Effects of Voltage and Current Values to Patient Dose by CTDI Phantom

Abstract

Computed tomography is a modern device and plays an important role in diagnostic imaging. The aim of this study was to examine the dose changes in two water-equivalent cylindrical phantoms with different diameters, one 16 cm in diameter and the other 32 cm in diameter, by changing the tube voltage (kVp), tube current (mU) and slices thickness values in CT. The absorbed dose values obtained by the ionization chamber were converted to the relevant parameters by means of a package program available on the computer. The calculated CTDI_vol for a given volume and the DLP values giving the total dose value taken during the cross-sectional length were compared. As can be seen from the results of the study, the dose increases with increasing the current and voltage values. Especially in small and thin patients such as the head phantom, the dose increase is higher.

Keywords

• CT,CTDI,Dose,Phantom

Voltaj ve Akım Değerlerinin Hasta Dozu Üzerindeki Etkilerinin CTDI Fantomu ile Araştırılması

Abstract

Bilgisayarlı tomografi (CT) günümüzde etkin bir şekilde kullanılan modern bir cihaz olup, tanısal görüntülemede çok önemli bir yer tutmaktadır. Bu çalışmanın amacı, CT’de tüp voltajı (kVp), tüp akımı (mAs) ve kesit kalınlığı değerlerini değiştirerek farklı çaplara sahip biri 16 cm çapında ve diğeri 32 cm çapında olan su eşdeğeri silindirik iki adet fantomda doz değişimlerini incelemektir. İyonizasyon odası ile okunan soğurulan doz değerleri bilgisayarda var olan bir paket programı yardımıyla ilgili parametrelere çevrilmiştir. Belli bir hacim için hesaplanan CTDI_vol ve kesit alınan uzunluk boyunca aldığı toplam doz değerini veren DLP değerleri karşılaştırılmıştır. Çalışma sonuçlarından da görüldüğü gibi, doz artışı akım ve voltaj değerini arttırdıkça yükselmektedir. Özellikle kafa fantomu örneğindeki gibi küçük ve zayıf hastalarda doz artışı daha fazladır.

Keywords

• CT,CTDI,Doz,Fantom

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