Analisis Noise Level Hasil Citra Ct Scan pada Tegangan Tabung 120 Kv dan 135 Kv dengan Variasi Ketebalan Irisan (Slice Thickness)

Some of the parameters that influence noise level are tube voltage and slice thickness, that can affect image quality and accuracy in diagnosis, with a tolerance limit of the CT number ± 7 HU. The objective of this study is to define the noise level on the tube voltage 0f 120 kV and 135 kV with slice thickness variations. The measurement used water phantom scanning of head with tube voltage 120 kV, 135 kV and slice thickness 2, 3, 5, 7 and 10 mm. water phantom scanning of the abdomen with tube voltage 120 kV and slice thickness 3, 5, 7, 10 and 20 mm. Noise level got from central ROI area phantom. The high tube voltage and increasing the slice thickness, that the noise level decreases because the x-ray tube produced high x-rays energy and high photons penetrating to tissues. Noise levels are good when using eksposure parameters are current-time and tube voltage : 225 mAs, 135 kV with a slice thickness of 10 mm is 0.47 % for the head and 375 mAs, 120 kV with a slice thickness 3 mm is 0.45 % for the abdomen