Magnet na Dindindin don MRI & NMR

Magnet na Dindindin don MRI & NMR

Babban abu mai mahimmanci na MRI & NMR shine magnet.Ƙungiyar da ke gano wannan ma'aunin maganadisu ana kiranta Tesla.Wani ma'auni na gama gari da ake amfani da shi akan maganadisu shine Gauss (1 Tesla = 10000 Gauss).A halin yanzu, maganadisun da ake amfani da su don yin hoton maganadisu na maganadisu suna cikin kewayon 0.5 Tesla zuwa 2.0 Tesla, wato, 5000 zuwa 20000 Gauss.


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Menene MRI?

MRI fasaha ce ta hoto mara cin zarafi wacce ke samar da cikakkun hotuna masu girma uku girma.Ana amfani da shi sau da yawa don gano cututtuka, ganewar asali, da kuma kula da magani.Ya dogara ne akan ingantacciyar fasaha wanda ke zugawa da gano canjin yanayin jujjuyawar protons da aka samu a cikin ruwa wanda ke samar da kyallen takarda masu rai.

MRI

Ta yaya MRI ke aiki?

MRIs suna amfani da maganadisu masu ƙarfi waɗanda ke samar da filin maganadisu mai ƙarfi wanda ke tilasta protons a cikin jiki don daidaitawa da wannan filin.Lokacin da aka kunna mitar rediyo ta wurin majiyyaci, protons suna motsa jiki, kuma suna jujjuya daga ma'auni, suna tauyewa da jan filin maganadisu.Lokacin da aka kashe filin mitar rediyo, na'urori masu auna firikwensin MRI suna iya gano makamashin da aka fitar yayin da protons suka daidaita da filin maganadisu.Lokacin da protons ke ɗauka don daidaitawa da filin maganadisu, da kuma adadin kuzarin da aka saki, yana canzawa dangane da yanayi da yanayin sinadarai na ƙwayoyin.Likitoci suna iya bambanta tsakanin nau'ikan kyallen takarda daban-daban dangane da waɗannan kaddarorin maganadisu.

Don samun hoton MRI, an sanya majiyyaci a cikin babban maganadisu kuma dole ne ya kasance har yanzu yayin aiwatar da hoto don kada ya ɓata hoton.Ana iya ba da ma'auni masu bambance-bambance (sau da yawa suna ɗauke da kashi Gadolinium) ga majiyyaci a cikin jini kafin ko lokacin MRI don ƙara saurin da protons ke daidaitawa da filin maganadisu.Da sauri protons suna daidaitawa, hoton yana haskakawa.

Wadanne nau'ikan maganadiso ne MRI ke amfani da su?

Tsarin MRI yana amfani da nau'ikan nau'ikan maganadisu guda uku:

-Ana yin maganadisu masu juriya daga nau'ikan wayoyi da yawa da aka naɗe da su a cikin silinda wanda ake bi ta wutar lantarki.Wannan yana haifar da filin maganadisu.Lokacin da aka kashe wutar lantarki, filin maganadisu ya mutu.Waɗannan maɗaukaki suna da ƙasa da tsada don yin fiye da magnet mai ɗaukar nauyi (duba ƙasa), amma suna buƙatar adadin wutar lantarki mai yawa don aiki saboda juriyar dabi'ar waya.Wutar lantarki na iya yin tsada lokacin da ake buƙatar magneto mai ƙarfi.

-Magnet na dindindin shine kawai -- dindindin.Filin maganadisu koyaushe yana nan kuma koyaushe yana cikakken ƙarfi.Saboda haka, ba kome ba don kula da filin.Babban koma baya shi ne cewa waɗannan maganadiso suna da nauyi sosai: wani lokacin da yawa, ton da yawa.Wasu filaye masu ƙarfi za su buƙaci maganadisu don haka nauyi zai yi wuya a gina su.

-Superconducting maganadiso ne da nisa da aka fi amfani a MRIs.Superconducting maganadiso suna da ɗan kama da resistive maganadiso - coils na waya tare da wucewa lantarki halin yanzu haifar da Magnetic filin.Bambanci mai mahimmanci shine cewa a cikin maɗaukakin maganadisu mai ƙarfi da waya tana ci gaba da yin wanka da helium na ruwa (a yanayin sanyi 452.4 digiri ƙasa da sifili).Wannan kusan sanyin da ba za a iya misaltawa ba yana sauke juriyar waya zuwa sifili, tare da rage buƙatun wutar lantarki ga tsarin kuma ya sa ya fi ƙarfin aiki.

Nau'in maganadisu

Zane na MRI da gaske an ƙaddara ta nau'i da tsari na babban maganadisu, watau rufe, MRI irin rami ko MRI budewa.

Abubuwan maganadiso da aka fi amfani da su sune na'urorin lantarki masu ƙarfi.Waɗannan sun ƙunshi naɗaɗɗen wuta wanda aka yi shi da ƙarfi ta hanyar sanyaya ruwa mai helium.Suna samar da filayen maganadisu masu ƙarfi, masu kama da juna, amma suna da tsada kuma suna buƙatar kiyayewa akai-akai (wato sama da tankin helium).

A yayin da aka yi hasarar superconductivity, ƙarfin lantarki yana ɓacewa azaman zafi.Wannan dumama yana haifar da saurin tafasawar ruwan Helium wanda ke rikidewa zuwa babban ƙarar Helium mai iskar gas (quench).Don hana konewar thermal da asphyxia, maɗaukaki masu ƙarfi suna da tsarin tsaro: bututun fitarwa na iskar gas, saka idanu akan adadin oxygen da zafin jiki a cikin dakin MRI, buɗe kofa a waje (matsi a cikin ɗakin).

Superconducting maganadiso yana ci gaba da aiki.Don iyakance ƙaƙƙarfan shigarwa na magnet, na'urar tana da tsarin garkuwa wanda ko dai m (ƙarfe) ko aiki (wani na'ura mai ƙarfi na waje wanda filinsa ya sabawa na na'urar da ke ciki) don rage ƙarfin filin da ya ɓace.

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Ƙananan filin MRI kuma yana amfani da:

- Resistive electromagnets, waɗanda suke da rahusa da sauƙin kulawa fiye da maɗaukakiyar maganadisu.Waɗannan ba su da ƙarfi sosai, suna amfani da ƙarin kuzari kuma suna buƙatar tsarin sanyaya.

-Maɗaukaki na dindindin, na tsari daban-daban, wanda ya ƙunshi abubuwan ƙarfe na ƙarfe na ferromagnetic.Ko da yake suna da fa'idar kasancewa marasa tsada da sauƙin kulawa, suna da nauyi sosai kuma suna da rauni cikin ƙarfi.

Don samun filin maganadisu mafi kamanni, maganadisu dole ne a daidaita shi da kyau (“shimming”), ko dai a hankali, ta yin amfani da guntuwar ƙarfe mai motsi, ko kuma a rayayye, ta amfani da ƙananan coils na lantarki da aka rarraba a cikin maganadisu.

Halayen babban maganadisu

Babban halayen magnet sune:

-Nau'i (superconducting ko resistive electromagnets, m maganadiso)
- Ƙarfin filin da aka samar, wanda aka auna a Tesla (T).A cikin aikin asibiti na yanzu, wannan ya bambanta daga 0.2 zuwa 3.0 T. A cikin bincike, ana amfani da magnets tare da ƙarfin 7 T ko ma 11 T da fiye.
-Homogeneity


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