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. Ngokuvamile, ukumelwa kokufana kwenkundla kazibuthe kusesimweni esithile sokulinganisa isikhala, uhla loshintsho lokuqina kwenkundla kazibuthe endaweni esinikeziwe (inani le-ppm), okungukuthi, ingxenye eyisigidi yamandla kazibuthe ayinhloko (ppm) njengeyunithi yokuchezuka ukuze iveze ngokomthamo, ngokuvamile leyunithi yokuchezuka ibizwa ngokuthi i-ppm, ebizwa ngokuthi 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 ensimu, ukuhluka 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 kokulinganisa kwangempela kokufana kwenkundla kazibuthe, kuyadingeka ukunquma ngokunembile isikhungo sikazibuthe, bese uhlela ithuluzi lokulinganisa amandla ensimu (imitha ye-Gauss) uphenyo endaweni yesikhala yendawo engaba nguzibuthe, bese ukala iphuzu layo lamandla kazibuthe iphuzu ngephuzu (indlela yendiza engu-24, indlela yendiza engu-12), futhi ekugcineni ukucubungula idatha ukuze ubale yonke ivolumu yendima kazibuthe.

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-) isivikelo, i-RF shielding (iminyango ne-Windows), ipuleti le-waveguide (ishubhu), isakhiwo sensimbi phakathi komazibuthe nezisekelo, izinto zokuhlobisa, izinto zokukhanyisa, amapayipi okuphuza umoya, amapayipi okukhipha umlilo, imishini ephuthumayo yemoto, imishini ephuthumayo kuya ezakhiweni ezisezingeni eliphezulu naphansi, ukufana kwayo 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 ngaphezulu ku-voxel eyodwa kumelwe ibe nkulu kunokuchezuka kwenkundla kazibuthe noma ukushintshashintsha kokukhukhuleka okubangelwa indawo kazibuthe eyinhloko engu-B0, ngaphandle kwalokho izoshintsha noma iqede isignali yokuma yendawo engenhla, okuholela kuma-artifact kanye nokunciphisa ikhwalithi yokucabanga.

Uma kukhulu ukuchezuka nokuguquguquka 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 we-resonance frequency phakathi kwamanzi namafutha emzimbeni womuntu ungama-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,CT umjovo wekhanda kabili,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.