Koj puas paub MRI?
Sib nqus resonance imaging (MRI), tseem hu ua spin imaging, siv lub hauv paus ntsiab lus ntawm nuclear magnetic resonance (NMR) los xyuas cov emission electromagnetic nthwv dej los ntawm kev siv lub gradient magnetic teb raws li qhov sib txawv attenuation ntawm lub zog tso tawm nyob rau hauv txawv structural ib puag ncig nyob rau hauv lub yam khoom. Txoj hauj lwm thiab hom ntawm lub nucleus ntawm cov khoom tuaj yeem paub, thiab cov qauv duab ntawm cov khoom tuaj yeem kos raws li qhov no.
Cov ntsiab lus tseem ceeb:
MRI yog biomagnetic nuclear spin imaging thev naus laus zis uas tau tsim kho sai nrog kev tsim cov tshuab hluav taws xob, hluav taws xob, circuits, superconductors thiab lwm yam thev naus laus zis. Cov kws kho mob suav nrog tus neeg mob' kev ntshai ntawm" nuclear", yog li cov txheej txheem no feem ntau hu ua" magnetic resonance imaging."
Lub" nucleus" ntawm MRI hais txog hydrogen nuclei, vim hais tias txog 70% ntawm tib neeg lub cev yog tsim los ntawm dej, thiab MRI cia siab rau hydrogen atoms hauv dej.
Thaum ib yam khoom raug muab tso rau hauv ib qho chaw sib nqus, nws yog irradiated nrog tsim nyog electromagnetic nthwv dej los hloov cov kev taw qhia ntawm hydrogen atom' s rotational kev npaj kom nws resonate, thiab ces soj ntsuam cov electromagnetic nthwv dej nws tso tawm. Cov ntaub so ntswg sib txawv yuav tsim cov cim hluav taws xob sib txawv, uas yog ua tiav los ntawm lub computer. Koj tuaj yeem paub txoj haujlwm thiab hom ntawm nuclei uas tsim cov khoom no, thiab raws li qhov no, koj tuaj yeem kos duab peb sab ntawm sab hauv ntawm cov khoom.
Thaum lub sij hawm precession ntawm lub atomic nucleus, nws absorbs lub xov tooj cua zaus pulse nrog tib zaus raws li lub precession zaus ntawm lub atomic nucleus, uas yog, qhov zaus ntawm kev siv alternating magnetic teb yog sib npaug zos rau Larmor zaus, thiab lub atomic nucleus undergoes. resonance nqus. Tom qab lub xov tooj cua zaus pulse raug tshem tawm, lub sij hawm nuclear sib nqus txo lub zog absorbed Ib feem ntawm nws yog emissions nyob rau hauv daim ntawv ntawm electromagnetic tsis, uas yog hu ua resonance emission. Cov txheej txheem ntawm resonance absorption thiab resonance emission hu ua" nuclear magnetic resonance"
Disadvantages ntawm MRI:
Kev kuaj mob ntsws tsis zoo tshaj rau kev kuaj X-ray lossis CT, thiab daim siab, txiav, qog adrenal, thiab kev kuaj mob prostate tsis zoo dua rau CT, tab sis tus nqi ntau dua;
Nws tsis zoo li endoscopy rau kab mob plab;
Lub sij hawm scanning yog ntev thiab qhov kev daws teeb meem spatial tsis zoo tagnrho;
Vim muaj lub zog sib nqus, MRI tsis tuaj yeem siv rau cov neeg mob tshwj xeeb uas muaj hlau nplaum lossis cov pacemakers hauv lub cev.
