SPEKTRAL RENTGEN KOMPYUTER TOMOGRAFIYASIDA SPEKTRAL BUZILGAN CHIZIQLI YUTILISH KOEFFITSIYENTLARINI TO‘G‘IRLASH USULI
Keywords:
Koʻp energiyali rentgen KT, Foton hisoblagich detektorlar, Miqdoriy rentgen xarakteristikasi, Ma’lumotlarni qayta ishlash usullari.Abstract
Ko‘p energiyali rentgen kompyuter tomografiyasida (KT) qo‘llaniladigan foton sanagich detektorlar (FSD) yuqori energiya ajratish qobiliyatini ta’minlaydi, ammo spektral buzilishlarga duch keladi. Bu buzilishlar zaryad almashinuvi, impuls to‘planishi va to‘liqsiz zaryad yig‘ilishi kabi fizikaviy hodisalardan kelib chiqadi. Natijada rekonstruksiya qilingan chiziqli susaytirish koeffitsientlari (CHSK) noto‘g‘ri bo‘lib qoladi, ayniqsa past energiyalarda. Ushbu ishda biz spektral buzilgan CHSK larni proyeksiya domenida tuzatishning hisoblash jihatdan samarali usulini taklif etamiz. Usul kiruvchi rentgen spektrining yoki oqim taqsimotining oldindan ma’lum bo‘lishini talab qilmaydi. Taklif etilayotgan usul xom proyeksiya ma’lumotlariga kanal bo‘yicha chiziqli va chiziqli bo‘lmagan parametrlashtirishni qo‘llaydi, parametrlar ma’lum referens materiallardan kalibrlanadi. Optimal parametrlar har bir energiya kanali uchun rekonstruksiya qilingan va jadval CHSK lar orasidagi farqni minimallashtirish yo‘li bilan aniqlanadi. Olingan parametrlar o‘rtacha qiymatga keltirilib, noma’lum materiallarning proyeksiya ma’lumotlarini tuzatish uchun qo‘llaniladi. Tajribaviy tekshiruv FSD dan olingan turli sinov materiallari ustida o‘tkazildi. Natijalar usul ko‘p energiyali CHSK larni butun energiya diapazonida yuqori aniqlik bilan tiklashini, ayniqsa past energiyalarda mavjud eng zamonaviy usul muvaffaqiyatsiz bo‘lgan joyda kuchli natija berishini ko‘rsatdi. Dreier va boshqalarning proyeksiya domeni usuli bilan solishtirganda, taklif etilayotgan usul 30 keV dan past energiyalarda aniqroq CHSK bahosini beradi, ixcham ma’lumot hajmini saqlab qoladi va hisoblash yuklamasini oshirmaydi. Usul turli KT tizimlari, rentgen spektrlari va detektor konfiguratsiyalariga osongina moslashtiriladi hamda spektral KT tasvirlashda miqdoriy material xarakteristikasini yaxshilash uchun foydalidir.
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