue

Tanning skin315-400UV-A

Synthesis of Vitamin D3280-315UV-B

Disinfection200-280UV-C

Important forWavelength[nm]

SpectralRange

Lack of Light Causes• Depressions• Sleep disorder

Therapy:½ h with 10.000 Lux oror 2 h with 2500 Lux

Decomposition of Melatonin

Decomposition of MelatoninSu

ppre

ssio

n of

Mel

anto

nin

[%]

Radiant flux density [µW*h/cm2] Time of day

Time of irradiation (3h)

Con

cent

ratio

nof

Mel

anto

nin

Icterus neonatorumor Crigler-Najjar Syndrome

Decomposition of erythrocytes in the first days after birthForming of Bilirubin causes the icterus

Exposure with blue light (460 nm) leads to Lumirubin

Philips Special Blue lampsF20T12/BB or F40/BB

Philips Special Blue lamps F20T12/BBor F40/BB

BaMgAl10O17:Eu2+

Wavelength [nm]

Em

issi

on In

tens

ity[a

.u.]

Therapy for Skin Diseases

Acne• Light with wavelength of 415 nm• Oxygen radicals are generated on

the skin surface

Bacteria are destroyed

Problem: proliferation hyperkeratosis– scarring– increased cell devision

α-Ba3Y(BO3)3:Eu

Therapy for Skin diseases

Neurodermatitis• UV-B (311 nm, LaB3O6:Bi3+,Gd3+)• In severe cases additionally UV-A (340 - 400 nm

LaPO4:Ce3+)

Wavelength [nm]

Em

issi

on in

tens

ity[a

.u.]

Tanning of skinUV-A (315-400nm) • 95% of radiation• Tanning of the epidermis

immediate reactionshort term effect

UV-B (280-315nm)• 5% of radiation• Tanning of the deeper skin

takes 2-3 dayslong term effect

Oxidation of Melanin causesthe tanning.

Wavelength [nm]

Em

issi

on in

tens

ity[a

.u.]

DisinfectionUV-C (200 - 280 nm)• Absorbtion of the DNA at 254 nm

degeneration of thegenetic information

reproduction is inhibited

• 99.99% of microorganism are killed• Works in spits of a second

Absorption curve of the DNA

Wavelength [nm]

Inte

nsity

[a.u

.]

254nmSpectral efficiency curveof cell inacitvation

Infrared Therapy• rheumatism

• neurodermatitis

• backache

• cancer therapy (high energy IR-A)

IR-A and IR-B

• Incandescent bulb with a filter

• YAG:Nd Laser

IR-C

• heated-up ceramic

Endoscopy• Light source:

• Xenon-Lamp• LED

• Fibre-optic• Glasfibre• Polymeric optical fiber

high refractiveindex

Endoscopy techniques

Medical LASER• Erasing of tattoos YAG:Nd (1064 nm) and Ruby (694 nm)• Correction of eyes ArF (193 nm) and Ti:Saphir (800 nm)• Hair removal Alexandrit Laser (755 nm)• Laser scalpel CO2-Laser (10.6 µm), YAG:Nd (1064 nm)

Warning at the End

Enjoy the sun…..

Warning at the End

Enjoy the sun…..but not too much!

Thanks for your attention!

References• Light and Lasers (Jerry Joseph Wilmink, Vanderbilt University, Nashville)• Leben mit optischer Strahlung (Joachim Fisch, Karin Bieske)• Informationen zur Tiefenwärme (www.pooldoktor.at)• Licht in der Geschichte der Medizin (Dr. med. Urs Stillhard)• Alternative Medizin – Die Heilkraft des Lichts

(www.mweisser.50g.com/licht.htm)• Laser in der Medizin (Seminar Vortrag von Steffen Eich)• www.wikipedia.org• Lichttechnik und Leuchtstoffe (Vorlesungsskript Prof. Dr. Thomas Jüstel)