primenenie lazerov v meditsine

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primenenie lazerov v meditsine primenenie lazerov v meditsine lazernie biomeditsinskie texnologii vinujdennoe izluchenie, yavlyayusheesya protsessom usileniya izlucheniya texnicheski realizuetsya v zavisimosti ot generiruemoy dlini volni v vide lazera, mazera ili grazera (laser – light amplification by stimulated emission of radiation–usilenie sveta putem vinujdennogo izlucheniya) ili v vide mazera (maser–microwave amplification by stimulated emission of radiation–mikrovolnovoe usilenie putem vinujdennogo izlucheniya) ili v vide grazera (graser–gamma-ray amplification of stimulated emission of radiation–usilenie gamma-luchey putem vinujdennogo izlucheniya). rekomenduemaya literatura prikladnaya lazernaya meditsina/pod redaktsiey x.-p. berliena, g.y. myullera//uchebnoe i spravochnoe posobie: interekspert.moskva. 1997. 343 s. nemnogo istorii printsip deystviya lazera bil opisan eshe eynshteynom v dalekom 1917 godu. v 1939 godu molodoy sovetskiy ucheniy v.a. fabrikant vernulsya k vvedennomu eynshteynom v fiziku ponyatiyu vinujdennogo izlucheniya. issledovaniya valentina aleksandrovicha fabrikanta zalojili prochniy fundament dlya sozdaniya lazera. odnako texnicheskoe sozdanie istochnika vinujdennogo izlucheniya proizoshlo tolko v pyatidesyatie godi blagodarya tvorcheskoy rabote sovetskix uchenix aleksandra proxorova, nikolaya …

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ez nekotoroe vremya bil isprobovan uje lazer s dlinoy volni v 1060 nm, chto yavlyaetsya blijney ik-oblastyu spektra. v kachestve aktivnoy sredi v etom lazere vistupali steklyannie sterjni, legirovannie neodimom. sozdat svoy perviy lazer meymanu udalos posle devyati mesyatsev neprerivnoy gonki, rabotaya v laboratorii hughes research, kotoraya sorevnovalas s drugimi vedushimi kompaniyami, takimi kak lincoln labs, ibm, westinghouse, siemens, rca labs, ge, bell labs, trg. zatem emu eshe dolgo prishlos borotsya za svoy prioritet, kotoriy v kontse kontsov stal obshepriznannim. poslednie godi jizni meyman zanimalsya texnologiyami primeneniya lazerov v meditsine. deystvie lazera deystvie lazera nachinaetsya s vozbujdeniya atomov i ix perexodov na energeticheskie urovni f1 i f2. zatem kajdiy vozbujdenniy atom spontanno (samoproizvolno, t.e. nevinujdenno) izluchaet kvant (nelazernogo izlucheniya) i, poteryav chast svoey energii, perexodit na metastabilniy uroven e. dalee, pod vozdeystviem vinujdayushego kvanta s lazernoy dlinoy volni (takie kvanti est v izluchenii lampi nakachki) atom izluchaet eshe odin takoy …

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sii. s pomoshyu opticheskoy nakachki v dvuxurovnevoy sisteme nelzya proizvesti inversiyu naselennosti. po-drugomu delo obstoit v sistemax s tremya i bolshim chislom urovney. v trexurovnevoy lazernoy sisteme pri ochen intensivnoy nakachke s urovnya 1 na uroven 3 mojno poluchit na urovne 2 bolee visokuyu naselennost, chem na urovne 1. esli sistemu s tremya urovnyami rasshirit na eshe odin uroven 2’ mejdu urovnem 1 i urovnem 2, to mojno izbejat problem trexurovnego lazera v otnoshenii korotkoy po vremeni inversii naselennosti, pri uslovii, chto uroven 2’ yavlyaetsya ochen korotkojivushim. esli lazerniy perexod osushestvlyaetsya s urovnya 2 na uroven 2’, to uroven 2’ pri rabote lazera vvidu ego korotkogo sushestvovaniya postoyanno opustoshaetsya na osnovnoy uroven. v etoy konfiguratsii daje pri neznachitelnoy moshnosti nakachki mojno postoyanno coxranyat inversiyu nase- lennosti mejdu urovnyami 2 i 2’. lazeri s 4-mya urovnyami mogut poetomu rabotat v neprerivnom rejime (cw - continuous wave). opticheskaya nakachka esli aktivnuyu sredu …

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va. v kachestve aktivnoy lazernoy sredi mogut primenyatsya vse materiali, u kotorix mojno obespechit inversiyu naselennosti. eto vozmojno u sleduyushix materialov: a) svobodnie atomi, ioni, molekuli, ioni molekul v gazax ili parax; b) molekuli krasiteley, rastvorennie v jidkostyax; v) atomi, ioni, vstroennie v tverdoe telo; g) poluprovodniki; d) svobodnie elektroni. po vidu lazernoy aktivnoy sredi razlichayut gazovie, jidkostnie, poluprovodnikovie i tverdotelnie lazeri. tvyordotelnie lazeri k tverdotelnim otnosyatsya: rubinoviy (694 nm), granatoviy s neodimom (1064 nm), aleksandritoviy (700-820 nm), golmieviy (2100 nm), erbieviy (2940 nm). osobennosti: parametri izlucheniya zavisyat ot opticheskix kachestv ispolzuemogo kristalla. neodnorodnosti kristallicheskoy strukturi mogut serezno ogranichivat kogerentnost lazera. kristalli postoyanno podverjeni razrusheniyam; kontsentratsiya aktiviruyushix ionov zadaetsya v protsesse izgotovleniya lazera i yavlyaetsya opredelennoy velichinoy dlya dannogo kristalla. primenenie: xirurgiya istochnik nakachki: impulsnaya lampa, lazerniy diod. gazovie lazeri k gazovim otnosyatsya: argonoviy (351 - 529 nm) eksimerniy (193 - 353 nm) na parax medi (510 - 578 nm) …

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m 570—640 nm istochnik nakachki: drugoy lazer, impulsnaya lampa. poluprovodnikovie lazeri poyavlenie poluprovodnikovix lazerov sovershilo revolyutsiyu po prichine ix ekonomichnosti za schet visokogo koeffitsienta poleznogo deystviya (do 60 - 80% v otlichie ot 10-30% pri traditsionnix), malogabaritnosti, nadejnosti. rabochee telo – poluprovodnikoviy lazerniy diod. elektricheskaya i opticheskaya nakachka. bolshoy vklad v sozdanie dannogo tipa lazerov vnesli raboti j.i. alferova. on udostoen nobelevskoy premii po fizike (premiya 2000 goda za razrabotku poluprovodnikovix geterostruktur i sozdanie bistrix opto- i mikroelektronnix komponentov). izvestni linii lazernoy generatsii ot ultrafioletovoy oblasti spektra (100 nm) do millimetrovix dlin voln, v dalnem ik-diapazone lazeri plavno perexodyat v mazeri. intensivno vedutsya issledovaniya v oblasti lazerov v diapazone rentgenovskix voln. no prakticheskoe znachenie priobreli tolko dva-tri desyatka tipov lazera. naibolee shirokoe biomeditsinskoe primenenie poluchili: so2-lazer, lazer na ionax argona i kriptona, nd:yag-lazeri neprerivnogo i impulsnogo rejima, lazeri na krasitelyax neprerivnogo i impulsnogo rejima, he-ne-lazer, eksimernie lazeri, nd:yag-lazeri s udvoenie …

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primenenie lazerov v meditsine primenenie lazerov v meditsine lazernie biomeditsinskie texnologii vinujdennoe izluchenie, yavlyayusheesya protsessom usileniya izlucheniya texnicheski realizuetsya v zavisimosti ot generiruemoy dlini volni v vide lazera, mazera ili grazera (laser – light amplification by stimulated emission of radiation–usilenie sveta putem vinujdennogo izlucheniya) ili v vide mazera (maser–microwave amplification by stimulated emission of radiation–mikrovolnovoe usilenie putem vinujdennogo izlucheniya) ili v vide grazera (graser–gamma-ray amplification of stimulated emission of radiation–usilenie gamma-luchey putem vinujdennogo izlucheniya). rekomenduemaya literatura prikladnaya lazernaya meditsina/pod redaktsiey x.-p. berliena, g.y. myullera//uchebnoe i spravochnoe posobie...

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