I-MRI Homogeneity

Ukufana kwenkundla kazibuthe (homogeneity), okwaziwa nangokuthi ukufana kwenkundla kazibuthe, kubhekisela ekukhombeni kwenkundla kazibuthe ngaphakathi komkhawulo othize wevolumu, okungukuthi, noma ngabe imigqa yakazibuthe endaweni yonkana iyafana. Ivolumu ethile lapha ngokuvamile iyisikhala esiyindilinga. Iyunithi yokufana kwendawo kazibuthe i-ppm (ingxenye ngesigidi), okungukuthi, umehluko phakathi kwamandla enkambu aphezulu kanye namandla enkundla kazibuthe aphansi endaweni ethile ehlukaniswe amandla enkambu ayisilinganiso aphindwe ngesigidi esisodwa.

I-MRI idinga izinga eliphezulu lokufana kwenkundla kazibuthe, enquma ukulungiswa kwendawo kanye nesilinganiso sesignali-kumsindo wesithombe ebangeni lesithombe. Ukufana okungekuhle kozibuthe kuzokwenza isithombe sifiphale futhi sihlanekezelwe. Ukufana kwensimu kazibuthe kunqunywa ukwakheka kukazibuthe uqobo kanye nemvelo yangaphandle. Lapho inkulu indawo yesithombe sikazibuthe, ukufana kwensimu kazibuthe ephansi kungafinyelelwa. Ukuzinza kwendawo kazibuthe kuyinkomba yokukala izinga lokukhukhuleka lamandla kazibuthe ngokuhamba kwesikhathi. Phakathi nenkathi yokulandelana kwesithombe, ukukhukhuleka kwamandla kazibuthe kuzothinta isigaba sesignali ye-echo elinganiswe ngokuphindaphindiwe, okuholela ekuhlanekeni kwesithombe nokuncipha kwesilinganiso sesignali-kuya-nomsindo. Ukuzinza kwendawo kazibuthe kuhlobene eduze nohlobo lukazibuthe kanye nekhwalithi yomklamo.

Ukunikezwa kwezinga lokufana kwendawo kazibuthe kuhlobene nosayizi nokuma kwesikhala sokulinganisa esithathiwe, futhi ngokuvamile zisebenzisa isikhala esiyindilinga esinobubanzi obuthile kanye nendawo emaphakathi uzibuthe njengobubanzi bokulinganisa. Imvamisa, ukumelwa kokufana kwenkundla kazibuthe kusesimweni sesikhala esithile sokulinganisa, ububanzi bokushintshwa kwamandla kazibuthe endaweni esinikeziwe (inani le-ppm), okungukuthi, ingxenye eyisigidi yamandla kazibuthe ayinhloko (ppm) njengeyunithi yokuchezuka ukuze kuvezwe ngokomthamo, ngokuvamile le yunithi yokuchezuka ibizwa ngokuthi ppm, okubizwa ngokuthi ukumelela inani eliphelele. Isibonelo, ukufana kwenkundla kazibuthe phakathi kwawo wonke isilinda sokuvula isheke sokuskena kungu-5ppm; Ukufana kwenkundla kazibuthe esikhaleni esiyindilinga esingu-40cm kanye no-50cm okugxile esizindeni sikazibuthe ngu-1ppm no-2ppm, ngokulandelana. Kungase futhi kuvezwe ngokuthi: ukufana kwenkundla kazibuthe esikhaleni sekhiyubhu yesentimitha eyi-cubic ngayinye endaweni yesifanekiso esivivinywayo ngu-0.01ppm. Kungakhathalekile izinga, ngaphansi kwesisekelo sokuthi usayizi we-sphere wokulinganisa uyafana, inani elincane le-ppm libonisa ukuthi kungcono ukufana kwenkundla kazibuthe.

Esimeni sedivayisi ye-1.5-tMRI, ukushintshashintsha kokukhukhuleka kwamandla kazibuthe amelelwa iyunithi eyodwa yokuchezuka (1ppm) ngu-1.5×10-6T. Ngamanye amazwi, ohlelweni lwe-1.5T, ukufana kwenkundla kazibuthe okungu-1ppm kusho ukuthi inkambu kazibuthe eyinhloko inokuguquguquka kokukhukhuleka okungu-1.5×10-6T (0.0015mT) okusekelwe ngemuva kwamandla kazibuthe angu-1.5T. Ngokusobala, emishinini ye-MRI enamandla ahlukene enkambu, ukuhlukahluka kwamandla kazibuthe amelelwa yiyunithi ngayinye yokuphambuka noma i-ppm ihlukile, kusukela kulo mbono, izinhlelo zensimu ephansi zingaba nezidingo eziphansi zokufana kwamagnetic field (bheka Ithebula 3-1) . Ngolungiselelo olunjalo, abantu bangasebenzisa izinga lokufana ukuze baqhathanise kalula amasistimu anamandla enkundla ahlukene, noma amasistimu ahlukene anamandla afanayo enkundla, ukuze bahlole ngokunembile ukusebenza kukazibuthe.

Ngaphambi kwesilinganiso sangempela sokufana kwenkundla kazibuthe, kuyadingeka ukucacisa ngokunembile isikhungo sikazibuthe, bese uhlela ithuluzi lokulinganisa amandla ensimu (imitha ye-Gauss) kumkhakha wesikhala werediyasi ethile, futhi ulinganise amandla ayo kazibuthe. iphuzu nephuzu (indlela yendiza engu-24, indlela yendiza eyi-12), futhi ekugcineni icubungule idatha ukuze kubalwe ukufana kwenkundla kazibuthe phakathi kwawo wonke umthamo.

Ukufana kwendawo kazibuthe kuzoshintsha nendawo ezungezile. Ngisho noma uzibuthe ufinyelele izinga elithile (inani eliqinisekisiwe lemboni) ngaphambi kokushiya ifektri, Nokho, ngemva kokufakwa, ngenxa yethonya lezici zemvelo ezifana nokuzivikela kazibuthe (self-) shielding, RF shielding (iminyango neWindows), ipuleti le-waveguide. (ithubhu), isakhiwo sensimbi phakathi kozibuthe nezisekelo, izinto zokuhlobisa umhlobiso, izinto zokukhanyisa, amapayipi okungenisa umoya, amapayipi omlilo, iziphephetha-moya zezimo eziphuthumayo, izinto eziphathwayo (ngisho nezimoto, amakheshi) eduze kwezakhiwo ezisezingeni eliphezulu naphansi, ukufana kwazo kuzoshintsha. Ngakho-ke, ukuthi ukufana kuyahlangabezana yini nezidingo zokuthwebula kwe-magnetic resonance kufanele kusekelwe emiphumeleni yangempela yokulinganisa ngesikhathi sokwamukelwa kokugcina. Ileveli yenkundla yokwenziwa kanye nokuleveliswa kwenkundla esebenzayo yekhoyili ye-superconducting eyenziwe unjiniyela wokufaka womkhiqizi we-magnetic resonance efektri noma esibhedlela yizinyathelo ezibalulekile zokuthuthukisa ukufana kwendawo kazibuthe.

Ukuze kutholwe indawo amasiginali aqoqiwe kunqubo yokuskena, okokusebenza kwe-MRI kudinga futhi ukweqa inkambu kazibuthe yegradient △B ngezinguquko eziqhubekayo nezikhulayo ngesisekelo senkambu kazibuthe eyinhloko engu-B0. Kuyacatshangwa ukuthi inkambu yegradient △B ebekwe ngaphezu kwevoxel eyodwa kufanele ibe nkulu kunokuchezuka kwendawo kazibuthe noma ukushintshashintsha kokukhukhuleka okubangelwa indawo kazibuthe eyinhloko engu-B0, ngaphandle kwalokho izoshintsha noma iqede isignali yendawo engenhla, okuholela kuma-artifacts kanye ukunciphisa ikhwalithi yesithombe.

Ukuchezuka okukhulu kanye nokugudluka kokukhukhuleka kwendawo kazibuthe ekhiqizwa inkambu kazibuthe eyinhloko engu-B0, kuba kubi kakhulu ukufana kwendawo kazibuthe, yehlisa ikhwalithi yesithombe, futhi kuhlobene ngokuqondile nokulandelana kokucindezela kwe-lipid (umehluko wefrikhwensi ye-resonance phakathi amanzi namafutha emzimbeni womuntu angama-200Hz kuphela) kanye nempumelelo yokuhlolwa kwe-magnetic resonance spectroscopy (MRS). Ngakho-ke, ukufana kwamagnetic field kungenye yezinkomba ezibalulekile zokulinganisa ukusebenza kwemishini ye-MRI.

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Isijovo semidiya esinokucindezela okuphezulus futhi ziyizisetshenziswa ezisizayo ezibaluleke kakhulu emkhakheni wezithombe zezokwelapha futhi zivame ukusetshenziselwa ukusiza abasebenzi bezokwelapha ukuletha imidiya ehlukile ezigulini. I-LnkMed ingumkhiqizi ose-Shenzhen osebenza ngokukhethekile ekukhiqizeni le mishini yezokwelapha. Kusukela ngo-2018, ithimba lezobuchwepheshe benkampani beligxile ocwaningweni nasekukhiqizweni kwama-ejenti wokuqhathanisa nengcindezi ephezulu. Umholi weqembu ungudokotela onolwazi olungaphezu kweminyaka eyishumi lwe-R&D. Lezi zinguquko ezinhleI-CT injector eyodwa,I-CT double head injector,Umjovo we-MRIfuthiI-Angiography ephezulu yomfutho wegazi injector(I-DSA injector) ekhiqizwe i-LnkMed futhi iqinisekisa ubungcweti bethimba lethu lezobuchwepheshe - idizayini ebambene futhi elula, izinto eziqinile, i-Factory Perfect, njll., ziye zathengiswa ezibhedlela ezinkulu zasekhaya nezimakethe zangaphandle.