Ukufaniswa kwe-Magnetic Resonance
I-MRI ibhekisela ekucabangeni kwemifanekiso kagesi . Eqinisweni, igama elifanele lalo cwaningo luyisithombe se- nuclear magnetic resonance (NMRI), kodwa lapho le nqubo isetshenziselwa ukusetshenziselwa ukunakekelwa kwezempilo igama elithi "nuclear" lalizwakala libi kakhulu futhi lashiywa ngaphandle igama elamukelweyo.
I-MRI isekelwe ezimisweni zomzimba nezamakhemikhali ze-nuclear magnetic resonance (NMR), inqubo esetshenziselwa ukuthola ulwazi mayelana nemvelo yamamolek'hule.
Indlela i-MRI esebenza ngayo
Ukuqala, ake sibheke izingxenye zomshini we-MRI. Izingxenye ezintathu eziyisisekelo zomshini we-MRI yizi:
- I-magnet eyisisekelo
Ingxenye enkulu kunazo zonke ze-MRI yi- magnet oyinhloko . Ukuthuthukisa insimu yamagnetic yamandla adingekayo ukwakha izithombe ze-MRI kwakuyisiqalo sokuqala sokunqoba ekuthuthukiseni lobu buchwepheshe. - Amagnethe we-gradient
Amaginethi we-gradient yiyona ingxenye "yokuhleleka kahle" kwengxenye yomshini we-MRI. Bavumela i-MRI ukuba igxile kwingxenye ethize yomzimba. Amaginethi ama-gradient nawo anesibopho "somsindo othakazelisayo" ku-MRI. - Ikhoyili
Eceleni kwengxenye yomzimba wakho okucatshangelwayo ikhoyili . Kunamakhoyili okwenziwe amahlombe, amadolo, nezinye izingxenye zomzimba. Ikhoyili izokhipha imisebe yomsakazo eyenza i-MRI ingenzeka.
I-Magnet Primary
I-magnet okuhlala unomphela (njengenhlobo oyisebenzisayo emnyango wakho wesiqandisisi) enamandla okwanele ukusebenzisa eMRI ingaba yindleko enkulu ukukhiqiza futhi inzima kakhulu ukuyigcina.
Enye indlela yokwenza i-magnet ukubopha ucingo kagesi bese uqhuba i-current ngokusebenzisa ucingo. Lokhu kudala insimu yamagnetic phakathi nendawo yekhoyili. Ukuze udale inkundla enamandla ngokwanele yokwenza iMRI, amakhoyili wocingo akufanele abe nokuphikiswa; ngakho-ke bahlambalazwa nge-helium eyisikhilimu ekushiseni okungama-450 degrees Fahrenheit ngaphansi kwe-zero!
Lokhu kuvumela ukuthi amakhoyili athuthukise amasimu omhlaba we-1.5 kuya ku-3 Tesla (amandla angama-MRI amaningi wezokwelapha), izikhathi ezingaphezu kuka-20 000 ezinamandla kunomhlaba wamagnetic.
Amagnethi amakhulu
Kunezimboni ezintathu ezincane ngaphakathi komshini we-MRI obizwa ngokuthi amamitha we-gradient. Lezi zimakethe zincane kakhulu ukuthi i-magnet eyisisekelo (cishe ngo-1/1000 inamandla), kodwa ivumela insimu magnetic ukuthi iguquke ngokuqondile. Yilezi amamitha ama-gradient avumela izithombe "zetekisi" zomzimba ukuthi zidalwe. Ngokushintsha ama-magnets, i-magnetic field ingagxila ngokuqondile engxenyeni ekhethiwe yomzimba.
Ikhoyili
I-MRI isebenzisa izindawo zama-athomu e-hydrogen ukuze zihlukanise phakathi kwezicubu ezahlukene ngaphakathi komzimba womuntu. Umzimba womuntu uhlanganiswa ngokuyinhloko ngama-athomu e-hydrogen (63%), ezinye izakhi ezivamile zikhona oksijini (26%), i-carbon (9%), i-nitrogen (1%), kanye namanani amancane e-phosphorus, i-calcium, ne-sodium. I-MRI isebenzisa impahla yama-athomu okuthiwa "i-spin" ukuhlukanisa umehluko phakathi kwezicubu ezinjenge-muscle, fat and tendon.
Ngesiguli emshinini we-MRI futhi i-magnet ivuliwe, i-nuclei yama-athomu e-hydrogen ihlotshaniswa kwesinye seziqondiso ezimbili. Lezi nuclei ze-athomu ze-hydrogen zingashintsha ukujikeleza kwazo, noma i-precess, ekuqondeni okuhlukile.
Ukuze uphendule olunye uhlangothi, i -coil iveza umsakazo (RF) owenza lokhu kuguqulwa (imvamisa yamandla adingekayo ukwenza lokhu kuguqulwa kuqondile, futhi kuthiwa yiLarmour Frequency).
Isignali esetshenziselwa ukudala imifanekiso ye-MRI itholakala kumandla akhishwe ama-molecule ashintshe noma afakazela phambili, kusukela emandleni abo aphezulu ukuya esimweni sabo esincane. Lokhu kuhanjiswa kwamandla phakathi kwe-spin states kubizwa ngokuthi i-resonance, futhi ngaleyo ndlela ibizo elithi imagination resonance magnetic .
Ukubeka konke ndawonye
Ikhoyili iphinde isebenze ukuthola amandla anikelwe yi-induction magnetic kusukela ekuthuthukiseni kwama-athomu.
Ikhompyutha ihumusha idatha futhi idala izithombe ezibonisa izici ezahlukene ze-resonance zezinhlobo ezahlukene zezicubu. Sibona lokhu njengesithombe se-shades of grey - ezinye izicubu zomzimba zibonakala zibe mnyama noma zikhanya, konke kuye ngezinqubo ezingenhla.
Iziguli ezihlelwe ukuthi zizitholele i-MRI zizocelwa imibuzo ethile ukuze kutholakale ukuthi i-MRI iphephile yini kulowo ogulayo. Ezinye zezinkinga ezizoxazululwa zihlanganisa:
- Insimbi emzimbeni
Iziguli ezinezifutho zensimbi emzimbeni zidinga ukuxwayisa abasebenzi be-MRI ngaphambi kokuhlolwa kwe-MRI. Ezinye izimila zensimbi zihambisana ne-MRI, kufaka phakathi izimila eziningi zomuthi we-orthopedic . Kodwa-ke, izimpembelelo ezithile zivimbela iziguli ukuba zingenaso i-MRI, njenge-aneurysm emaceleni ebuchosheni nasemihlotsheni yamehlo ensimbi . - Amadivayisi afakiwe
Iziguli ezine-pacemakers noma i- defibrillator zangaphakathi zidinga ukuxwayisa abasebenzi be-MRI, njengoba la madivayisi avimbela ukusetshenziswa kwe-MRI test. - Izembatho / Ukucweba
Noma yikuphi izingubo zensimbi noma izinto zokugqoka kufanele zisuswe ngaphambi kokufunda isifundo se-MRI.
Izinto zensimbi eziseduze ne-MRI zingaba yingozi. Ngo-2001, umfana oneminyaka eyisithupha ubudala wabulawa ngenkathi i-tank oksijeni ishaya ingane. Lapho i-MRI magnet ivuliwe, ithangi le-oksijini lalingene eMRI, futhi ingane yashaywa yinto enzima. Ngenxa yale nkinga engenzeka, abasebenzi be-MRI baqaphela ngokucophelela ekuqinisekiseni ukuphepha kweziguli.
I-Noise
Iziguli zivame ukukhononda ngomsindo 'wokumangalisa' obangelwa yimishini ye-MRI. Lo msindo uvela kumaginethi we-gradient echazwe ngaphambilini. Lezi magnets ezinama-gradient empeleni zincane kakhulu uma ziqhathaniswa nombuthe we-MRI oyinhloko, kodwa zibalulekile ekuvumela ukuguqulwa okucashile ensimini yamagnetic ukuze 'ubone' ingxenye efanele yomzimba.
Isikhala
Ezinye iziguli ziyi-claustrophobic futhi ayithandi ukungena kumshini we- MRI . Ngenhlanhla, kunezinketho eziningi ezitholakalayo.
- I-MRIs eyingozi
Ama-MRIs amasha akudingi ukuba ulale ngaphakathi kwipayipi. Esikhundleni salokho, iziguli ezine-MRI emadolweni, ezinyaweni, ezinyaweni, emgqeni, noma esihlalweni, zingamane zibeke leyo ngxenye yomzimba ngaphakathi komshini we-MRI. Lolu hlobo lomshini alisebenzeli i-MRI yamahlombe, umgogodla, iziqhwa, noma i-pelvis. - Vula i-MRIs
I-MRIs evulekile yayinezinkinga ezibalulekile zekhwalithi, kodwa ubuchwepheshe bezithombe buye bukhula kancane eminyakeni embalwa edlule. Ngenkathi i-MRIs evaliwe isayithandwa odokotela abaningi , i-MRI evulekile ingaba enye ehlukile. - Ukuzijabulisa
Ezinye iziguli zinenkathazo ukuhlala zihlala imizuzu engu-45 kuthatha ukuqeda i-MRI, ikakhulukazi ngomsindo othakazelisayo. Ngakho-ke, kungase kube kufanele ukuthatha imithi yokuphumula ngaphambi kokufunda isifundo se-MRI. Xoxa ngalokhu nodokotela wakho ngaphambi kokuhlela isifundo se-MRI.