RESPON PHOTOSTIMULABLE PHOSPHOR (PSP) PADA COMPUTED RADIOGRAPHY TERHADAP AKURASI TEGANGAN TABUNG DAN LINIERITAS KELUARAN PESAWAT SINAR-X

*Dwi Adhianto  -  Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang, Indonesia
Heri Sutanto  -  Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang, Indonesia
Zaenal Arifin  -  Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang, Indonesia
Published: 1 Jul 2014.
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Abstract

The research has been done to analyze Photostimulable Phosphor (PSP) in Computed Radiography (CR) responses related to exposure factor variation which usually used in determining of tube voltage accuracy and output linearity of X-ray machine. The aim of this research is to analyze of linear response of PSP to variation of exposure factor that related to usage of tube voltage in kVp and tube current-exposure time (mAs).

The Method which used was exposing CR with an ascent of tube voltage 50 till 90 kVp with a constant tube current-exposure time in 0,5 till 16 mAs. Exposure Index, Deviation Index, and Indicated Equivalent Air Kerma (KIND) referred to  IEC standard 62494-1 at each expose and mean gray value of digital image were used as PSP responses. Those are related to kVp and mAs variation. The result was obtained that photostimulable phosphor response in Exposure Index and Deviation Index parameters had correlation coefficient >0.97 in logarithmic relation at all exposure factor variation. Parameter of Indicated Equivalent Air Kerma (KIND) referred to IEC standard 62494-1 had linier relation with >0.97 amount of correlation coefficient. Linearity coefficient was obtained 0.005-0.061 using IEC standard/mAs. Mean gray value had correlation coefficient >0.94 in logarithmic relation at using of steady tube voltage with the result that could be indicator of output linearity of X-ray machine. The result was obtained that mean gray value could be a tube voltage accuracy indicator at using of 0.5 till 8 mAs with correlation coefficient >0.83 amount.

Keywords : computed radiography, exposure indicator, mean gray value, output linearity, tube voltage accuracy

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