{"id":15,"date":"2022-12-16T18:18:07","date_gmt":"2022-12-16T18:18:07","guid":{"rendered":"http:\/\/microct.com.tr\/?page_id=15"},"modified":"2023-02-17T12:27:20","modified_gmt":"2023-02-17T12:27:20","slug":"xrm-microct","status":"publish","type":"page","link":"https:\/\/microct.com.tr\/?page_id=15","title":{"rendered":"XRM – microCT nedir"},"content":{"rendered":"Tomografi, MicroCT \u00c7ekim Teori ve Uygulama Bilgisayarl\u0131 Tomografi, bir x-\u0131\u015f\u0131n\u0131 radyasyon kayna\u011f\u0131ndan elde edilen x-\u0131\u015f\u0131n\u0131n dairesel hareket yaparken g\u00f6r\u00fcnt\u00fc kameras\u0131 ile olu\u015fturulan r\u00f6ntgen g\u00f6r\u00fcnt\u00fclerinin birle\u015ftirilerek silindirik bir hacimde 3 boyutlu g\u00f6r\u00fcnt\u00fc elde etme tekni\u011fidir. X-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131 ve kamera kar\u015f\u0131l\u0131kl\u0131 hareketi ile istenilen a\u00e7\u0131sal aral\u0131klarla 180 derecede veya 360 derecede elde edilen radyografik g\u00f6r\u00fcnt\u00fcler birle\u015ftirilir. G\u00f6r\u00fcnt\u00fcler X-Y boyutunda elde edilir ve Z-Boyutunda dijital kesitler olu\u015fturulur. MicroCT cihaz\u0131 ise, benzer bir g\u00f6r\u00fcnt\u00fcleme tekni\u011fi ile \u00e7al\u0131\u015fmakta, fakat teknik olarak farkl\u0131l\u0131klar bulundurmaktad\u0131r. Medikal Tomografilerden CBCT tekni\u011fi ile g\u00f6r\u00fcnt\u00fc elde eden cihazlar benzer teknikte \u00e7al\u0131\u015fmakla beraber farkl\u0131l\u0131klar\u0131 mevcuttur. CBCT cihazlar\u0131 merkezdeki obje \u00fczerinde tam dairesel hareket ile g\u00f6r\u00fcnt\u00fc olu\u015fturmakta, x-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131 ve g\u00f6r\u00fcnt\u00fc kameras\u0131 sabit konumda kalmaktad\u0131r. MicroCT\u2019de ise x-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131 ve kamera hareket edilerek farkl\u0131 \u00e7\u00f6z\u00fcn\u00fcrl\u00fcklere ula\u015f\u0131lmaktad\u0131r. MicroCT cihazlarda x-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131 odak nokta boyutu 5-8 mikrometre boyutundad\u0131r. Bu de\u011fer \u00e7\u00f6z\u00fcn\u00fcrl\u00fc\u011f\u00fc etkileyen en \u00f6nemli etkenlerden biridir. G\u00f6r\u00fcnt\u00fc kamera piksel boyutu ve numune boyutu di\u011fer etkenlerdendir.\r\n\r\n \r\n\r\n\"\"\r\n\r\n \r\n\r\nMicroCT i\u00e7in kullan\u0131lan x-\u0131\u015f\u0131n\u0131 kaynaklar\u0131n\u0131n mikro odak boyutlu x-\u0131\u015f\u0131n\u0131 kaynaklar\u0131 oldu\u011funu daha \u00f6nce belirtmi\u015ftik. Yukar\u0131da bulunan g\u00f6rselde bir microfocus (mikron seviyede x-\u0131\u015f\u0131n\u0131 kayna\u011f\u0131 odak nokta boyutu) \u00f6rne\u011fi g\u00f6sterilmektedir. Bu sebeple elde edilen x-\u0131\u015f\u0131n\u0131 \u0131\u015f\u0131n miktar\u0131 medikal tomografi cihazlar\u0131 ile kar\u015f\u0131la\u015ft\u0131r\u0131lmamal\u0131d\u0131r. MicroCT cihazlarda kullan\u0131lan x-\u0131\u015f\u0131n\u0131 t\u00fcpleri \u00e7ok d\u00fc\u015f\u00fck say\u0131da x-\u0131\u015f\u0131n\u0131 \u0131\u015f\u0131n\u0131 \u00fcretmektedir, foton say\u0131s\u0131 d\u00fc\u015f\u00fckt\u00fcr. X-\u0131\u015f\u0131n\u0131 madde ile etkile\u015fime girdi\u011finde bir k\u0131sm\u0131 so\u011furulur ve bir k\u0131sm\u0131 ise enerji seviyesi azalarak maddeyi deler ge\u00e7er. Maddeyi ge\u00e7en bu \u0131\u015f\u0131nlar enerji seviyesine ve b\u00fcy\u00fckl\u00fc\u011f\u00fcne g\u00f6re g\u00f6r\u00fcnt\u00fc kameras\u0131 \u00fczerinde bir elektrik sinyali olu\u015fturur. Her sinyal, b\u00fcy\u00fckl\u00fc\u011f\u00fcne g\u00f6re bir de\u011fer ifade eder ve bu de\u011ferler gurubu, 0-255 siyah beyaz renk tonlar\u0131 aral\u0131\u011f\u0131nda bir radyografik g\u00f6r\u00fcnt\u00fc olu\u015fturur. Maddenin x-\u0131\u015f\u0131n\u0131 ile etkile\u015fimi farkl\u0131 seviyelerde ger\u00e7ekle\u015fmektedir. Atom \u00e7ekirde\u011fi ile elektron bulutu aras\u0131 bo\u015fluk y\u00fcksek seviyede oldu\u011fu i\u00e7in, x-\u0131\u015f\u0131n\u0131n y\u00fcksek \u00e7o\u011funlu\u011fu absorption, yani so\u011furulma \u015feklinde etkile\u015fimde bulunur. K\u00fctle numaras\u0131 k\u00fc\u00e7\u00fck olan atomlarda x-\u0131\u015f\u0131n\u0131 etkile\u015fimi az oldu\u011fu i\u00e7in daha kolay bir g\u00f6r\u00fcnt\u00fc elde edilebilirken, k\u00fctle numaras\u0131 y\u00fcksek olan atomlarda so\u011furulma miktar\u0131 y\u00fcksektir. Yani k\u00fctle numaras\u0131 veya Atom numaras\u0131 artt\u0131k\u00e7a so\u011furulma artar ve g\u00f6r\u00fcnt\u00fc sa\u011flayacak x-\u0131\u015f\u0131n\u0131 miktar\u0131 ve enerji seviyesi azal\u0131r. G\u00f6r\u00fcnt\u00fcleme zorla\u015f\u0131r. MicroCT taramas\u0131 yap\u0131lacak numunelerde dikkat edilmesi gereken hususlar, taranacak malzemenin atom i\u00e7eri\u011fi, malzeme yo\u011funlu\u011fu, boyutu ve \u015fekli olmal\u0131d\u0131r.\r\n\r\n\"\"\r\n
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