Page 48 - Mike's published articles
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TABLE2.Ananalysisofthenumber,N,oftreatmentsesionsnededforsucesfulremovalof tatos.Eachsesionwouldconsistofmanylaserpulsestoagivensite.
NumberofSesions(N)
Pulse Profesional Amateur Reference
Lasertype EnergyDensity
JIcm2 width/ns tatos tatos
Ruby
6 -10 25 *13.1; 9.7; 9 *5.6; 2.5 ; 3 17 6-8 40 6-10 4-6 18
Ruby Nd: YAG
8-12 8 4-8 3-4 18
(1064nm) Nd: YAG
8 2 -4 N/A 18 8-10 28 *5Ø%>Nd:YAGN/A 19
(532nm) (not quoted) Ruby
Nd: YAG
(1064 nm) Nd: YAG
(532nm) (notquoted, posibly5)
42% =Nd: YAG bestforgrens
8% >Nd:YAG 20% >Ruby 19 8veryefectiveforredinkN/A19
10-14 8
*Thedatafor280casestudies.Thefirstnumberisthemean,thesecondthestandardeviation andthethirdthemodeofthedistribution. *>means"beterthanwith",=means"equalyefectiveas".
Table2showsananalysisoftheNumber,N,oftreatmentsesionsnededforsucesfulremovalof tatos.Eachsesionwouldconsistofmanylaserpulsestoagivensite.Beforeanalysingtheclinicaldata, weshouldrememberthatthefluenceandfluxcharacteristicsofalaserarenotreadilymeasuredwithany acuracy.Theintensityofalasercanvaryinanarbitrarymaneracrositsdiameterandsothesecharac- teristicsrepresentanaverageoverthelaserbeamcrossection.Ifthedistributionofintensityacrosthe diameterisindedarbitrary,thisaverageisquitemeaningles.Forexample,"hotspots"canreadilyarise, givingordersofmagnitudemorefluenceandfluxatsuchpointsthanwouldbecalculatedfrompower meterdataintegratedacrosthefuldiameter.Thesecanhaveahighlydisproportionatefectonthe decompositionmechanisminitiatedbysuchalaser.Theonlysatisfactoryroutetomeaningfulmeasure- mentsoffluenceorfluxistoensurethatthelaserisoperatedwithawelcontroledandknownintensity distributionacrositsdiameter.ThedistributionofchoiceisusualyGausian,beingarangedbyhaving thelaseroperateinTEM0.ItisposibletosodesignthecavityofalasertoproduceaTEM0profile20,
sothatthisisthesimplestcontroledistributionofintensitytobtain.However,energyislostwhenthe laserisoperatedinthismanerandsosomemanufacturerswilsacrificethistransversemodequalityfor power.Inthesecases"hotspots"wilundoubtedlyocurandwilapearrandomlyinpositionwithinthe diameterandwithtime.ThehighqualityTEM0profileofthelaserusedinthefirststudy'7reportedin
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